Unhid Suits
Environmental Protection
Agtncy
Offic* of R«*««rch
•nd Development
EPA /600/R-93/126
June 1993
&EPA Global Climates-
Past, Present, and Future
Activities for Integrated Science Education
Edited by: Sandra Henderson, Steven R. Holman, and Lynn L. Mortenscn
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Global Climates Past, Present, and Future:
Activities for Integrated Science Education
(Grades 8-10)
Edited bv
Sandra Henderson
ManTech Environmental Technology. Inc.
U.S. Environmental Protection Agency - Environmental Research Laboratory
Corvallii. Oregon
Steven R. Holman
ManTech Environmental Technology. Inc.
U.S. Environmental Protection Agency - En\ironmenlal Research Laboratory
Corvallii. Oregon
Lynn L. Mortensen
Uni\-ersity of Nebraska
Lincoln, Nebraska
Scientist Partners and Authors
Hermann Gucinski Sandra Henderson Steven R. Holman
USDA Forest Sen-ice ManTech Environmental ManTech En\innmental
Technology. Inc. Technology, Inc.
George A. King DonaM L. Phillips
ManTech Environmental U.S. En\ironmental
Technology. Inc. Protection Agency
Teachers Partners and Authors
Robert Cutting Robin Hammer WendiHercher
Joseph Lane Middle School Lakeridge High School Porrish Middle School
Gary Larsen Unify Mcjunkin
Centennial High School Weaern View Middle School
Science Educator Curriculum Development
Norman G« Ledciman Lynn L. Morfenxn
Oregon State University Unnersiry of Nebraska
Grahic Desin and
Betsy J.Huber
ManTech Environmental Technology, Inc.
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DISCLAIMER
The development of this curriculum has been funded by the U. S. Environmental Protection
Agency. This document has been prepared at the EPA Environmental Research Laboratory in
Corvallis, Oregon, through contract #68-08-0006 to ManTech Environmental Technologies, Inc.
It has been subjected to the Agency's peer and administrative review and approved for
publication. Mention of trade names or commercial products does not constitute endorsement or
recommendation for use.
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Global Climates Past, Present, and Future:
Activities for Integrated Science Education
Table of Contents
Preface vii
Acknowledgements ix
How to Use This Book xi
Instructional Goals xiii
Climate Unit
1. Is the current weather "normal"? 1
2. What factors influence climate? 7
3. What is the relationship between climate and terrestrial biomes? 13
4. How has Earth and its climate changed over time? 19
5. What information do paleobotanists use to study ancient climates? 25
Greenhouse Effect Unit
6. What is a greenhouse and how does it trap heat from the sun? 39
7. What factors influence a greenhouse? 47
8. What makes Earth like a greenhouse? 53
Carbon Cycle Unit
9. What is the carbon cycle? 59
10. Where does CO2 come from? 65
Climate Change and the Greenhouse Gases Unit
11. How do scientists analyze greenhouse gases and global temperature overtime? 77
12. How does human activity contribute to greenhouse gas increases? 91
Possible Effects Unit
13. How might elevated CO2 affect plants? 97
14. What impact might sea level rise have? 103
15. How does science contribute to policy? 109
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Preface
It would be difficult to live in our information-rich
society and not be familiar with phrases such as
"global warming", "the greenhouse effect", and
"global climate change". But, how many people
actually understand what these terms mean? Many
people do not have an adequate scientific basis to
understand global climate change, its causes, or
possible effects. The pre-college school system can
play an important role in disseminating scientific
information on global climate change issues. To do so
will require a commitment from those professionals
in both the scientific and educational communities.
Although government agencies and educational
groups have recognized the need for closer
communication between research scientists and
educators, in practice, the linkage has never been
strong or well-defined.
Global Climates Past, Present, and Future:
Integrated Activities for Science Education is the
product of a partnership designed to help bridge the
gap between the scientific and educational
communities. This curriculum uses a current
environmental issue as the vehicle for teaching
science education. It is not the intent of the
curriculum to convince students that global
temperatures are rising at an unprecedented rate, but
rather to present the results of research and encourage
students to apply critical thinking skills to complex
issues such as global climate change.
The project began in January 1991, when five global
climate change scientists from the U.S.
Environmental Protection Agency's Environmental
Research Laboratory in Cbrvallis, Oregon met with
five middle and high school teachers, a university
science educator, and a university curriculum
development specialist to design the framework for a
curriculum addressing global climate change. The
scientists brought to the partnership their knowledge
and understanding of the complexity of climate
change issues as well as their ideas for student
activities and experiments. The teachers contributed
their expertise in science teaching, understanding
student needs, and "what really works in a
classroom".
The partnership was further encouraged at an
intensive, week long wriu'ng workshop in June 1991
where a draft curriculum was developed. Throughout
the summer, all involved in the project continued
editing and informal testing to ready the curriculum
for the actual classroom field test in the fall. During
the classroom testing phase, the teachers kept
detailed notes indicating the strengths and
weaknesses of the various activities and made
adjustments where appropriate. The scientists met
with the partner teachers and their classes throughout
the 1991-92 academic year and were available as
resources.
Based on teacher comments and experiences, a final
draft of the curriculum was completed during the
summer of 1992. The revised copy was sent to global
climate change scienusts and university science
educators for a final review.
The scientific foundation of the curriculum is based
on:
1. The fundamental components of the climate
system, including the hydrosphere, atmosphere,
and biosphere,
2. The scientific uncertainties involved in
predicting the rate and magnitude of climate
change.
3. The likely impacts of rapid climate change on
ecosystems.
The National Science Teachers' Association, in a
1982 position statement, stated that the goal of
science education was to "develop scientifically
literate individuals who understand bow science.
technology, and society influence one another and
who are able to use this knowledge in their everyday
decision-making." It is the intent of this curriculum
project to contribute to this goal.
VI
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Acknowledgements
The planning, testing, and production of this curriculum required the input and support of many individuals.
The editors gratefully acknowledge the talents of all persons whose contributions led to the completion of this
curriculum. Particular thanks are extended to the following:
Contributors and Technical Advisors
Dominique B&chelet
ManTech Environmental Technology. Inc.
Jerry R. Barker
ManTech Environmental Technology, Inc.
Carole Beedlow
Corvallis High School
Sue Black
Arogon High School
Robert Cutting
Joseph Lane Middle School
Robert K. Dixon
US. Environmental Protection Agency
Hermann Gucinski
USDA Forest Sen-ice
Robin Harrower
Lakeridge High School
Wendi Hercher
Parrish Middle School
John Kimball
Oregon Slate University
George A. King
ManTech Environmental Technology. Inc.
Gary Larsen
Centennial High School
Jeffrey J. Lee
US. Environmental Protection Agency
Linda Mcjunkin
Western View Middle School
Donald L. Phillips
US. Environmental Protection Agency
David P. Turner
ManTech Environmental Technology. Inc.
Science Education Reviewers
Rodger Bybee
Biological Sciences Cmmc*bon Study
Norman G. Lederrnan
Oregon State University
Cheryl Mason
San Diego State University
Document Production
BrendaT.Cul pepper
ManTech Environmental Technology. Inc. (RTF)
Chuck Gaul
ManTech Environmental Technology, Inc. (RTF)
Betsy J.Huber
ManTech Environmental Technology, Inc. (KTP)
Leigh Ann Larkin
ManTech Environmental Technology. Inc.
Irish Miller
ManTech Environmental Technology, inc.
PeteWinz
ManTech Environmental Technology. Inc. (KTP)
Additional Contributors
Roger Eckhardt
Los Alamos National Laboratory
John Engs
Oregon State University
JetTGunn
Cheldin Middle School
Dianne Hyer
Los Alamos National Laboratory
Paula Minear
CorvaUis High School
Paulette Murphy
National Oceanic and Atmospheric Administration
JoeNevius
Part Middle School
RonOkarma
Kennlwict Middle School
Hilary Staatz
Oregon State University
Tim Stewart
Sou* Albany High School
MarjWdser
Woodbun Middle School
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How to Use This Book
Curriculum Integration
Global Climates Past, Present, and Future: Activities
for Integrated Science Education was designed to be
integrated into existing science curriculum for grades
8-10. Each module is written with the developmental
needs of these students in mind, recognizing that
adaptations will be necessary depending on the
unique characteristics of each group of students in
each part of the country where this is used.
Unit Selection
This curriculum is intended to be flexible for the
teacher to select some or all of the activities at any
time of the year considered appropriate. Units build
on the content and learning of previous units yet are
not dependent on previous knowledge. Thus, units
and activities may be implemented sequentially or the
order may be altered to fit existing curriculum
organization of content.
Experiential Learning
Effon was made to incorporate hands-on experiential
learning in each activity'. Student outcomes include
data generation, recording and analysis, as well as
problem solving, speculating, and decision-making.
Students will be immersed in the process of scientific
inquiry while considering actual questions facing the
scientific community and general public today.
Authentic Assessment
Authentic assessment is incorporated through the use
of learning logs collected in notebooks or portfolios.
In the same way that scientists' notebooks serve as
critical records of their thoughts, plans, activities, and
conclusions, so should the learning logs serve as
records of the students' understanding, reasoning
skills, activities, and conclusions. Suggestions for
uses of the logbooks are provided below.
Student Logbooks
Students using this curriculum should keep a detailed
logbook of the entire unit. The logbook is analogous
to the notebooks scientists keep in virtually every
scientific discipline. In these, scientists record not
only the technical details of their experiments, they
also record their ideas, thoughts, plans, and failures.
Students should enter similar information in their
logs. Entries should include information and
observations on the day's activities, speculations,
reflections, and other information the student wishes
to express. The students should consider the notebook
to be an important scientific accoutrement to the
experiments and/or activities. To encourage
maximum creativity and freedom of expression, you
may wish to minimize the importance of grammar
and spelling, and allow students to choose a writing
style they are comfortable with. Collect the logbooks
periodically and carefully assess the entries. They
should accurately reflect the students' understanding
of the exercises, the outcomes, and how they relate to
the overall lesson goals.
Each activity is organized into sections:
Activity Subsections
• Thematic Question
• Lesson Focus
• Student Objectives
• Definition of Terms
• Estimated Time
• Activity Description
• Background Information
• Materials Needed
• Suggested Procedures
• Student Learning Portfolio
• Student Activity Guide
• Extensions
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Support Materials for Teachers
Some activities with extensive experiments have
student worksheets included. Graphic illustration and
transparency masters are provided for teachers and an
appendix with additional factual information as
background is also provided.
Additional Resources
The scientist/educator partnership used in designing
this curriculum proved to be a rewarding and
educational experience for all involved. Teachers are
encouraged to develop partnerships in their own
location utilizing expertise available in local
universities, cooperative extension, and research
facilities. A list of additional resources for
supplemental material and complementary
curriculum is included in the appendix.
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Instructional Goals
1. Familiarize students with scientific methods
allowing them to arrive at their own
explanations.
2. Help students understand the role of uncertainty
as it exists in the context of global change
research.
3. Encourage students to gather meaningful data in
the context of actual problems encountered in
global change research.
4. Engage students in hands-on, experiential
learning within the classroom and community.
5. Develop student learning artifacts (products that
demonstrate what students have learned) as
assessment tools.
6. Examine information regarding Earth's climate
as it currently exists, as it compares to other
planets, and as it influences life zones.
7. Analyze information regarding Earth's past
climate to gain insight into scientific processes
utilized in global climate change research.
8. Develop the concept of a greenhouse and how it
affects Earth.
9. Consider factors contributing to Earth's climatic
change and potential effects.
10. Evaluate controversial arguments regarding
global climate change issues.
XBJ
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Is the Current Weather "Normal"?
ACTIVITY 1
Lesson Focus:
Is the local daily weather different from the "normal" weather?
Objectives:
The student will be able to:
1 Distinguish between weather and climate.
2. Describe "normal" weather patterns.
3. Construct and interpret a graph of weather data.
Time:
1 or 2 days
Grade Level:
8-10
Key Concepts:
Current climate, data gathering, data analysis
Definitions of Terms:
Weather: Current atmospheric conditions
including temperature, rainfall, wind, and
humidity (e.g., what's going on outside now,
what's likely to happen tomorrow).
Climate: General weather conditions expected
in a given area, usually based on the 30-year
average weather. May also be applied more
generally to large-scale weather patterns in
time or space (e.g., an Ice Age climate, or a
tropical climate).
Background:
To separate daily weather from climate, the
National Weather Service uses values from the
past thiity years to compile "average** weather.
This 30-year average is generally considered
to represent the climate of the region being
CLIMATE UNIT
measured. In order to investigate the way that
the climate may be changing due to human
influences, scientists use the 30-year record.
They also use weather data from as far back as
the historical record will go, as long as the data
are accurate. Detailed daily weather data are
collected at surface meterological stations
(weather stations) located throughout the
world. One of the problems scientists face in
using historical data to understand climate
changes (particularly temperature changes) is
that many of weather stations are located in or
near urban areas. These areas often experience
warmer temperatures than surrounding rural
land due to the heat absorbing properties of
concrete and asphalt and the lack of shade and
evaporative cooling from vegetation. This
phenomenon is known as the "heat island
1
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ACTIVITY 1
effect". Scientists must also consider the fact
that the sites of many weather stations have
changed over time, often having been moved
from rural locations to airports. Long-term
weather records for these stations can be
difficult to interpret as they contain
measurements made at two different locations
across different periods of time.
Understanding and interpreting local weather
data and understanding the relationship
between weather and climate is a very
important first step to understanding larger-
scale global climate changes.
Activity:
Have students locate the weather section of a
local daily newspaper and graph both daily and
average or "normal" long-term data.
Newspaper weather sections often include
daily high and low temperatures, record high
and low temperatures, normal (or average)
high and low temperatures and current and
cumulative precipitation amounts (see attached
examples). By comparing current weather to
longer-term climate averages, the students will
gain an understanding of the important
differences.
Materials:
• Local weather information from newspaper
• Printed charts for the temperatures
• Colored pencils
Procedure:
1. Determine how long you want students to
collect weather data (a month, 3 months, all
year). One month of data collection is
usually sufficient to effectively illustrate
weather variation, but longer-term data
collection can serve to include seasonal
changes in the subsequent discussions.
2. Determine what weather data you are
interested in having students collect (e.g.,
daily high and low temperature, normal
high and low temperature, record high and
low temperature, daily precipitation,
normal precipitation, or record
precipitation).
3. Have the students prepare graphs to record
data (the detail of the graph will depend on
the duration of your weather data collection
and which data you choose to include). You
may wish to have the students post their
graphs around the room and add data to
them periodically.
4. Have students begin to collect data (don't
forget weekends) by clipping weather data
from a newspaper. Record this information
in a notebook.
5. Either daily or weekly, have students
record each day's weather data on the
graph. Also be sure to record the average or
"normal" values provided in the
newspaper. The comparison between the
average and daily weather data will form
the basis of the discussion of the
differences between weather and climate.
6. In a class discussion, ask the students to
compare daily weather data to the
"normal" or "average" data What features
do they observe? Lead the students to a
discussion of the differences between
weather and climate that they can observe
in their charts. Ask the students to consider
the following questions and discuss them
with the class:
CLIMATE UNIT
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ACTIVITY 1
a. For any of the weather data, which line
on the graph is more variable, the daily
values or average values? Why?
b. If you were asked to predict the weather
for tomorrow from the data shown on
the graph, what data would you find the
most useful, the daily or average
values? Why? How about if you had to
predict the weather for next week? Next
month?
c. If a scientist reported that last month in
Oregon was warmer than the same
month a year ago, would you consider
this to be evidence for climate change?
Why or why not? What kind of data do
you think would be the most
convincing, changes in short-term
(daily, weekly, monthly) weather, or in
longer-term climate data?
d. Based on the data the class has
collected, does this year appear to be
warmer, cooler, or about the same as the
average? From this data what, if
anything, can you conclude about
climate change?
Student Learning Portfolio:
1. Collected weather data, recorded in a
class notebook
2. Graphed weather data
3. Written answers to the questions above
Extensions:
1. For more detailed information on local
weather patterns, a Local Climatalogical
Data (LCD) Annual summary with
comparative data is available from the
National Oceanic and Atmospheric
Administration (NOAA) for a nominal
cosi. Check with your local U.S. Weather
Service Office or write to the National
Climatic Data Center, Asheville, North
Carolina, 28801 to determine the data
available for your area. The LCD summary
is comprised of temperature, precipitation,
and percentage daily sunshine data
including normals, means, and extremes
for the past 30 years. Using these detailed
data may be a more challenging and
informative route for students in higher
grades than the simple newspaper exercise
above. Students should be encouraged to
design their own charts for comparisons.
2. In addition to collecting and graphing local
data, consider doing this exercise in
cooperation with another school(s) in a
completely different geographic location.
Gasses could exchange their data with
each other for comparison and discussion.
This extension would be enhanced by
using telecommunication techniques to
establish computer links with other schools
to facilitate data exchange and student
communication.Q
CLIMATE UNIT
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ACTIVITY 1
Example —Temperature and precipitation readings from the Hometown Gazette newspaper.
Weather
February 9,1992
Temp. — High/Low
Sun. (through 4 p.m.) ...53/44
Normal 48/35
LasiYear 61/45
Record High 61 in 1991
Record Low -3 in 1950
Precipitation
Sun. (through 4 p.m.) ...Trace
To Date This Month 0.30
Normal to Date 0.33
To Date This Year 4.61
Normal to Date 6.49
Deficit to Date 1.88
Weather
February 10,1992
Temp. High/Low
Mon. (through 4 p.m.) ..59/35
Normal 48/35
Last Year 60/48
Record High 64 in 1963
Record Low 4 in 1950
Precipitation
Mon. (through 4 p.m.) ..Trace
To Date This Month 0.30
Normal to Date 0.49
To Date This Year 4.61
Normal to Date 6.59
Deficit to Date 1.98
Weather
February 11.1992
Temp. _~~~~~~~~ High/Low
Tues. (through 4 p.m.) ..59/42
Normal 48/35
Last Year 55/48
Record High 60 in 1963
Record Low 14 in 1989
Precipitation
Tues. (through 4 p.m.) ....0.00
To Date This Month 030
Normal to Dale 0.65
To Date This Year 4.61
Normal to Date 6.81
Deficit to Date 2.20
Weather
February 12,1992
Temp. High/Low
Wed. (through 4 p.m.) ..54/29
Normal 49/35
List Year 55/39
Record Hig! 58 in 1961
Record Low 9 in 1989
PreciptUtioo
Wed. (through 4 p.m.) ....0.00
To Date This Month 0.30
Normal to Date 0.80
To Date This Year 4.61
Normal to Date 6.%
Deficit to Date 2.35
Weather
February 13.1992
Temp. , High/Low
Thurs. (through 4 p.m.) 53/31
Normal 49/35
Last Year 58/33
Record High 58 in 1991
Record Low 15 in 1989
Precipitation
Thurs. (through 4 p.m.) ..0.00
To Date This Month 0.30
Normal to Date 0.95
To Date This Year 4.61
Normal to Date 7.11
Deficit to Date 2.50
Weather
February 14.1992
Temp. High/Low
Fri. (through 4 p.m.) 53/34
Normal 49/35
Last Year 58/37
Record High 60 in 1945
Record Low 21 in 1982
Precipitation
Fri. (through 4 p.m.) Trace
To Date This Month 0.30
Normal to Date 1.10
To Date This Year 4.61
Normal to Date 7.26
Deficit to Date 2.65
Weather
February 15.1992
Temp. High/Low
Sat. (through 4 p.m.).... 52/30
Normal 49/36
Last Year 57/35
Record High 60 in 1970
Record Low 25 in 1971
Precipitation
Sat (through 4 p.m.) 0.09
To Date This Month 0.39
Normal to Date 125
To Date This Year 4.70
Normal to Dale 7.41
Deficit to Date 2.71
Weather
February 16,1992
Temp. High/Low
Sun. (through 4 p.m.) ...55/42
Normal 5
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Is the Current Weather "Normal"?
STUDENTGUIDE—ACTIVITY 1
Definitions of Terms:
Weather: Current atmospheric conditions including temperature,
rainfall, wind, and humidity (e.g., what's going on outside now,
what's likely to happen tomorrow).
Climate: General weather conditions expected in a given area,
usually based on the 30-year average weather. May also be applied
more generally to large-scale weather patterns in time or space (e.g.,
an Ice Age climate, or a tropical climate).
Activity:
You will need to locate daily weather data
from a local newspaper and record your
findings in graph form. Daily weather data
often include high and low temperatures,
record high and low temperatures, and normal
high and low temperatures. Using weather
data collected from a local newspaper, graph
data and compare daily weather information
with longer term climate, trends. To separate
daily weather from climate the National
Weather Service uses values from the past
thirty years to compile "average" weather. In
the study of Global Climate Change, scientists
use even longer time periods, preferring to go
back as far as the historical record will go, as
long as it is accurate.
Materials:
• Local weather information from newspaper
• Printed charts for me temperatures
• Colored pencils
Procedure:
1. Prepare graphs to record data (the detail of
the graph will depend on the duration of
your weather data collection and which
data you choose to include).
2. Collect data (don't forget weekends) by
clipping weather data from a newspaper.
Record this information in a notebook.
3. Either daily or weekly, record each day's
weather data on die graph.
4. Using your graphs, compare daily weather
with normal and record weather and
answer the following questions in your
notebook and prepare to discuss the
answers in class.
a. For any of the weather data, which line
on the graph is more variable, the daily
values or average values?
Why?
b. If you were asked to predict the weather
for tomorrow from the data shown on
die graph, what data would you find die
most useful, die daily or average values?
CLIMATE UNIT
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SiuDENiGuiDE—ACTIVITY 1
Why?
How about if you had to predict the
weather for next week?
Next month?
If a scien'ist reported that last month in
Oregon *Vos warmer man the same
mon'Ji a year ago, would you consider
this to be evidence for climate change?
Why or why not?
What kind of data do you think would
be the most convincing, changes in
short-term (daily, weekly, monthly)
weather, or in longer-term climate date?
d Based on the data the class has
collected, does this year appear to be
warmer, cooler, or about the same as the
average?
From this data what, if anything, can
you conclude about climate changeTQ
Notes:
CLIMATE UNIT
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What Factors Influence Climate?
ACTIVITY 2
Lesson Focus:
How is climate influenced by both natural and human activities?
Objectives:
The student will be able to:
1. Make comparisons between different climates.
2. Identify factors that influence climate.
3. Discover climatic patterns through the use of precipitation,
temperature, and biome maps.
Time:
3 class periods
Grade Level:
8-10
Key Concepts:
Current climate, human influence on climate, map reading
Definitions of Terms:
Atmosphere: The gaseous envelope
surrounding Earth.
Geosphere: The solid portion of the Earth
comprising the crust, mantle, and core.
Hydrosphere: The portion of Earth where
water is present in either a liquid, gaseous, or
solid phase.
Biosphere: The portion of earth in which all
known life forms exist, consisting of a thin
envelope of air, water, and land
Background:
Many factors, both natural and anthropogenic
(human-made), determine Earth's climate. The
natural factors can include, but are not limited
to the following.
CLIMATE UNIT
1. Atmosphere: sun (energy, orbit, tilt, cycles),
reflection (albedo), clouds, precipitation,
wind, gases (H^O vapor, CO2, CH4),
feedbacks, and cycles.
2. Geosphere: geography (mountains, water
sources), volcanoes, surface roughness,
earth's core heat, feedbacks.
3. Hydrosphere: currents, surface roughness,
ice sheets, cycles, feedbacks.
4. Biosphere: living organisms, carbon
storage and cycling, evapotranspiration,
surface roughness, and feedbacks.
The human factors are often thought to have
influence on local climate, however, they may
also have regional and global effects. The
human factors include, but are not limited to
die following.
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ACTIVITY 2
1. Land Uses: slash and field burning,
deforestation, agriculture, wetlands, cities
("urban heat island" effect).
2. Resource Uses: burning of fossil fuels (oil,
wood, coal).
Activity:
Students will brainstorm and discuss ideas
about climate. Then they will create a class
mural depicting factors affecting climate
Materials:
• Maps and atlases (temperature,
precipitation, biomes for local, regional,
U.S., and world areas)
• Bulletin board or butcher paper
• Magazines
• Glue
• Scissors
• Colored markers
• Pads of sticky paper
Procedure:
Have the students cover a bulletin board with
poster paper or a long strip of butcher paper.
1. Introductory Discussion
(Ask the following questions):
a. What is the climate like in our area?
b. What do you think causes our climate
to be like this?
c. What is the climate like in a different
area such as the Amazon or the Arctic?
d What do you think causes thai climate
to be different?
2. Team Brainstorming
a. In small teams (3-5 students), have
students share their lists with each other
and compile a group list of factors
associated with climate.
b. Taking turns, have the teams each read
a factor aloud until all the lists are
exhausted The result will be a master
class list of factors the students perceive
to be associated with climate. Record
each factor on separate pieces of sticky
paper and stick the papers to the chalk
or bulletin board.
3. Categorize
a. Have students organize the sticky paper
factors into categories. (Suggested
categories: atmosphere, hydrosphere,
geosphere, and biosphere [natural
categories]; land use and resource use
[human categories]). Keep in mind that
the factors can overlap the arbitrary
categories, in which case, simply make
more sticky papers.
b. Ask students to divide the poster or
butcher paper into the above categories
(lengthwise) and label them. (See
Figure 1 for example.)
c. Let teams choose one of the
aforementioned categories (see 3a.) to
find photos (from magazines) to
represent the factors in this category
(two or more teams per category is
acceptable). Students should not be
restricted to magazines; original
drawings and photographs may be
contributed
4. Have the srudents build a mural as an
organizing framework.
CLIMATE UNIT
8
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ACTIVITY 2
Figure 1. Suggested Categories.
1
=1
Atmosphere
Hydrosphere
Geosphere
Biosphere
Land Use
Resource Use
Student Learning Portfolio: Extensions:
1. Draw mini-murals in logs It is improbable that students will think of all
2. Write stories to explain mural's content *c factors listed in the Background section. As
., ~ r r u~ . these factors are discovered and discussed in
3. Generate lists of new questions about . * „ . , . j.
.. the following lessons, photos and drawings
can be odtfo/ to the mural, using it as a basis
from which to build additional leaming.Q
CLIMATE UNIT
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ACTIVITY 2
Notes:
CLIMATE UNIT 10
-------
What Factors Influence Climate?
SiuDENiGuiDE—ACTIVITY 2
Definitions of Terms:
Atmosphere: The gaseous envelope surrounding Earth.
Geosphere: The solid portion of the Earth comprising the crust,
mantle, and core.
Hydrosphere: The portion of Earth where water is present in either a
liquid, gaseous, or solid phase.
Biosphere: The portion of earth in which all known life forms exist,
consisting of a thin envelope of air, water, and land.
Activity:
With other students in your class, you will
"brainstorm" and discuss ideas about weather
and climate. Incorporate these ideas into a
class mural depicting factors affecting climate
Materials:
• Maps aid atlases (temperature,
precipitation, and biomes for local, regional,
U.S., and world areas)
• Bulletin board or butcher paper
• Magazines
• Glue
• Scissors
• Colored markers
• Pads of sticky paper
Procedure:
1. Cover a bulletin board with poster paper or
a long strip of butcher paper.
2. Make a list of factors you associate with
climate.
3. Working in small teams, share your list
with others in your team. Make a team list
of factors you collectively associate with
climate.
4. Each team will take turns reading a factor
from their lists until all the lists are
exhausted Now you will have a class list
of factors you and your classmates
associate with climate. Record each factor
on separate pieces of sticky paper and stick
the papers to the chalk or bulletin board
5. Organize the sticky papers listing climate
factors into categories.
6. Divide the poster or butcher paper into the
categories you decided on and label them.
7. Each team will choose a category and find
photos or drawings to represent the factors
in your category.
8. Using the photos and drawings, build a
mural for your classroom.Q
CLIMATE UNIT
11
-------
STUDENTGUIDE—ACTIVITY 2
Notes:
C I I M A T E U N I T 12
A
-------
What Is the Relationship Between
Climates and Terrestrial Biomes?
ACTIVITY 3
Lesson Focus:
What are biomes and how do they interact with climate?
Objective:
The student will be able to:
1. Define the term "biome".
2. Locate and describe the characteristics of the major terrestrial
biomes of the world.
3. Compare a variety of biomes throughout the world
4. Describe the adaptive characteristics needed by plants and
animals in different biomes.
5. Summarize the relationship between climates and biomes.
Time:
2 days
Grade Level:
8-10
Key Concepts:
Currem climate, geographical regions, environmental adaptation
Definitions of Terms:
Biome: A geographic area characterized by
specific kinds of plants and animals.
Adaption: An inherited trait that increases an
organism's chance of survival in a particular
environment
Background:
Biomes refer to broad geographic regions mat
are characterized by relatively similar climate,
topography, flora, and fauna. These biomes are
generally identified by their dominant plant
life (e.g., grasslands, forests). Biomes seldom
have distinct boundaries. There are many
different classifications of the world's biomes
in varying degrees of detail. Generally they all
include the tundra, desert, forest, grasslands, or
some subset of these. Many biology textbooks
have maps of die world's biomes. Any of these
could be used for this activity.
CLIMATE UNIT
13
\
-------
ACTIVITY 3
As with any attempt at regionalization, biomes
share key characteristics (they are more similar
than dissimilar), however they are not
homogeneous. For example, a polar biome is
characterized by much lower temperatures
than a tropical forest biome. But even within
the polar biome, one can expect a range of
temperatures (generally -40 °C to -4 °C). If
you were high above the ground in a jet you
could identify areas that would appear to be
deserts, forests, or grasslands. You may find it
difficult to determine where one biome begins
and another ends as the two merge into areas
of transition.
Organisms that live in any given biome have
features that have allowed them to adapt to the
environment of that biome. Each biome has
plants and animals that are uniquely qualified
to survive there. Keep in mind there are
species that can survive in a number of
different biomes.
Activity:
Using maps and other reference materials,
students will demonstrate their understanding
of the relationship between biomes and
climate. The students will also identify the
adaptive characteristics or features of plants
and animals representative of the different
biomes.
Materials:
• Biome maps (from textbooks or other
sources)
• Biome Characteristic Chart (attached)
• World atlas
• Large sheets of butcher paper
• Felt pens
Procedure:
1. Based on the number of biomes on the map
you choose to use (usually seven or eight),
divide the class into small discussion
groups and assign each group a different
biome to explore. Distribute a Biome
Characteristic Chart to each student
2. Have each biome group gather data from
the world atlas (or similar sources) about
their biome using the Biome Characteristic
Chan as a guide. This task will require
estimating and generalizing. For example,
the polar biome group will find a range of
temperatures in their defined area. They
should record the range on the Biome
Characteristic Chart. Each group should
complete the chart for their biome.
3. Each group should list the key characteris-
tics of their biome on a sheet of paper and
hang the papers on the chalk or bulletin
board. A spokesperson for each group can
share their information with the class.
4. After all the biome characteristics have
been covered, students should be
encouraged to discuss their findings
through open-ended questions. Examples
of questions:
a. What would the seasonal weather be
like in the different biomes?
b. Do different animals live in different
biomes depending on the time of year
(consider migratory bird species)? How
can they survive in such different
environments?
c. Why are humans able to live in all
biomes?
CLIMATE UNIT
14
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ACTIVITY 3
d. In what ways are humans changing Extensions:
biomes? Have students pick a characteristic plant or
e. Which biome do you currently b've in? animal from any biome and research its life
What do you like/dislike about it? history characteristics. Delineate the plant or
animal's range on a large world map. Is it only
Student Learning Portfolio: found b one biome or does its mclude
1. List of biomes and their characteristics. more ^ Qne biome?
2. Written answers to discussion questions.
Notes:
CLIMATE UNIT 15
-------
ACTIVITY 3
Notes:
CLIMATE UNIT 16
-------
What Is the Relationship Between
Climates and Terrestrial Biomes?
SiuDENiGuiDE—ACTIVITY 3
Definitions of Terms:
Biome: A geographic area characterized by specific kinds of plants
and animals.
Adaption: An inherited trait that increases an organism's chance of
survival in a particular environment
Activity:
Using maps and other reference materials, you
will explore the relationship between biomes
and climate. You will identify the adaptive
characteristics or features of plants and
animals representative of the different biomes.
Materials:
• Biome maps (from your textbook)
• Biome Characteristic Chart
• World atlas
• Large sheets of butcher paper
• Felt pens
Procedure:
1. Your class will be divided into small
discussion groups. Each group will be
assigned a biome.
2. With your biome group, gather data from
the sources your teacher has provided and
fill in the Biome Characteristic Chart for
your assigned biome.
3. Your biome group should list the key
characteristics of your biome on a sheet of
paper. Hang the paper on a chalk or bulletin
board. A spokesperson for your biome
group can share the key characteristics of
your biome with the rest of the class.Q
Notes:
CLIMATE UNIT
17
-------
SiuDENiGuiDE—ACTIVITY 3
Biome Characteristic Chart: For each biome, list the Mowing.
1. Average yearly temperature range:
2. Average yearly precipitation:
3. Soil characteristics:
4. Characteristic vegetation:
5. Characteristic animals:
6. Adaptive features of plants to survive in this biome:
7. Adaptive features of animals to survive in this biome:
C L I M A T E U N I T 18
-------
How Has Earth and Its Climate
Changed Over Time?
ACTIVITY 4
Lesson Focus:
How can the Earth's geologic time scale be used to illustrate the
evolution of life and climate?
Objective:
The student will be able to:
1. Describe the geologic, climatic, and evolutionary changes that
have occurred throughout the Earth's history.
2. Locate major geologic, climatic, and evolutionary events on a
time line chart
3. Construct and interpret a chart of the Earth's history.
Time:
1-2 days
Grade Level:
8-10
Key Concepts:
Past climate, major geologic events, major evolutionary events
Definitions of Terms:
Geologic Time: A term used to describe very
long periods of time, typically measured in
millions of years. It is termed "geologic'' time
because this is the time scale over which slow
geological events can occur (such as mountain
building, changes in the position of continents,
the formation or disappearance of rivers).
Eon: A billion years. The Earth is
approximately 4.5 eons old.
Millennium: A thousand years.
Era: For our convenience, geologic time is
divided into eras of different durations, and
eras are divided into periods. For example, we
are currently living in the Quaternary Period of
the Cenozoic Era. Dinosaurs disappeared at
the end of the Cretaceous Period of the
MesozoicEra.
Plate Tectonics: Hie solid crust of the earth
(including the continents and ocean basins) is
made up of about a dozen major crustal plates
that move across the surface of the Earth due
to the influence of currents in the hot, almost
CLIMATE UNIT
19
-------
ACTIVITY 4
molten mantle (the layer below the oust). The
movement of these plates is responsible for the
slow movement of the continents (continental
drift).
Background:
The oldest rocks known to exist on Earth now
are approximately 3.8 billion years old,
formed probably less than 1 billion years after
the Earth solidified into a planetary body.
Rock of such antiquity is extremely rare. Most
of the earliest rocks have been eroded away or
recycled back into the Earth's core through the
process of plate tectonics, providing scientists
only sparse clues as to the earliest origins and
development of life on Earth. Although these
oldest rocks do not contain clear evidence that
life was present at the time they were formed,
fossil evidence from rocks only slightly
younger (3.4 billion years) suggests that forms
of bacterial life were present and probably
widespread by that time. The processes by
which life first developed are still a mystery.
Although scientists have successfully
simulated certain chemical processes that may
have been necessary precursors to the
development of life, they are far from actually
replicating life's origins in a laboratory.
Although the earliest period of Earth's history
is not well understood, scientists have gathered
sufficient geological, fossil, and radioisotope
evidence to construct a generally clear picture
of the way that Earth's climate and life nave
evolved over the more recent history of the
planet
Although scientists may have gathered enough
data to reconstruct a general outline of Earth's
history, many important questions remain. For
example, why and how do organisms
disappear from the fossil record? Why did
certain groups (such as trilobites and
dinosaurs) disappear abruptly, whereas other
groups faded slowly from the record, and yet
other groups (such as reptiles, sharks, and
certain species of bony fishes) have persisted
through long stretches of geologic time? We
know that Earth's climate has changed
drastically through the millennia; what caused
these changes? How did the changes affect the
Earth's biota?
As humanity becomes increasingly concerned
about the possibility that our activities may be
changing the climate and biota of Earth in
ways we cannot yet understand, it is critical
that we understand the interaction of climate
and life throughout Earth history. In so doing,
we can gain a sense of perspective about our
place in the changes that have occurred on the
planet through geologic time.
Activity:
The students will construct a forty-five foot
long time line chart of the Earth's history on
one continuous sheet of butcher paper. Using
resources available in either the library or
classroom, the students will be researching
geologic and evolutionary events and locating
them on the time line chart
Materials:
• 45-foot long strip of butcher paper
• Felt pens
• Scissors
Procedure:
1. Have the students divide the 45-foot long
strip of butcher paper into four major
divisions as follows. (Starting from left, see
illustration on next page)
CLIMATE UNIT
20
-------
ACTIVITY 4
1C
a. Preeambrian (Pre) Era, which wfll be
39 feet long
b. Paleozoic (Pa) Era, 3 feet long
c. Mesozoic (M) Era, 2 feet long
d. G$nozoic(Q Era, 1 foot long
2. Draw a line separating each era and label
them with the appropriate name.
3. Divide the students into 2-3 person teams
and ask each team to collect materials to
fill in the chart
4. Using resource materials from the library
or classroom, have students research the
major geologic and evolutionary events
that occurred in each era. (Refer to the
Major Events in the Earth's History-see
attached-for some possible events you
might want to include.)
5. Students should record their findings on the
chart If they copied pictures of dinosaurs
etc., they should paste them up in the
appropriate areas on the chart
6. Discuss the chart with the class when done.
For example, ask the students to see where
dinosaurs are on the chart and how long
they existed before they became extinct
Have them identify when humans appeared
and where they fit into the time chart
7. Discuss the Earth's climatic past and how
it has changed throughout its history.
Student Learning Portfolio:
1. Write a short paper on one of the major
events found on the time line chart
2. Identify periods of global climate warming
and cooling on the time line chart and
record in notebooks.
3. Include a photograph or hand drawn
replica of the class time line. The butcher
paper time line could be a permanent
display in the classroom. Students could
earn extra credit throughout the year by
adding materials onto the geologic time
line.
References:
Tlmescale: An Atlas of the Fourth Dimension,
Nigel Odder, 1983.
Environmental Evolution. Edited by Lynn
Margulis and Lorraine Olendzenski, 1992.
Major Events In tte Earth's History.
The following question-and-answer list
represents a small sample of the significant
events that have occurred throughout Earth
history. The events are divided into three
categories, Geologic, Biological, and Climatic.
Hie eras are indicated as follows: Preeambrian
(Pre), Paleozoic (Pa), Mesozoic (M^and
Cenozofc (Ce). Tnc abbreviations T>yr" and
"myr" stand for billions and millions of years
ago, respecti velyQ
CLIMATE UNIT
21
-------
ACTIVITY 4
Notes:
C L I M A T t U N I T 22
A
-------
How Has Earth and Its Climate
Changed Over Time?
SruDENiGuiDE—ACTIVITY 4
Definitions of Terms:
Geologic Time: A term used to describe very long periods of time,
typically measured in millions of years. It is termed "geologic" time
because this is the time scale over which slow geological events can
occur (such as mountain building, changes in the position of
continents, the formation or disappearance of rivers).
.Eon: A billion years. The Earth is approximately 4.5 eons old.
Millennium: A thousand years.
Era: For our convenience, geologic time is divided into eras of
different durations, and eras are divided into periods. For example,
we are currently living in the Quaternary Period of the Cenozoic Era.
Dinosaurs disappeared at the end of the Cretaceous Period of the
Mesozoic Era.
Plate Tectonics: The solid crust of the earth (including the continents
and ocean basins) is made up of about a dozen major crustal plates
that move across the surface of the Earth due to the influence of
currents in the hot, almost molten mantle (the layer below the crust).
The movement of these plates is responsible for the slow movement
of the continents (continental drift).
Activity:
You will construct a 45-foot long time line
chart of the Earth's history on one continuous
sheet of butcher paper. Using resources
available in either the library or classroom,
you will research geologic and evolutionary
events and locate them on the time line chart.
Materials:
• 45-foot long strip of butcher paper
• Felt pens
• Scissors
CLIMATE UNIT
23
-------
1. When was oxygen first
evident on Earth?
Climate Events
3. When did the water
vapor in the atmosphere
first begin to condense
into water and clouds?
Climate Events
5. When did ozone first
appear in Earth's
atmosphere?
Climate Events
7. After the initial warm
phase of the early
Earth, were there other
warm periods?
Climate Events
2. What was the Earth's
first atmosphere like?
Climate Events
4. When did the first ice
age occur?
Climate Events
6. Were there other ice
ages during the during
the Precambrian Era?
Climate Events
8. Were there any ice
ages in the Paleozoic
Era?
Climate Events
-------
SiuDENiGuiDE— ACTIVITY 4
Procedure:
1. Measure and cut a 45-foot long strip of
butcher paper and mount on the wall
around the room or in the hall. Divide the
paper into four major divisions as follows
(starting from left to right):
a. Precambrian Era, which will be 39 feet
long
b. Paleozoic Era, which will be 3 feet long
c. Mesozoic Era, which will be 2 feet long
d. Cenozoic Era, which will be 1 foot long
2. Draw a line separating each era and label
them with the appropriate name.
3. Working in two- or three-person teams
with assignments from your teacher, use
library resources to collect facts about the
important geological and/or evolutionary
events that occurred in the different eras.
Take notes on the events you discover and
include a short description.
4. As a class, write your findings in the
appropriate position along the time line.
Discuss with the class the events you
discovered and tneir significanceQ
Notes:
CLIMATE UNIT
24
-------
9. How long was the
"greenhouse period" in
the Mesozoic era?
Cllmcte Events
10. What happened during
this warming trend in
the Mesozoic era?
Climate Events
11. What was the climate
like at the beginning
of the Cenozoic era?
Climate Events
12. What climatic changes
occurred during the
Cenozoic Era?
Climate Events
13. What caused the
Earth's global climate
to cool?
Climate Events
14. What were the features
of Earth's climate
from 25-15 myr.
Climate Events
15. How did the Earth's
climate change during
the Cenozoic Era?
Climate Events
16. Did ice ages occur in
the Cenozoic Era?
Climate Events
-------
The Earth's atmosphere was
originally composed primarily
of water vapor and CO2 about
4.5 byr. (Pre)
Oxygen first appeared about
1.8 byr as a by-product of the
photosynthesis of primitive
blue/green algae. (Pre)
2.3 byr. (Pre)
The Earth's water and clouds first
formed about 4.4 byr. (Pre)
There is evidence that ice ages occurred
three more times n the Precambrian Era: at
970. 770 and 670 myr. The last one. at 670
myr may have been responsible for a
widespread extinction of algal species.
(Pre)
Ozone first began to develop in the
Earth's upper atmosphere about
1.6 byr. (Pre)
An ice age occurred around 440 myr
(Ordovician period) throughout Africa. Many
fish species were destroyed and trilobites
suffered. A second ice age occurred near the end
of the Paleozoic Era about 360 myr. A third ice
age around 290 myr (Carboniferous period)
ended a coal-making period in the U.S. and
Europe and stoned one between China and
Siberia (see below).
In between the ice ages, the Earth had
several relatively warm periods. The first of
these occurred between 430-60 myr, during
the end of the Ordovician through the
Devonian periods. A second ice age
occurred about 270 myr, during the
Permian period. (Pa)
-------
17. How many ice ages
occurred during the
Cenozoic Era?
Climate Events
19. What caused the ice
ages?
Climate Events
21. What are stromalites
and why are they
important?
Biological Events
23. When did
chloroplasts first
develop?
Biological Events
18. When did the last ice
age occur?
Climate Events
20. When did the earliest
known life-forms
develop?
Biological Events
22. When did the nucleus
first appear in single-
celled organisms?
Biological Events
24. When did multicelled
organisms first
appear?
Biological Events
-------
Flowering plants evolved about 123 myr. In
addition, several climatic changes occurred
throughout this era, causing sea level to rise
and fall several times. (M) Flowering plants
began to displace conifers, ginkgoes, etc.
Insects multiplied, small mammals and birds
evolved. (M)
The greenhouse period of the
Mesozoic era lasted from about
170-117 myr.
Up until 50 myr, the climate was
mild, then it changed. The oceans
cooled by several degrees
Centigrade. The global climate
then vacilated up and down, but
generally cooled. (Ce)
The Cenozoic era opened with an
ice age, resulting in another period
of coal-making in western North
America.
Between 25-15 myr, the Earth's
climate was mild. However,
another ice age occurred about
15 myr (Pliocene Epoch). And
this time, Antarctica went into a
permanent deepfreeze. (Ce)
The rearrangement of the
continents interfered with the
ocean currents'distribution of
warmth (50-40myr). (Ce)
Beginning about 3.5 myr, ice
ages occurred in cycles of about
90,000 years. Initially, they were
not severe but became so about
2.4 myr. (Ce)
The Earth's global climate
switched between cold and mild
many times during the Miocene
Epoch, 25-14 myr. During this
time, the antarctic ice sheets were
the largest ever and worldwide
volcanic activity occurred. (Ce)
-------
25. When did the first
"brain" develop?
Biological Events
27. When did the
mollusks first appear?
Biological Events
29. When did plants first
appear on land?
Biological Events
31. When did the earliest
trees form?
Biological Events
26. What were trilobites
and when did they
first appear?
Biological Events
28. When did the first
fish evolve?
Biological Events
30. When did animal life
first occur on land?
Biological Events
32. When did the first
pine trees (conifers)
exist?
Biological Events
-------
The last ice age ended about 18,000 years
ago. Between 18.000 and 450,000 years
ago, there were at least five major ice
ages, not to mention "false " ice ages. In
between these ice ages were periods of
global warming. (Ce)
Twenty-nine episodes ofglaciation occurred
between 3.25 myr and 550,000 years ago.
The Illinoian Ice Age of 430,000 years ago
went as far south as St. Louis, and evidence
indicates that icebergs existed within the
English channel at this time. (Ce)
The earliest life forms, in the form
of very primitive bacteria,
probably appeared benveen 3.8
and 3.5 byr. (Pre)
Causes of the ice ages include irregular
cycles of the Earth's orbit and gravitational
tugs of the sun and the moon during these
irregular orbits that alter the Earth's tilt on
its axis by a few degrees every 40,000 years.
The first nucleated (nucleus-
containing) cells developed about
1.7 byr. These were similar to
today's molds or fungi. (Pre)
Stromalites are pigmented, plant-like bacteria
that form large colonial structures in shallow
tidal waters. Stromatolite colonies formed
very early in Earth's history and fossil
remains of stromatolites are among the oldest
fossils known (3.5 byr). Living stromatolites
exist today virtually unchanged in appearance
from that of the earliest fossils. (Pre)
The first multicelled organism was
a rype of aquatic plant that
occurred about 1.3 byr. (Pre)
The first true chloroplasts
developed about 1.5 byr. (Pre)
A
-------
33. When did the first
true land animals
evolve?
Biological Events
34. When did the first
major extinction as
recorded by the fossil
record occur?
Biological Events
35. When did winged
insects appear?
Biological Events
37. When did the largest
mass extinction in
Earth's history
occur?
Biological Events
36. When did the first
reptiles evolve?
Biological Events
38. How do scientists
explain this mass
extinction?
Biological Events
39. What happened after
this extinction?
Biological Events
40. When were the
dinosaurs the
dominant vertebrates?
Biological Events
-------
They were segmented, shelled
organisms with eyes that showed
up about 560 myr (Cambrian
Period) and survived successfully
for millions of years. (Pa)
At the very end of the Precambrian Era
and the beginning of the Paleozoic Era,
worms and arthropods were evolving.
These organisms were the first to show
brain-like organs (collections of nerve
cellshabout 600 myr. (Pre and Pa).
"Bony " fish first evolved about
510 myr (end of the Cambrian
Period). The first "jawed "fish
evolved about 425 myr (Silurian
Period). (Pa)
Mollusks first show up in the
fossil record from about 570 myr
(Cambrian Period). (Pa)
About 400 myr (Devonian Period),
certain predatory fish developed
lungs and ventured onto land. (Pa)
Plants evolving from the earliest
blue-green bacteria and algae
first appeared on land about 425
myr (Silurian Period). (Pa)
The first coniferous forests
occurred about 350 myr
(Carboniferous Period). (Pa)
Ancient fern-like trees and forests
developed in swampy areas 410-
370 myr (Devonian Period). (Pa)
-------
41. When did the first
bird-like reptile
evolve?
Biological Events
43. When did the
marsupials (kangaroos,
opossums) evolve?
Biological Events
45. What happened
about 65 myr?
Biological Events
42. When did
monotremes (duckbill
platypus) evolve?
Biological Events
44. When did the
placental mammals
evolve?
Biological Events
46. What happened
during this
extinction?
Biological Events
47. What animals first
appeared in the
Cenozoic Era?
Biological Events
48. When did the New
and Old World
monkeys evolve?
Biological Events
-------
The first major extinction occurred
about 370 myr (Frasnian stage of the
Devonian Period). Some scientists
attribute this and other extinctions to
a cosmic object colliding with Earth.
This catastrophe was followed by the
evolution of amphibians. (Pa)
Millipedes, mites, spiders,
scorpions, and insects such as
springtails were the first to adapt to
carry out their complete life cycle on
land. They did so about 398 myr
(Devonian Period). (Pa)
The evolution of animals like
reptiles onto land occurred about
315 myr (end of Carboniferous
Period). (Pa)
Dragonflies and other winged
insects evolved about 330 myr
(Carboniferous Period). (Pa)
Two theories have been proposed:
1) The development of
supercontinent Pangea and a
subsequent drop in the sea level;
and 2) A collision between Earth
and a large comet. (Pa)
About 245 myr (end of the Permian
Period and the Paleozoic Era), 96%
of all marine species were
destroyed. Reefs and seabeds were
annihilated.
Almost all of the Mesozoic Era,
235-65 myr. (M)
Other creatures evolved, including
mammal-like reptiles called lystrosaurs,
modem corals and squid-like mollusks,
and early flowering plants (bennettitales)
occurred between 245 and 235 myr (early
Triassic Period of the Mesozoic Era).
-------
49. When did grasses
evolve?
Biological Events
51. When did deer and
antelope evolve?
Biological Events
53. When did early
humans evolve?
Biological Events
55. Where did humans
originate?
Biological Events
50. When did humans'
ancestors first evolve?
Biological Events
52. When did orangutans
and baboons evolve?
Biological Events
54. When did humans
first use tools and
fire?
Biological Events
56. When did the modern
horse evolve?
Biological Events
-------
57. When did Homo
sapiens evolve?
Biological Events
59. When did the
Neanderthals exist?
Biological Events
61. When did an and
medicine first
appear?
Biological Events
63. When were calendars
developed?
Biological Events
58. When did wooly
mammoths exist?
Biological Events
60. When did speech and
language begin?
Biological Events
62. When did the modern
humans first evolve?
Biological Events
64. When were livestock
domesticated?
Biological Events
-------
The monotremes evolved before
175 myr (Jurassic Period) in
Australia. (M)
The first bird-like reptile,
Archeopteryx, shows up in the
fossil record about 123 myr
(Cretaceous Period). (M)
About 114 myr (Cretaceous period)
in Mongolia, according to the fossil
record. (M)
The marsupials evolved about 125
myr. (Cretaceous Period). (M)
Plants in western North America
suffered, sea level dropped, and reefs
and many species of marine plants and
animals died out. Small reptiles, birds.
and small mammals survived. (Ce)
The fossil record indicates that a
mass extinction occurred about
65 myr, possibly as a result of a
cosmic object striking Earth.
(Ce)
New and Old World monkeys
evolved about 35 myr, along with
rhinos, pigs, and bears. (Ce)
The ancestors of lions and bears evolved
about 62 myr. (Paleocene Epoch), rodents,
bats, whales, horses, elephants, and
ancient cats and dogs evolved between
55-35 myr. (Eocene and Oligocene
Epochs). (Ce)
-------
Common ancestors of both
humans and the great apes
evolved about 20 myr. (Ce)
Grasses evolved from bamboo-like plants
about 24 myr. It is considered a world-
transforming plant as it heralded a global
change to a cooler, drier time that allowed
for grazing animals to evolve. (Ce)
Orangutans and baboons evolved
about 10-4 myr. (Ce)
Deer and antelope and ancestors
of cows evolved between 19-20
myr. (Miocene Epoch). (Ce)
Stone tools date back to about
2.4-2 myr, but the use of fire isn 't
obvious in the paleontological
record until about 1 myr. (Ce)
Early Australopithecenes evolved
about 4 myr, followed by Homo
habilis 2 myr, and Homo erectus 1.8
myr. (Quaternary Period, Recent
Epoch). (Ce)
The modern horse evolved about
3.7 myr, along with primitive
cattle. The zebra evolved later (2.5
myr). Lions and leopards evolved
about 1.8 myr. (Ce)
Humans originated from Africa
about 3.7 myr. (Ce)
-------
65. When were crops
domesticated?
Biological Events
67. When was the
printing press
developed?
Biological Events
69. When were the
Earth's main
population surges?
Biological Events
71. What are the ages of
the oldest rocks on
Earth?
Geologic Events
66. When did human
civilizations begin?
Biological Events
68. What was the first
important form of
energy use?
Biological Events
70. When were the
earliest continents
formed?
Geologic Events
72. When did the Earth's
moon form?
Geologic Events
-------
Wooly mammoths existed about
J20,000 years ago. (Ce)
Homo sapiens evolved between
600,000 and 200,000 years ago.
(Ce)
Current thinking has complex, modern
speech and language beginning about
43,000 years ago and probably Neanderthal
people had somewhat more limited speech
capacity than modern humans. (Ce)
The Neanderthals (Homo sapiens
neanderthals) evolved about 120,000
years ago and existed for 80,000 years in
Eurasia (longer than the Homo sapiens
sapiens, of which we are members, have
so far existed). Neanderthals were extinct
by about 34,000 years ago. (Ce)
Modern humans evolved about
40,000 years ago. (Ce)
Both art and medicine show up
in the Neanderthal culture
around 60,000 years ago, and
before. (Ce)
Between 12.000-6,500 years ago
dogs, sheep, goats, cows, and
horses were domesticated. (Ce)
Calendars were developed as
early as 35,000 years ago. (Ce)
-------
73. Where did the first
coal deposits form
and how long did it
take?
Geologic Events
75. When did the
supercontinent
Pangea fully form?
Geologic Events
77. When did Pangea
begin to break apart?
Geologic Events
79. When did Earth's magnetic
fields reverse polarity
(North Pole became South
Pole and vice-versa)?
Geologic Events
74. Were other coal
deposits formed?
If so when?
Geologic Events
76. When did the oil
deposits form?
Geologic Events
78. Were any other oil
deposits laid down?
Geologic Events
80. Have the magnetic
reversals stopped?
Geologic Events
-------
Human civilization began about
10,000 years ago. (Ce)
Between 10,600-8,000 years ago,
wheat, rice, and other crops were
domesticated. (Ce)
Steam energy about 1717 A.D.,
followed by the development of
fossil fuels in 1825, and nuclear
energy in 1942.
The printing press was developed
in 1450 A.D.
The earliest continents were first
fonned about 2.8 byr. (Pre)
The Earth's population booms
were in 1000 A.D., 1700,1930,
end the 1960s.
The Earth's moon formed about
4.5 byr. (Pre)
The oldest rocks date back to 3.8
byr. (Pre)
-------
81. What geological
events occurred in
the Cenozoic Era?
Geologic Events
82. Do scientists think there
were any other major
cosmic collisions during
the Cenozoic Era?
Geologic Events
83. When did Australia,
South America,
Antarctica split apart?
Geologic Events
84. Were there other
episodes of volcanic
activity later in the
Cenozoic Era?
Geologic Events
85. When did the
magnetic poles reach
their current
locations?
Geologic Events
-------
Around 270 myr (Permian
Period), other coal deposits were
laid down between China and
Siberia due to tectonic forces. (Pa)
The first coal deposits formed in what is
now Poland, Germany, England,
Pennsylvania, and Kentucky when Europe
and the eastern United States collided. The
collision buried ancient fern forests
between 320-290 myr (Devonian and
Carboniferous Periods). (Pa)
The first group of oil deposits
fanned about 170 myr (Jurassic
Period). (M)
Pangea fully formed about 230
myr. (M)
About 93-85 myr, oil accumulated
at the greatest rate ever from
organic sediments laid down in the
Gulf of Mexico, Venezuela, North
Africa, Saudi Arabia, and Iran.
(M)
Pangea broke apart between
130-40 myr. (M)
The magnetic reversals continue
and the rate of the reversals has
actually increased to about 40
reversals in the most recent 10
myr. (Tertiary and Quaternary
Periods). (Ce)
Before 65 myr, the Earth's poles had
switched only once (between 84-72
myr, end of the Cretaceous Period). In
the 10 myr following the presumed
cosmic impact at 67 myr, the magnetic
reversals occurred 16 times.
-------
Geologic evidence exists to indicate
that another cosmic impact
occurred about 37 myr. (Ce)
The last widespread and intense
episodes ofvolcanism occurred
about 1 myr. (Ce)
The North Atlantic Ocean opened
up, Australia and Antarctica
split, and India slid into Eurasia
between 60-45 myr. (Ce)
These three continents split up
between 35-30 myr (Oligocene
Epoch). (Ce)
About 730,000. (Ce)
-------
What Information Do Paleobotanists
Use to Study Ancient Climates?
ACTIVITY 5
Lesson Focus:
How do paleobotanists use ancient pollen to find out about Earth's
climatic past?
Objective:
The student will be able to:
1. Distinguish the structural differences that are used for pollen
classification.
2. Analyze pollen sample analogs to replicate the way that scientists
gather paleo-data.
3. Interpret pollen sample analogs to replicate how scientists
determine past climates.
Time:
2 class periods
Grade Level:
8-10
Key Concepts:
Past climates, vegetation changes, scientific investigation
Definitions of Terms:
Pollen grain: The microgametophyte of seed
plants; each plant species has pollen grains
with a shape unique to that species.
Paleobotanist: Scientists who study vegetation
of the past
PaleocUmatologist: Scientists who study past
climates.
Palynologists: Scientists who study pollen.
Sediment: Is made up of organic (e.g., dead
algae, dead fish, pollen) and mineral (e.g., soil
erosion deposited from streams) materials that
blanket the bottom of lakes, riverbeds, or
oceans.
Background:
Evidence found in the geologic and plant fossil
records indicates that the Earth's climate has
been very different from today's in the distant
past. There have, however, also been
substantial climatic fluctuations within the last
CLIMATE UNIT
25
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ACTIVITY 5
several centuries, too recently for the changes
to be reflected in the fossil record. These more
recent changes are important to understanding
potential future climate change, and so
scientists have developed methods to study the
climate of the recent past. Although accurate
human-recorded weather records cover only
the last few decades, paleoclimatologists and
paleobotantists have found ways of identifying
the kinds of plants that grew in a given area in
the past, and can infer from the plants what
kind of climate must have prevailed at the
time. Because plants are generally distributed
across the landscape based on temperature and
precipitation patterns, as these climatic factors
changed, the plant communities also changed.
Knowing the conditions the plants preferred,
scientists can make general conclusions about
the past climate.
One way paleobotanists can map plant
distribution over time is by studying the pollen
left in lake sediments by wind-pollinated
plants that once grew in the lake's vicinity.
Sediment in the bottom of lakes is ideal for
determining pollen changes over time because
sediments tend to be laid down in annual
layers (much like trees grow annual rings).
Each layer traps the pollen that sank into the
lake, or was carried into it by stream flow that
year. To look at the "pollen history" of the
lake, scientists collect long cores of the lake
sediment Scientists obtain these samples with
long tubes that are approximately 5
centimeters (cm) in diameter. A series of
casings hold the hole open as the drilling
proceeds. The cores can be 10 m long or
longer, depending on how old the lake is and
how much sediment has been deposited
The core that is removed is sampled every 10-
20 cm and washed in solutions of very strong,
corrosive chemicals such as potassium
hydroxide, hydrochloric acid, and hydrogen
fluoride. This harsh process removes the
organic and mineral particles in the sample,
except for the pollen, which is composed of
some of the most chemically resistent organic
compounds in nature. Microscope slides are
made of the remaining pollen and are
examined to count and identify the pollen
grains. Because every plant species has a
distinctive pollen morphology (called
sculpturing), botanists can identify from which
plant the pollen came.
Through pollen analysis, botanists can
estimate the species composition of a lake area
by comparing the relative amount of pollen
each species contributes to the whole pollen
sample. Carbon-14 dating of the lake sediment
cores gives an approximate age of the sample.
Palynologists can infer the climate of the layer
being studied by relating it to the current
climatic preferences of the same plants. For
example, a sediment layer with large amounts
of western red cedar pollen can be inferred to
have been deposited during a cool, wet
climatic period, because those are the current
conditions to which this species is
There are two reasons that scientists who study
climate change are interested in past climates.
First, by examining the pattern of plant
changes over time, they can determine how
long it took for plant species to migrate into or
out of a given area due to natural processes of
climate change. This information makes it
easier to predict the speed with which plant
communities might change in response to
CLIMATE UNIT
26
-------
ACTIVITY 5
human-induced climate change. Second, by
determining the kinds of plants that existed in
an area when the climate was wanner than at
present, the scientists can more accurately
predict which plants will be most likely to
thrive if the climate warms again.
Activity:
Students will examine pictures of pollen grains
representing several different species, showing
the structural differences that scientists use for
identification. Students will analyze model soil
samples with material mixed in to represent
pollen grains. They will determine the type
and amount of the "pollen" in the samples and,
based on information provided to them, will
determine the type of vegetation and the age of
their samples and will make some conclusions
about the likely climate at the time the pollen
was shed.
Materials:
1. Pictures of several types of pollen
(attached page 34) (Note to Teacher: An
excellent example of different pollen types
is found in the October 1984 issue of
National Geographic on p. 492-493.)
2. One large graduated cylinder (1000 mL at
least) for the "sediment" column
3. Five different types of "sediment" (any
soil, sand, potting mixture, etc. that can be
layered to show five distinct layers. You
will need enough for the sediment column
and the corresponding "samples")
4. Small, resealable plastic bags
5. Pie tins (one for each sediment sample)
6. Eleven different colors of paper "dots"
(from a hole punch) to serve as pollen
analogs
CLIMATE UNIT
7. Key to the different "pollen" colors
showing which colors represent which
plants, and information about the climatic
requirements for each plant species
8. Worksheets (provided)
Procedure:
Plants have pollen with unique morphology
that can be used to identify them.
Ask the students to carefully examine the
pictures of the different pollen types, noting
the structural differences in each type. Discuss
those differences, and how scientists can use
those to identify the plants from which they
were shed.
Analysis of pollen data gives evidence of
paleoclimate.
Note to Teacher: The following exercise was
developed based on actual pollen data
collected from a lake in southwest Washington
State. Other regions of the country may have
similar pollen records available. The botany
departments of local universities may be able
to give you information on locally relevant
pollen data that you can adapt to this exercise.
1. Layer five different kinds of soil (garden
soil, sand, fine gravel, potting mixture, peat
moss, vermiculite, perlite, or similar
material) into the graduated cylinder so
they form five distinct layers. This
represents the sediment core with which
the students will work. Label the layers
with their respective ages as shown in
Figure 1.
2. Choose eleven different colors of paper to
represent the "pollen" grains. Note to
Teacher: We have suggested colors (Tables
1 and 2); however, you can make your own
27
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ACTIVITY 5
color choices. To avoid confusion later,
make certain you note any color changes
on both Tables I and 2.
3. Make the different color pollen grains by
using the "dots" from a standard hole
punch.
4. "Sediment" samples. Prepare one sample
for each pair of students. It is important to
make certain that all five layers of your
sediment core are represented
5. Fill the resealable plastic bags with
approximately 100 mL of the same
material representing a sediment layer in
the core. For
example, if you
have sand
representing Layer
1 in the sediment
column, place 100
mL of sand in a
plasticbag. If you
chose a dark soil
for Layer 2, place 100 mL of dark soil in a
second plastic bag and so on until of 5
layers in the column have corresponding
samples. Replicate until you have enough
samples to distribute one to each pair of
students.
6. Using Table 1 as a guide, place into each
sample bag approximately 25 paper dots to
represent the pollen found in that layer.
7. Begin by showing the sediment column
and discussing the way that sediment is laid
down in lakes, how it traps pollen, and how
scientists obtain the lake sediment cores.
8. Hand out one sediment sample, a pie tin,
and a worksheet to each pair of students.
Explain that each sample contains "pollen"
from the species prevalent at the time of
deposition. Students should empty the
contents of their sample into a pie tin. Their
task is to sift through the sample to separate
out the pollen from the sediment,
determine from a key (Table 2) what
species of plants are represented and what
percentage of the total pollen comes from
each species.
9. If more than one pair of students worked
on any sediment layer, ask them to get
together and come to a consensus on what
plants they've found and the relative
abundances. The worksheet can be used to
keep track of the percentage of plants
found in each layer. From the key (Table 2)
have them come to a consensus on what
the climate must have been like at the time
of deposition.
10. Ask each group studying a sediment layer
to report their conclusions to the class, then
as a class build a consensus on the pattern
of climate change represented by this
sediment column. Students can complete
their worksheets with data provided by
students studying different sediment layers.
11. Once a class consensus has been reached,
you may wish to share the interpretation of
Dr. Cathy Whitlock, the paleoclimatologisl
that did the research this exercise is based
on, with the class. The general conclusions
of her paper and a map showing the area
studied is provided in the attached
summary 'The Paleoclimate of Battle
Ground Lake, Southern Puget Trough",
Washington.
Note to Teacher: Ask the students to
carefully replace the pollen in the sample
bags. These samples can be used again.
CLIMATE UNIT
28
-------
ACTIVITY 5
Student Learning Portfolio:
1. Pollen grain drawings in log
2. Log entry on age/type of pollen in soil
sample, and how it relates to climate
3. Completed worksheets
Extensions:
The extensions can be focused on further
exploration of the role of pollen analysis in
paleoclimate studies, on further student interest
in the sculpturing of pollen itself, or on the role
of pollen as an allergen. Possibilities are listed
below.
1. Discuss some possible difficulties with
obtaining sediment cores (tippy boats, bad
weather, having the hole you've been
drilling fill before you're done, etc.).
2. Discuss some reasons why most lake
sediments can only tell you about
vegetation hundreds or thousands of years
ago (not millions). Possible answers-lakes
aren't that long-lived, glaciers, mountain
building, etc. will destroy lakes, sediment
will eventually fill lakes completely.
3. Provide students with prepared pollen
slides, or have students collect and mount
their own pollen on sb'des for examination
under a microscope. Ask them to sketch the
different pollen types and produce their
own identification key to pollen.
Figure 1. Model Sedment Column
Present
4,500 years ago
9,500 years ago
11,500 years ago
15,000 years ago
20,000 years ago
CLIMATE UNIT
29
-------
ACTIVITY 5
Table 1. Paper Dots and Amounts to Be Used to Make Up Each Sediment Sample
(In the sediment age designations, ybp = years before present)
Sediment
Layer
5
(4,500 ypb
to present)
4
(4.500 ybp
to 9,500 ybp)
3
(9.500 ybp
to 11. 200 ybp)
2
(11, 200 ybp
to 15.000 ybp)
1
(15.000 ybp
to 20.000 ybp)
Plant
Species
Cedar
Hemlock
Douglas Fir
Alder
Douglas Fir
Oak
Mixed Meadow Species
Douglas Fir
Grand Fir
Alder
Lodgepole Pine
Englemann Spruce
Grand Fir
Grasses & Sedges
Alpine Sagebrush
Grasses & Sedges
Alpine Sagebrush
Lodgepole Pine
Englemann Spruce
Dot
Co'cr
Dark Blue
White
Brown
Red
Brown
Bright Yellow
Light Yellow
Brown
Pink
Red
Light Blue
Light Green
Pink
Dark Green
Cream
Dark Green
Cream
Light Blue
Light Green
Number
of Dots
6
5
10
4
3
3
19
7
5
13
7
3
3
9
3
15
4
4
2
Percentage
of Total
25%
20%
40%
15%
10%
10%
80%
30%
20%
50%
30%
15%
15%
30%
10%
60%
15%
15%
10%
CLIMATE UNIT
30
^^~^
-------
ACTIVITY 5
Table 2. Pollen Key and Climatic Characteristics of the Vegetation
Dot Color
White
Brown
Dark green
Red
Pink
Light Green
Dark Blue
Light Blue
Light Yellow
Dark Yellow
Cream
Species
Western
Hemlock
Douglas
Fir
Grasses
& Sedges
Alder
Grand Fir
Englemann
Spruce
Western
Red Cedar
Lodgepole
Pine
Mixed
Meadow
Species
Oak
Alpine
Sagebrush
Climatic Characteristics
Prinicipal dominant tree of many lowland, temperate sites. Requires very
moist, temperate conditions for growth.
Broadly distributed throughout Pacific Northwest from moderately cool to
warm sites. Grows best under temperate, somewhat moist conditions.
This pollen from grasses and sedges typically found in very cool alpine/
subalpine meadow sites characterized by very cool summers, harsh
winters, and short growing seasons.
Widespread throughout Northwest, often colonizing gravel bars or other
poor soils, prefers abundant water and can grow in cool climates.
Found at mid-elevations in Cascade mountains. Grows in cool climates.
but not as cold tolerant as trees found at higher altitudes.
Found in cold, usually subalpine sites. It is an important timberline species
in the Rocky Mountains.
Found only in temperate, very moist climates.
Found in areas of very cool climates typically growing on poor soils, often
at high altitudes (above 3,500 feet) under the present climate.
This pollen is Typical of a mixture of herbaceous plants common to warm-
temperate meadowlands, such as may be found in the Willamette Valley in
Oregon. Typically, these species grow in areas of warm summer
temperatures and summer drought
Found in warm-temperate sites characterized by dry, warm summers,
such as can be found today from Oregon's Willamette Valley south
into California.
Woody, low-growing shrub related to the sagebrush of eastern Washington
Oregon. Found only at high-altitude, cold sites.
CLIMATE UNIT
31
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ACTIVITY 5
The Paleoclimote of Battle Ground Lake,
Southern Puget Trough, Washington
State:
The research site is located 30 km north of the
Columbia River, in Clark County Washington,
near the town of Battle Ground (Figure 2). The
lake has been in existence for at least the last
20,000 years, and has continuously
accumulated sediments through most of that
time. Trapped in the sediments are pollen
grains from the plants that grew in the general
vicinity of the lake at the time the sediments
were deposited. By examining the pollen in
different layers of sediment from the bottom
layer to the top, we can reconstruct the
vegetation changes that have occurred in the
area during the lake's existence. Because we
know something about the climatic conditions
that the plants needed to survive, we can use
the vegetation data to reconstruct the past
climate in the area for the entire 20,000 year
period.
Many layers have been identified by
paleociimatologists. For simplicity sake, we
Figure 2.
Washington
Battle Ground Lake
•Vancouver
CLIMATE UNIT
will combine these into five major layers. The
age of each layer has been established by
radiocarbon dating and by reference to
volcanic ash layers of known age from Mt St.
Helens and from the explosion of Mt. Mazama
(now Crater Lake in Oregon).
Loyertl: 20,000-15,000 Years Before
Present (ybp):
Glacial maximum, with nearly a vertical mile
of ice over the site of Seattle, and the
continental glaciers extending south of the
present site of Olympia. An alpine glacier from
ML St. Helens extended down the Lewis River
Valley to within 30 km of the lake site. The
lake area climate was cold, with a short
growing season. The landscape resembled an
arctic/alpine tundra, with the meadows
dominated by alpine grasses/sedges, low
woody shrubs, and scattered tree islands of
cold-tolerant Engelmann spruce and lodgepole
pine.
Layer #2:15,000 -11,200 ybp:
Glaciers have begun to recede as the climate
starts a warming trend. Although still cold in
comparison to the present climate, the
warming has progressed enough to cause the
tundra vegetation to begin to be replaced by
more extensive forests of lodgepole pine,
Engelmann spruce, and grand fir in an open
woodland setting. Further north in the northern
and central Puget Lowland, many new areas
have been opened up to plant colonization by
the glacial recession, and lodgepole pine has
invaded these new areas.
Layer #3:11,200 -9,500 ybp:
The warming continues and the first
occurrence of "modem", temperate coniferous
forest is found in this period as Douglas-fir,
32
>flH
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ACTIVITY 5
alder, and grand fir dominate in forests not
unlike those that occur today. The climate is
similar to today's climate as well.
Layer #4:9,500 -4,500 ybp:
The climate continues to warm with mild,
moist winters and warm, dry summers
predominating. The forests of the previous
period (which needed cooler, moister
conditions) disappear to be replaced by more
drought-adapted mixed oak, Douglas fir, and
dry meadowland community. Today such
vegetation is typical of areas of the Willamette
Valley of Oregon that have escaped
cultivation.
Layer #5:4,500 ybp -Present:
A cooler and moister period than the previous
one. The dry-land vegetation is replaced by the
extensive closed coniferous forests seen today,
with hemlock and western -:d cedar
dominating the areas of forest undisturbed by
logging.
Reference:
Bamosky, C. W. 1985. Late Quaternary
vegetation near Battle Ground Lake, southern
Puget Trough, Washington. Geological Society
of America Bull. 96: 263-27 l.Q
CLIMATE UNIT
33
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ACTIVITY 5
Several Types of Pollen
Alder
Sweet Gum
Scale in Microns
Pollen grain illustration courtesy of Allen M.
Solomon, U.S. Environmental Protection
Agency, Corvallis, Oregon 97333.
CLIMATE UNIT
0
I
30
60
Scale in Microns
34
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What Information do Paleobotanists
Use to Study Ancient Climates?
SiuDENiGuiDE—ACTIVITY 5
Definitions of Terms:
Pollen grain: The microgametophyte of seed plants; each plant
species has pollen grains with a shape unique to that species.
Paleobotanist: Scientists who study vegetation of the past.
Paleoclimatologist: Scientists who study past climates.
Palynologists: Scientists who study pollen.
Sediment: Is made up of organic (e.g., dead algae, dead fish, pollen)
and mineral (e.g., soil erosion deposited from streams) materials that
blanket the bottom of lakes.
How do paleobotanists use ancient pollen to
find out about Earth's climatic past?
Activity:
You will analyze sediment samples with other
material mixed in to represent pollen grains,
determine the type and amount of the "pollen"
in the samples. From this information, you will
determine the type of vegetation and the age of
the samples and will present conclusions about
the likely climate at the time the pollen was
shed.
Materials:
1. Samples of sediment containing colored
paper dots to represent pollen
2. Pie tin
3. Key to the different "pollen" colors
showing which colors represent which
plants, and information about the climatic
requirements for each (Table 1, page 38)
CLIMATE UNIT
4. Worksheet (your teacher will hand out)
Procedure:
The following exercise was developed based
on actual pollen data collected from a lake in
southwest Washington State.
1. Your teacher will first show you a model
sediment core containing five separate
layers, each laid down at a different time in
the past Pay attention to the color and
texture of each layer to help you identify
the samples from each layer you will be
working with.
2. Each pair of students will be given a
sediment sample, a pie tin, and a
worksheet Each sample contains "pollen"
(actually colored paper dots representing
pollen, with each color representing pollen
from a different species of plant) from
35
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SiuDENiGuiDE—ACTIVITY 5
plants that grew in the area at the time the
sediment was deposited.
3. Your and your partner will separate out the
pollen from the sediment. Empty the
sediment into the pie tin. Sift and dig until
you have found all of the pollen grains.
Keep the pollen grains separated by color.
4. Use the pollen key (Table 1, page 38) to
determine what species of plants are
represented in your sample and what
percentage of the total pollen comes from
each species. Fill in the worksheet for the
sediment layer you are working on.
5. Use the pollen key also to figure out what
the climate was when your layer was
deposited (use the climate information
given with each species description to do
this). Be sure to compare your sediment
sample to those in the entire sediment core
so that you know what level your sample is
from and how old it is.
6. Compare your conclusions with others in
your class who were assigned the same
sediment layer. Do you all find the same
plant types? Do you all agree on the
climate that probably existed at the time?
7. With your class, discuss the species of
plants found in each layer and the climate
that probably existed at the time. Fill in the
rest of your worksheet with the information
provided by other students who studied
different sediment layers. Can you
determine what the overall pattern of
climate change was during these last
20,000 years? Can you speculate about
what might have caused the changesTQ
Notes:
CLIMATE UNIT
36
-------
o
Activity 5 Worksheet - Plant Species
c
z
Sediment
Layer
1
2
3
4
5
Western
Hemlock
Douglas
Fir
Grasses
and
Sedges
Alder
Grand
Fir
Engle-
mann
Spruce
Western
Red
Cedar
Lodge-
pole
Pine
Mixed
Meadow
Species
Oak
Sage-
brush
e/>
c
o
m
Z
0
c
6
m
I
O
-4
<
Ol
o>
-------
SruDENiGuiDE—ACTIVITY 5
Table 1. Pollen Key and Climatic Characteristics of the Vegetation
Dot Color
White
Brown
Dark green
Red
Pink
-
Light Green
Dark Blue
Light Blue
Light Yellow
Dark Yellow
Cream
Species
Western
Hemlock
Douglas
Fir
Grasses
& Sedges
Alder
Grand Fir
Englemann
Spruce
Western
Red Cedar
Lodgepole
Pine
Mixed
Meadow
Species
Oak
Alpine
Sagebrush
Climatic Characteristics
Prinicipal dominant tree of many lowland, temperate sites. Requires very
moist, temperate conditions for growth.
Broadly distributed throughout Pacific Northwest from moderately cool to
warm sites. Grows best under temperate, somewhat moist conditions.
This pollen from grasses and sedges typically found in very cool alpine/
subalpine meadow sites characterized by very cool summers, harsh
winters, and short growing seasons.
Widespread throughout Northwest, often colonizing gravel bars or other
poor soils, prefers abundant water and can grow in cool climates.
Found at mid-elevations in Cascade mountains. Grows in cool climates.
but not as cold tolerant as tries found at higher altitudes.
Found in cold, usually subalpine sites. It is an important timberline species
in the Rocky Mountains.
Found only in temperate, very moist climates.
Found in areas of very cool climates typically growing on poor soils, often
at high altitudes (above 3,500 feet) under the present climate.
This pollen is typical of a mixture of herbaceous plants common to warm-
temperate meadowlands, such as may be found in the Willamette Valley in
Oregon. Typically, these species grow in areas of warm summer
temperatures and summer drought
Found in warm-temperate sites characterized by dry, warm summers,
such as can be found today from Oregon's Willamette Valley south
into California.
Woody, low-growing shrub related to the sagebrush of eastern Washington
Oregon. Found only at high-altitude, cold sites.
CLIMATE UNIT
38
-------
What Is a Greenhouse and How Does
It Trap Heat from the Sun?
ACTIVITY 6
Lesson Focus:
What is a greenhouse and how does it trap heat from the sun?
Objective:
The student will be able to:
1. Explain that greenhouses are composed of a clear physical barrier
that allows visible light energy to enter, but blocks the escape of
heat energy.
2. Demonstrate through data collection how visible light trapped in
a model greenhouse will cause the temperature to rise.
3. Compare and contrast the processes affecting the heat balance of
a green house and the processes affecting the heat balance of the
earth.
Time:
1 class period
Grade Level:
8-10
Key Concepts:
Greenhouse effect, prediction, data collection, experimentation
Definitions of Terms:
Visible Light: Light in the area of the
electromagnetic spectrum that can be seen
with human eyes, generally extending from
violet light (shorter wavelengths) to red light
(longer wavelengths).
Infrared Radiation: Although it can not be
seen by the human eye, most objects absorb
and emit infrared radiation. The infrared
portion of the electromagnetic spectrum has
longer wavelengths than visible light. It is also
known as heat radiation.
Trace Gases: Gases in Earth's atmosphere that
make up a very small pan of the total
atmospheric composition. Important trace
gases include water vapor, carbon dioxide
(CO2), methane (CH4), and others.
Greenhouse Effect: The atmospheric
phenomenon responsible for the Earth being
warm enough to sustain life as we know it
GREENHOUSE EFFECT UNIT
39
-------
ACTIVITY 6
Trace gases in the atmosphere trap heat near
the Earth's surface before it has a chance to
escape into space. These gases are responsible
for keeping the Earth's average temperature
above freezing.
Background:
Greenhouses are used extensively by botanists,
commercial plant growers, and dedicated
gardeners. Particularly in cool climates,
greenhouses are useful for growing and
propagating plants because they both allow
sunlight to enter and prevent heat from
escaping. Because they are covered with a
transparent material, visible light from the
outside can enter the greenhouse unhindered.
Absorbed by the material inside the
greenhouse, this visible light serves to warm
the interior. The heat is prevented from leaving
the greenhouse by the transparent covering,
which serves to prevent outside winds from
carrying the heat away, and which serves to
reflect the heat energy back into the interior.
In some ways like the greenhouse covering,
our atmosphere also serves to retain heat at the
surface of the Earth. Much of the sun's energy
reaches the Earth as visible light. Of the visible
light that enters the atmosphere, about 30% is
reflected back out into space by clouds, snow
and ice-covered land and sea surfaces, and by
atmospheric dust The rest is absorbed by the
liquids, solids, and gases that constitute our
planet. The energy absorbed will eventually be
reemitted, but not as visible light (Only very
hot objects such as the sun can emit visible
light). Instead, the energy will be emitted as
longer-wavelength light called infrared
radiation. It is also called "heat" radiation,
because although we cannot see in infrared,
we can feel it's presence as heat This is what
you feel when you put your hand near the
surface of a hot skillet Certain gases in our
atmosphere (known as "trace" gases because
they make up only a tiny fiaction of the
atmosphere) can abscib this outgoing infrared
radiation, in effect trapping the heat energy.
This trapped heat energy makes the Earth
warmer than it would be without these trace
gases.
The ability of certain trace gases to be
relatively transparent to incoming visible light
from the sun, yet opaque to the energy radiated
from the earth is one of the best-understood
processes in atmospheric science. This
phenomenon has been called the "Greenhouse
Effect" because the trace gases function to trap
heat similar to the way that the transparent
covering of a greenhouse traps heat. Without
our atmospheric greenhouse effect, the surface
temperature of the Earth would be far below
freezing. On the other hand, an increase in the
amounts of these trace gases in the atmosphere
could result in more heat being trapped and
cause increasing global temperatures.
Even apparently small increases in global
temperature can cause major changes in global
climate. For example, during the height of the
last great ice age (which ended 10,000 to
12,000 years ago), the average global
temperatures were only 5 °C (9 °F) lower than
they are today. If global average temperatures
rise by as little as 2 °C (3.4°F), the planet
would be warmer than any time in human
history.
Activity:
Students will measure, record, and graph the
temperature differences between intact and
perforated model greenhouses.
GREENHOUSE EFFECT UNIT
40
-------
ACTIVITY 6
8. Discuss the results, develop some
possible explanations (examples—the
vents let cool air in). Relate the plastic
greenhouse to big glass greenhouses,
and then relate it to the Earth as the
biggest greenhouse. Figure 3 is a
representation of the Greenhouse
Effect
Caution: The analogy between the plastic
cover and the atmosphere is not a perfect
one. Greenhouse covers prevent heat
losses from convection (air movement
carrying away the heat) as well as by
radiation (direct transfer of heat energy).
The atmosphere prevents only heat loss by
radiation. The greenhouses used in this
activity serve as a crude model of the
actual atmospheric process and are only of
limited use in understanding the nature and
scope of the actual Greenhouse Effect
Student Learning Portfolio:
1. Construct a graph of temperature
changes in the greenhouses. Each
student should have a graph for their
logbook.
2. Write an explanation of greenhouse
warming.
3. Draw a diagram of Earth's greenhouse
(possibly a simple picture of Earth, sun,
light from the sun, and the atmosphere
as a greenhouse cover). Student's
develop their own, based on
discussion—not just a copyD
Outfotaf Energy
(inftvedhett)
Incoming Energy
(viiibfc li|hi)
Figure 3. The Greenhouse Effect
GREENHOUSE EFFECT UNIT
42
-------
ACTIVITY 6
Experimental Chamber Construction:
Clear bottles with removable opaque bases
(Figure A) are ideal for these activities,
however, their availability is limited in some
parts of the country. If these bottles are limited
in your area, the one-piece bottles will also
work (Figure B). The following information is
intended to assist you in preparing the bottles
for use.
1. Two-piece bottles. Remove the bottle label
by soaking in warm water. Fill the bottle
with warm water to soften the glue holding
the base. After a few minutes you can
easily separate the base from the bottle. Set
the base aside for future use. Cut off the
end of the bottle approximately 1 inch
from the bottom and discard the bottom
piece (Figure C). Place the bottle in the
plastic base and the experimental chamber
is ready for use.
2. One-piece bottle. Remove the bottle label
by soaking in warm water. It will be
necessary to find a 14-16 oz. plastic
container at least 4-1/2 inches in diameter
at the top (sour cream, cottage cheese, and
salsa containers work well) to serve as the
base for the chamber. Cut the end of the
bottle off approximately 2 inches from the
bottom and discard the bottom piece
(Figure C). Place the bottle in the plastic
base and the experimental chamber is
ready for use.
Figure A.
Figure B.
soda bottle base food container
Figure C.
GREENHOUSE EFFECT UNIT
43
-------
ACTIVITY 6
Notes:
GREENHOUSE EFFECT UNIT 44
-------
What Is a Greenhouse and How Does
It Trap Heat from the Sun?
SiuDENiGuiDE—ACTIVITY 6
Definitions of Terms:
Visible Light: Light in the area of the electromagnetic spectrum that
can be seen with human eyes, generally extending from violet light
(shorter wavelengths) to red light (longer wavelengths).
Infrared Light: Although it can not be seen by the human eye, most
objects absorb and emit infrared radiation. The infrared portion of the
electromagnetic spectrum has longer wavelengths than visible light.
It is also known as heat radiation.
Trace Gases: Gases in Earth atmosphere that make up a very small
part of the total atmospheric composition. Important trace gases
include water vapor, carbon dioxide (CO2), methane (CH4), and
include
others.
Greenhouse Effect: The atmospheric phenomenon responsible for
the Earth being warm enough to sustain life as we know it. Trace
gases in the atmosphere trap heat near the Earth's surface before it
has a chance to escape into space. These gases are responsible for
keeping the Earth's average temperature above freezing.
Activity:
You will make model greenhouses. Using the
models, you will measure, record, and graph
the temperature differences between intact and
vented model greenhouses.
Materials:
For each team of four students:
• Two experimental exposure chambers
• Knife or scissors
• Tape
• Two thermometers
• One 150-watt floodlight
GREENHOUSE EFFECT UNIT
• Clamp-on, portable reflector lamp
• Stand for lamp setup
• Graph paper
Procedure:
1. With your team, prepare two
soda-bottle "experimental
exposure chambers". Use
scissors to cut several
elongated vents (1x4
inches) in the sides of one of
the bottles (Figure 1). Leave
the second bottle intact
F=l
Figure 1.
45
-------
SiuoENTGuiDE—ACTIVITY 6
2. Tape a thermometer (using cellophane tape
or light-colored masking tape, not black
electrical tape) to the sides of each bottle
(facing out). Make sure the bulb of the
thermometer is just above the top of the
opaque base (if the bulb is below the base,
the thermometer may record the heat
absorbed directly by the dark plastic, and
complicate the results). Also make sure that
the two thermometers are reading the same
temperature. If not, you can take that into
account by recording the difference and
adjusting for the difference when the
observations are made. For example, if
thermometer A reads 22 °C and
thermometer B reads 23 °C when they both
should read the same, you can either add
1 °C to every reading of A or subtract 1 °C
from every reading of B to correct for the
difference. Cap the bottles.
3. Set up a graph of time (in minutes) versus
temperature upon which to record your
observations. The temperature axis should
be approximately 20 °C to 40 °C. Which
bottle do you think will get hotter? Why?
Record your prediction in your logbook.
4. Place both bottles
approx. 6" away
from the lamp with
the thermometers
facing away from
the light (Figure 2).
5. Each of you
should have
a specific
responsibility
during the
experiment.
For each of
your bottles,
one of you
should keep
track of the
time and the Figure 2.
other should record the temperature every
two minutes on your graph.
6. Turn on the light and begin collecting your
data. Continue the experiment for 20
minutes.
7. Compare the graphed data from the vented
bottle and the intact bottle. What
happened? How do you explain your
observations?Q
Notes:
GREENHOUSE EFFECT UNIT
46
-------
What Factors Influence a Greenhouse?
ACTIVITY 7
Lesson Focus:
What factors affect the heat-trapping ability of a greenhouse?
Objective:
The student will be able to:
1. Identify at least three factors affecting the heat-trapping ability of
a greenhouse, including transparency of the greenhouse cover,
color of the surfaces inside the greenhouse, and the type of
surface inside.
2. Record observed temperature data in graph form.
3. Explain the factors important in earth's greenhouse through a
diagram.
Time:
2 class periods
Grade Level:
8-10
Key Concepts:
Greenhouse effect, prediction, data collection, experimentation
Definitions of Terms:
Albedo: The percentage of solar energy
reflected back by a surface. In the atmosphere,
clouds reflect solar energy into space as visible
light. At the Earth's surface, light-colored land
(i.e., deserts, snow and ice fields) and sea
surfaces also reflect solar energy back into
space.
Feedback: A process in which part of the
output of a system is fed back to another part
of the system. Feedback generally serves as an
internal control on what goes on in a system.
Positive feedback can encourage more of what
is already happening; negative feedback will
discourage what is happening. In the case of
global climate change, positive feedback
would act to increase global warming while
negative feedback would act to reduce it
Background:
The amount of solar radiation absorbed by the
atmosphere and surfaces of the earth, and
hence the amount of global warming, is
strongly influence by several factors. These
factors include:
1. Clouds: Depending on their altitude and
optical properties, clouds may serve to
GREENHOUSE EFFECT UNIT
47
-------
ACTIVITY 7
either cool or warm the Earth. Many types
of clouds (notably large, thick, relatively
lower altitude clouds such as cumulus and
cumulo-nimbus types) significantly reflect
incoming solar radiation, thereby increasing
earth's albedo, or reflectivity, and serve to
reduce solar warming of the surface. The
whitewash on greenhouses has the same
effect on a smaller scale. However, high-
altitude, thinner clouds such as cirrus types
act primarily to absorb long-wave radiation
from the earth's surface, causing increased
warming. If global temperatures are indeed
on the rise, one of the likely consequences
is increased surface water evaporation. The
scientific community is uncertain whether
increased evaporation will result in more
cloud formation, and if so, what type of
clouds would form. These are clearly
critical questions to answer as scientists
attempt to predict the future global climate.
2. Surface Albedo: Just as some clouds reflect
solar energy into space as visible light, so
do light-colored land and sea surfaces. This
surface albedo strongly influences the
absorption of sunlight. Snow and ice-cover
is highly reflective, as are light-colored
deserts. Large expanses of reflective
surfaces can significantly reduce solar
warming (white sand in a model
greenhouse has the same effect). If global
temperatures increase, snow and ice cover
may shrink. The exposed darker surfaces
underneath may absorb more solar
radiation, causing further warming. This is
an example of a "positive-feedback"
mechanism. Scientists are uncertain as to
the importance and magnitude of the
feedback and it is currently a matter of
serious scientific study and debate.
GREENHOUSE EFFECT UNIT
3. Oceans: Water has the capacity to store and
transport large amounts of heat energy.
(The model greenhouse with standing
water demonstrates this in the activity
below.) Thus, because of their enormous
size and depth, the Earth's oceans are
extremely important in determining global
heat exchange and, hence, global climate.
In addition, oceans are an important sink
for atmospheric CO2, and their ability to
absorb CO2 is strongly related to ocean
temperature. Thus, oceans are important in
determining the future rate of increase in
atmospheric CO2, as well as influencing the
rate of global temperature change. To date,
scientists do not have sufficient information
to quantify the ocean's eilect on the
atmosphe.e and the climate, but significant
scientific efforts are under way to do so.
Activity:
Students will set up a selection of model
greenhouses with different properties and will
observe, record, and graph the differences in
temperature between them. Students will
brainstorm possible reasons for the observed
differences.
Materials:
For each team of four students:
• Four soda bottle "experimental chambers"
(see page 43 in Activity 6)
• Four thermometers
• White paint
• 3 Cups of soil (garden soil or potting soil)
• 1.5 Cups of white sand or perlite
• One 150-watt floodlight bulb
• Clamp-on, portable reflector lamp
• Stand to support lamp setup
• Graph paper
48
-------
ACTIVITY 7
Procedure:
Greenhouse Assembly
Note to Teacher: To save time, you (or your
students) should prepare the model
greenhouses prior to class. For each team of
four students, you will need to use four
experimental chambers. If there are holes in
the bases of the experimental chambers, they
should be sealed. This can be done using tape
or silicon seal. At least one of the bases should
be sealed to be able to hold water (silicon seal
works well). Paint the upper 1/3 of one of the
bottles white.
1. Divide the class into small teams
(four students) and distribute materials.
Figure 1. Experimental Chambers Simulating
Different Factors That Influence
Climate
A B
Paint upper
1/3 white
Dark soil in base A and B
GREENHOUSE EFFECT UNIT
2. Each team should have four experimental
chambers (two regular, one that can hold
water, and one that is partially painted
white). The students should label the
bottles A, B, C, and D, with bottle B having
the white paint and bottle D having the
sealed base to hold water.
3. Have students fill the base of bottles A and
B with soil, bottle C with white sand, and
bottle D with room-temperature water. The
greenhouses are now ready (Figure 1).
D
White sand
in base
Room temperature
H2O in base
49
-------
ACTIVITY 7
4. The suidents will tape a thermometer
(using cellophane tape or light-colored
masking tape, not black electrical tape) to
the sides of each bottle (facing out). They
should make sure the bulb of the
thermometer is just above the top of the
opaque base (if the bulb is below the base,
the thermometer may record the heat
absorbed directly by the soil or water, and
complicate the results). It is important that
the thermometers are all reading the same
temperature before beginning the
experiment. If not, explain how they can
"zero" them by recording the difference
and adjusting for the difference when the
observations are made. The bottles should
be capped.
5. Have each team set up a graph of time (in
minutes) versus temperature upon which to
record their observations. The temperature
axis should be approximately 20 °C to
40 °C. Ask them to predict which bottle
they think will get hotter? Why? Record
predictions in their logbook.
6. Each student should have a specific
responsibility during the experiment (either
by keeping track of the time or recording
the temperature for the different bottles).
7. Place the bottles approximately 6" away
from the lamp with the thermometers
facing away from the light
8. Have students turn on the light and begin
recording the temperatures every two
minutes. Continue for at least 20 minutes.
9. Discuss the results and propose some
possible explanations. Relate the factors
affecting the model greenhouse to the
factors affecting the "global greenhouse".
Student Learning Portfolio:
1. Graph temperature changes in the
greenhouses for different surface
characteristics and albedos. Each student
should have a graph for their logbook.
2. Write an explanation of the effect of albedo
and surface type.
3. A diagram of Earth's greenhouse (possibly
a simple picture of Earth, sun, light from
the sun, and the atmosphere as a
greenhouse cover) with clouds, ice/snow/
deserts, and oceans included. Students
develop their own, based on discussion—
not just a copy.
Extensions:
The bottles lend themselves to several
possibilities and students should be
encouraged to design their own experiments.
1. Students may put plants in the bottles and
test the effect of plant cover on the
greenhouse temperatures.
2. Students may test the effect of wet versus
dry soil on greenhouse warming.
3. Students can try different colors or types of
lights Qights filtered with colored
cellophane, fluorescent vs. incandescent
bulbs, etc.) to see which contribute most to
warming.Q
GREENHOUSE EFFECT UNIT
50
-------
What Factors Influence a Greenhouse?
SruDENiGuiDE—ACTIVITY 7
Definitions of Terms:
Albedo: The percentage of solar energy reflected back by a surface.
In the atmosphere, clouds reflect solar energy into space as visible
light. At the Earth's surface, light-colored land (i.e., deserts, snow
and ice fields) and sea surfaces also reflect solar energy back into
space.
Feedback: A process in which part of the output of a system is fed
back to another pan of the system. Feedback generally serves as an
internal control on what goes on in a system. Positive feedback can
encourage more of what is already happening; negative feedback
will discourage what is happening. In the case of global climate
change, positive feedback would act to increase global warming
while negative feedbacks would act to reduce it.
Activity:
You will set up a selection of model
greenhouses with different properties and will
observe, record, and graph the differences in
temperature between them. Be prepared to
discuss the possible reasons for the observed
differences.
Materials:
For each team of four students:
• Four soda bottle "experimental chambers"
(see page 43)
• Four thermometers
• 3 Cups of soil (garden soil or potting
soil)
• 1.5 Cups of white sand or perlite
• One 150-watt flood light bulb
• Clamp-on, portable reflector lamp
• Stand to support lamp setup
• Graph paper
Procedure:
1. Label your bottles A, B, C, and D, with
bottle B having the white paint and bottle
D having the sealed base to hold water.
2. Fill the base of bottles A and B with soil,
bottle C with white sand, and bottle D with
room-temperature water. Your greenhouses
are now ready (Figure 1).
3. Tape a thermometer (using cellophane tape
or light-colored masking tape, not black
electrical tape) to the sides of each bottle
(facing out). Make sure the bulb of the
thermometer is just above the top of the
opaque base (if the bulb is below the base,
the thermometer may record the heat
absorbed directly by the soil or water, and
GREENHOUSE EFFECT UNIT
51
-------
StuDENiGuiDE—ACTIVITY 7
complicate the results). Cap the bottles.
Important: The thermometers should all
read the same temperature before
beginning the experiment. If not, you can
"zero" them by recording the difference
and adjusting for the difference when the
observations are made. For example, if
thermometer A reads 22 °C and
thermometer B reads 23 °C when they both
should read the same, you can either add
1 °C to every reading of A or subtract 1 °C
from every reading of B to correct for the
difference.
4. Set up a graph of time (in minutes) versus
temperature upon which to record your
observations. The temperature axis
should be approximately 20 °C to
B
Paint upper
1/3 white
40 °C. Which bottle do you think will get
the hottest? Coolest? Why? Record your
prediction in your logbook.
5. Each person in your team should have a
specific responsibility during the
experiment (either by keeping track of the
time or recording the temperature for the
different bottles every two minutes).
6. Place the bottles approximately 6" away
from the lamp with the thermometers
facing away from the light.
7. Turn on the light and begin collecting your
data. Continue the experiment for at least
20 minutes.
8. Compare the graphed information from the
different bottles. Discuss the results and
develop some possible explanations-^)
D
Dark soil in base A and B White sand Room temperature
in base H2O in base
Figure 1. Experimental Chambers Simulating Different Factors That Influence Climate
GREENHOUSE EFFECT UNIT
52
-------
What Makes the Earth
Like a Greenhouse?
ACTIVITY 8
Lesson Focus:
What are the atmospheric differences between Earth and other
planets in the solar system?
Objective:
The student will be able to:
1. Compare the Earth's atmosphere with the atmospheres of
other planets.
2. Build a model of the Earth's atmospheric composition.
Time:
1 class period
Grade Level:
8-10
Key Concepts:
Greenhouse gases, atmospheric chemistry, modeling
Definition of Terms:
Goldilocks Principle: The planets Earth, Mars,
and Venus are very different from one another
in terms of temperature, atmospheric
chemistry, and atmospheric pressure. Planetary
climatologists have noted that Venus is too hot,
Mars is too cold, but the Earth is just right to
support life. This is referred to as the
Goldilocks Principle.
Greenhouse Gases: (also called trace gases)
Gases in Earth's atmosphere that make up a
very small part of the total atmospheric
composition. Important greenhouse gases
include water vapor, carbon dioxide (CO2),
methane (CH4), chlorofluorocarbons (CFCs),
and ozone (O3).
Visible Light: Light in the area of the
electromagnetic spectrum that can be seen
with human eyes, generally extending from
violet light (shorter wavelengths) to red light
Conger wavelengths).
Infrared Radiation: Although it can not be
seen by the human eye, most objects absorb
and emit infrared radiation. The infrared
portion of the electromagnetic spectrum has
longer wavelengths than visible light. It is also
known as heat radiation.
GREENHOUSE EFFECT UNIT
-------
ACTIVITY 8
Background:
The greenhouse effect is a well-established
theory in the atmospheric sciences. The
explanation for the greenhouse effect is that
certain trace atmospheric gases appear
transparent to incoming visible (short-wave)
light but act as a barrier to outgoing infrared
(long-wave) radiation. These trace gases are
often referred to as "greenhouse gases"
because they function much like the glass
plates found on a greenhouse used for growing
plants. (Note to Teacher: if you have done
Activity 6 or 7, suggest to your students that
although Earth's "greenhouse cover" is not as
obvious as that of the plastic bottle, the effect
is the same. Earth's atmosphere acts like our
"bottle"). The atmosphere is composed of
gases (e.g., H2O, CO2) of just the right types,
and in just the right amounts, to warm the
Earth to temperatures suitable for life. The
effect of the atmosphere to trap heat is the true
"Greenhouse Effect".
The physical evidence for the effect of
greenhouse gases can be evaluated by
comparing the Earth with its nearest planetary
neighbors, Venus and Mars (Table 1). These
planets have either too much greenhouse
effect, or too little to be able to sustain life as
we know it. The differences between the three
planets has been termed the "Goldilocks
Principle" (Venus is too hot, Mars is too cold,
but Earth is just right).
Mars and Venus have essentially the same
types and percentages of gases in their
atmospheres (Table 2). However, they have
very different atmospheric densities. Venus has
an extremely dense atmosphere, so the
concentration of C02 is responsible for a
"runaway" greenhouse effect and very high
surface temperatures. Mars has almost no
atmosphere; therefore, the amount of CO2 is
not sufficient to supply a warming effect and
the surface temperatures of Mars are very low
as a result (Table 1).
Earth has a vastly different type of atmosphere.
The percentage of CO2 in the Earth's
atmosphere is much less than that found on
Venus or Mars. Earth's atmospheric pressure is
between that found on Venus or Mars. Many
scientists believe the composition of our
atmosphere is due to the presence of life. Life
acts to keep Earth's atmosphere in a dynamic
balance with a gaseous composition that is
chemically unstable. In other words, if life
were to completely disappear from Earth,
eventually, Earth's atmospheric composition
could come to closely resemble either Mars or
Venus. Only with life continually producing
oxygen (through photosynthesis), and
removing and recirculating CO2, does Earth's
atmosphere stay fairly stable.
Activity:
In this activity, students will learn of the
differences between the atmospheres of the
planets in our solar system. They will also
construct models of the Earth's atmosphere
and those of other planets in order to
understand the relationships among the
different atmospheric gases.
Materials:
• Colored cotton balls, jellybeans, colored
paper (or similar materials) to represent
gases in the atmosphere
• Resealable plastic bags
GREENHOUSE EFFECT UNIT
54
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ACTIVITY 8
Table 1:
The atmospheric factors responsible for the some influence on planetary temperature, but
planetary differences are provided in the table the greenhouse gases and atmospheric density
below. The relative distance from the sun has have more of an impact on temperature.
Surface Pressure
Major Greenhouse Gases (GHG)
Temperature if no GHG (°C)
Actual Temperature (°C)
Temperature Change due to GHG
Venus
90
C02
-46
477
+523
Earth
1
H20, C02
-18
15
+33
Mars
0.007
C02
-57
-47
+10
Table 2:
The chemical composition of the atmospheres
are important as well (at least to the presence
of life). The major gases and their percentages
are listed below.
Gas
Carbon Dioxide (CO2)
Nitrogen (N2)
Oxygen (O2)
Argon (Ar)
Methane (CH4)
Venus
96.5%
3.5%
Trace
0.007%
0
Earth
0.03%
79%
21%
1%
0.002%
Mars
95%
2.7%
0.13%
1.6%
0
GREENHOUSE EFFECT UNIT
55
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ACTIVITY 8
Procedure:
1. Discuss the "Goldilocks Principle". Use the
information in Tables 1 and 2 to engage the
class in a discussion of the Greenhouse
Effect. If available, you may want to share
illustrations or slides of Mars, Venus, and
Earth.
2. After discussing the atmospheres of Earth
and the other planets, ask the students (in
teams or pairs) to build models of the
atmospheres of Earth and the other planets.
3. Depending on the material available, ask
students to represent the atmospheric gases
with different colored paper, string, cotton
balls or jelly beans (we will use jellybeans
for examples in this activity). They might
represent nitrogen (N2) with yellow jelly
beans, oxygen (O2) with blue, and carbon
dioxide (CO2) with black. Representing
atmospheric density with jellybeans is
impractical - if Earth's atmosphere has 100
jellybeans, Venus will have 9,000, and
Mars will have slightly more than 1/2 a
jellybean (0.6). Suggest that the students
use 10 or 100 as the base number for each
planet. Let the students know what the real
differences in density are.
4. Challenge the students to produce a model
atmosphere for each planet by placing the
appropriate number of jellybeans in three,
small, resealable plastic bags. The
necessary information is provided in Table
2. They will have to translate percentages
into numbers of jellybeans, and in many
cases, will face the difficulty of cutting the
jellybeans into small enough pieces to
represent small atmospheric
concentrations.
5. Have the students display their work in the
classroom and allow time for them to
observe and discuss each others work.
6. Discuss the students's models with the
class. Ask questions of students regarding
why they think Earth's atmosphere is
suitable for life while the other planets'
atmospheres are not.
Student Learning Portfolio:
1. Models of planetary atmospheric
compositions.
2. A journal entry to explain what they have
learned about the Earth's atmosphere as
compared to the other planets.Q
GREENHOUSE EFFECT UNIT
56
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What Makes the Earth
Like a Greenhouse?
STUDENTGUIDE—ACTIVITY 8
Definition of Terms:
Goldilocks Principle: The planets Earth, Mars, and Venus are very
different from one another in terms of temperature, atmospheric
chemistry, and atmospheric pressure. Planetary climatologisis have
noted that Venus is too hot, Mars is too cold, but the Earth is just
right to support life. This is referred to as the Goldilocks Principle.
Greenhouse Gases: (also called trace gases) Gases in Earth's
atmosphere that make up a very small part of the total atmospheric
composition. Important greenhouse gases include water vapor,
carbon dioxide (CO2), methane (CH4), chloroflourocarbons (CFCs),
and ozone (O3).
Visible Light: Light in the area of the electromagnetic spectrum that
can be seen with human eyes, generally extending from violet light
(shorter wavelengths) to red light (longer wavelengths).
Infrared Radiation: Although it can not be seen by the human eye,
most objects absorb and emit infrared radiation. The infrared portion
of the electromagnetic spectrum has longer wavelengths than visible
light. It is also known as heat radiation.
Activity:
You will learn of the differences between the
atmospheres of the planets in our solar system.
You will construct models of the Earth's
atmosphere and those of other planets in order
to understand the relationships among the
different atmospheric gases.
Materials:
• Colored cotton balls, colored paper, colored
jellybeans (or similar materials to represent
gases in the atmosphere.
• Resealable plastic bags
GREENHOUSE EFFECT UNIT
Procedure:
1. With your partner or team, identify the
different gases to be included in a model of
the atmospheres of Earth, Mars, and Venus
(see Table 1, page 58).
2. Depending on the material available,
represent the atmospheric gases with
different colored paper, string, cotton balls
or jelly beans (we will use jellybeans for
examples in this activity). You could
represent nitrogen (N2) with yellow jelly
57
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STUDENTGUIDE—ACTIVITY 8
beans, oxygen (02) with blue, and carbon
dioxide (C02) with black.
3. Determine the practicality of representing
atmospheric density with jellybeans. If
Earth's atmosphere has 100 jellybeans how
many would you need to represent Venus
or Mars?
Table 1:
The chemical composition of the atmospheres
are important as well (at least to the presence
4. For each planet, place the appropriate
number of jellybeans in a small, resealable
plastic bag. To do this, you will have to
translate percentages (from Table 1) into
numbers of jellybeans. How do the
different "planets" compare?
5. Why do you think Earth's atmosphere is
suitable for life while Venus and Mars have
no apparent life?Q
of life). The major gases and their percentages
are b'sted below.
Gas
Carbon Dioxide (CO2)
Nitrogen (N2)
Oxygen (O2)
Argon (Ar)
Methane (CH4)
Venus
96.5%
3.5%
Trace
0.007%
0
Earth
0.03%
79%
21%
1%
0.002%
Mars
95%
2.7%
0.13%
1.6%
0
Notes:
GREENHOUSE EFFECT UNIT
58
-------
What Is the Carbon Cycle?
ACTIVITY 9
Lesson Focus:
Objective:
The student will be able to:
1. Describe a simple carbon cycle by drawing the key components
of the cycle and constructing a collage.
2. Identify carbon sources, sinks, and release agents.
3. Speculate on the connection between the carbon cycle and
carbon's role in the Greenhouse Effect
Time:
2-3 Class Periods
Grade Level:
8-10
Key Concepts:
Carbon cycle, carbon sinks, climate change
Definition of Terms:
Carbon: An important element that forms the
structure of all life on Earth.
Carbon Dioxide (CO2): The primary form of
carbon in Earth's atmosphere.
Carbon Cycle: The cycle of carbon (in solid
and gaseous forms) through living organisms
(biological) and nonliving forms
(geochemical).
Carbon Sinks (also called reservoirs):
Locations in the biosphere where excess
carbon is stored (e.g., long-lived trees,
limestone, fossil fuels).
Release Agents: Events that cause the carbon
atom to be released from its sink and reentered
into the cycle (e.g., volcanic activity, forest
fires).
Background:
All living organisms are based on the carbon
atom. Unique among the common elements of
the Earth's surface, carbon atoms have the
ability to form bonds with as many as four
other atoms, including other carbon atoms, and
to form double bonds to itself. These attributes
make possible the existence of all the organic
compounds that are essential to life on Earth.
Carbon, in the form of carbon dioxide, is also
an important part of our atmosphere, and
carbon-containing rocks (such as limestones)
are an important part of Earth's crust
CARBON CYCLE UNIT
69
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ACTIVITY 9
Carbon atoms are continually moving through
living organisms, the oceans, the atmosphere,
and the crust of the planet. This movement is
known as the carbon cycle. The paths taken by
carbon atoms through this cycle are extremely
complex, and may take literally millions of
years to come full circle. Consider, for
example, the journey of a "typical" carbon
atom that existed in the atmosphere as part of a
carbon dioxide molecule some 360 million
years ago, during the Carboniferous Period.
That CO2 molecule drifted into the leaf of a
large fem growing in the extensive tropical
swamp forests of that time. Through the
process of photosynthesis, the carbon atom
was removed from the CO2 molecule, the
oxygen was released back into the air, and the
carbon was used to build a molecule of sugar.
The sugar might have been broken down by
the plant at a later time, to release the energy
stored inside, but this molecule was
transformed instead into a long-lived structural
part of one of the plant cells. Soon after, the
fem died, and the remains sank into the muck
at the bottom of the swamp. Over thousands of
years more plants grew in the swamp and their
remains also sank into the swamp, forming a
layer of dead plant material many meters thick.
Gradually, the climate changed, becoming
drier and less tropical. Sand, dust, and other
materials slowly covered the ancient swamp
and sealed the decaying vegetation under an
ever-thickening layer of sediment. The
sediment hardened, turning to sedimentary
rock. The carbon atom stayed trapped in the
remains of the long-vanished swamp while the
pressure of the layers above slowly turned the
material into coal. Some 360 millions of years
later, the coal bed was mined by humans and
burned to fuel industrial civilization. The
process of burning released the energy stored
in the carbon compounds in the coal, and
reunited the carbon atom with oxygen to form
CO2 again. The CO2 was released to the
atmosphere through the smokestack and the
journey continues. Many other paths are
possible, some taking only hours or days to
trace, some, like the one above, many millions
of years.
The aggregation of the possible paths of
carbon, where they may be stored for extended
periods (the "sinks"), where they are likely to
be released back to the atmosphere (the
"source"), and what triggers those sources (the
"release agents"), together defines the carbon
cycle. Carbon sinks may include such things
as long-lived trees, limestone (formed from the
carbon-containing shells of small sea creatures
that settle to the ocean bottoms and build up
into thick deposits), plastic (a modem
invention, but very long-lived), and burial of
organic matter (such as formed fossil fuels).
Carbon sources include the burning of fossil
fuels and other organic matter, the weathering
of limestone rocks (which releases C02), and
respiration of living organisms. Release agents
include volcanic activity, forest fires, and
many human activities.
Activity:
Students will make carbon cycle drawings and
collages.
Materials:
• Magazines and newspapers
• Tagboard for collages
• Worksheets (provided)
CARBON CYCLE UNIT
60
-------
ACTIVITY 9
Procedure:
1. Distribute worksheets to students. Using
class discussion, brainstorrning, or question
and answer methods, discuss the simplified
carbon cycle. Students should draw their
own carbon cycle.
2. Have students look up carbon and its cycle
in a science text, chemistry text, or
encyclopedia. Through class discussion,
students can share what they have
discovered.
3. Discuss a much more complicated carbon
cycle with sinks and release agents.
4. Using magazines and newspapers assign
the students (working in small groups) the
task of developing a collage illustrating the
carbon cycle. Display the collages in your
classroom.
Student Learning Portfolio:
1. Student worksheets
2. Written answers in the student notebook to
the following questions:
a. What gas do humans and animals
exhale?
b. Write the formula for this exhaled gas.
c. List some "sinks" and "release" areas
for this fundamental element
d. Does the carbon cycle help explain
global climate changes?
3. A collage illustrating the carbon cycle.
Extensions:
Students may be encouraged to write a story
about a carbon atom as it moves through its
cycle with illustrations of the carbon taking on
all its many forms.Q
Notes:
CARBON CYCLE UNIT
61
-------
ACTIVITY 9
Notes:
CARBON CYCLE UNIT 62
A
-------
What Is the Carbon Cycle?
SruDENTGuiDE—ACTIVITY 9
Definition of Terms:
Carbon: An important element that forms the structure of all life on
Earth.
Carbon Dioxide (CO2): The primary form of carbon in Earth's
atmosphere.
Carbon Cycle: The cycle of carbon (in solid and gaseous forms)
through living organisms (biological) and nonliving forms
(geochemical).
Carbon Sinks (also called reservoirs): Locations in the biosphere
where excess carbon is stored (e.g., long-lived trees, limestone, fossil
fuels).
Release Agents: Events that cause the carbon atom to be released
from its sink and reentered into the cycle (e.g., volcanic activity,
forest fires).
Activity:
You will make a chart of the carbon cycle and
a collage for your classroom.
Materials:
• Magazines and newspapers
• Tagboard for collages
• Worksheets
Procedure:
1. With your class, discuss the carbon cycle.
Draw a simplified carbon cycle on your
worksheet or in your journal.
2. Look up carbon and its cycle in a science
text, chemistry text, or encyclopedia. Share
your findings with the class.
3. With your class, consider a more
complicated carbon cycle including sinks
and release agents.
4. Look through magazines or newspapers for
illustrations that could be part of the carbon
cycle (for example, plants, animals,
automobile exhaust, fires, volcanoes).
Develop a collage illustrating the carbon
cycle and display the collage in your
classroom.Q
CARBON CYCLE UNIT
63
-------
SiuDENTGuiDE—ACTIVITY 9
The Carbon Cycle and Climate Change
Some Carbon Facts:
A Simple Carbon Cycle:
Carbon Sinks:
Carbon Release Agents:
CARBON CYCLE UNIT
64
-------
Where Does CO2 Come From?"
ACTIVITY 10
Lesson Focus:
What are the sources of CO2?
Objective:
The student will be able to:
1. Identify sources of CO2.
2. Discuss the use of "control" and "treatment" in experimental
studies.
3. Explain the use of a chemical indicator in experimental studies.
4. Formulate conclusions based on observed and recorded data on
sources of CO2.
Time:
2 Class Periods
Grade Level:
8-10
Key Concepts:
Carbon sources, scientific inquiry, experimentation
* Adapted with permission from curriculum materials developed by the U.S.
Department of Energy, Lav/rence Livermore National Laboratory, Livermore,
California.
Definition of Terms:
Controlled Experiment: An experiment that is
based on a comparison of a control group and
a treatment group. The control and treatment
groups are similar in every way except for the
treatment used in the experiment
Control Group: The group that is not
subjected to any experimental changes or
manipulations. It is used as a basis for
comparison.
CARBON CYCLE UNIT
Treatment Group: The group that is treated or
manipulated according to design of die
experiment The treatment group is also
known as the experimental group.
Indicator: A substance used to visually detect
the presence of a particular material or
compound
Carbon Cycle: The cycle of carbon (in solid
and gaseous forms) through living organisms
(biological) and nonliving forms
(geochemical).
65
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ACTIVITY 10
Carbon Source: Anything that releases CO,
(living, dead, nonliving) into the atmosphere is
considered to be a carbon source.
Carbon Sinks (also called reservoirs):
Locations in the biosphere where excess
carbon is stored (e.g. long-lived trees,
limestone, fossil fuels).
Background:
Carbon dioxide (CO2) is the most important of
the "greenhouse" gases - those gases that act
to trap solar energy in the form of heat
Although there are other important greenhouse
gases, including methane (CH4), nitrous oxide
(N2O), and chlorofluorcarbons (CFCs), it was
CO2 that scientists first observed increasing in
the atmosphere. Many scientists believe that
CO2 will be responsible for most of the
increases in Earth's temperature. Carbon
dioxide concentrations in the atmosphere are
presently at approximately 350 pans per
million (ppm), and increasing at an average
rate of 0.5% per year. If the trend continues,
CO2 concentrations will reach 600 ppm or
more during the next century.
Anything that releases CO2 (living, dead,
nonliving) into the atmosphere is considered to
be a source. Anything that absorbs and holds
CO2 from the air or water is considered a sink
(because, like a sink in your home, it acts as a
"holding reservoir"). The continued build-up
of CO2 in the atmosphere is strong evidence
that there are currently more sources of CO2
than sinks. What are the sources for the extra
CO2? Human activities are thought to be
primarily responsible for the observed
increases. Of the anthropogenic (humans are
the origin) sources of CO2, fossil fiiel
combustion accounts for 65%, deforestation
(CO2 that is released from trees that are cut and
burned, or left to decay) accounts for 33%, and
the by-products of cement production accounts
for the remaining 2%. There are natural
sources of CO2 as well. As the students will
observe, plants and animals give offCO2.
Carbonate rocks contain CO2 that can be
released by exposure to acid and/or
weathering. Certain naturally carbonated
spring waters (e.g., Perrier water) contain CO2
because the water has passed through
carbonate rock on its way to the surface.
Volcanoes are also a source of CO2. However,
these geological sources are insignificant
compared to human sources. It is estimated
that it would require some 900 volcanic
eruptions of the size of El Chicon (Mexico,
1988) every year to equal annual industrial
CO2 emissions
Plants (both terrestrial plants and marine
plankton) are the most important carbon sinks,
taking up vast quantities of CO2 through the
process of photosynthesis. To a lesser extent,
atmospheric CO2 can also be dissolved directly
into ocean waters and thereby be removed
from the atmosphere. As this exercise will
illustrate, plants also release CO2 through the
process of respiration, but on a global, annual
basis, the amount of CO2 taken up by plants
through photosynthesis, and released through
respiration approximately balance out Thus,
the CO2 released from human activities is truly
"extra" CO2 and may continue to build up in
the atmosphere, unless plants begin to increase
their photosynthetic rate to utilize the extra
CO2, and/or the amount of CO2 dissolved in
the ocean water increases.
Carbon dioxide has the property of forming a
weak acid (carbonic acid) when dissolved in
CARBON CYCLE UNIT
66
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ACTIVITY 10
water. Chemists have taken advantage of this
fact to develop a simple test for the presence of
C02 in gaseous samples. The chemical
bromothymol blue (BTB) is a sensitive
indicator of the presence of acid. When gas
containing CO2 is bubbled through a BTB
solution, carbonic acid is formed, and the acid
turns the solution from dark blue to green,
yellow, or very pale yellow, depending on the
CO2 concentration (lighter colors mean higher
concentrations). Students will use this reaction
to study some sources of CO2, beginning first
with a qualitative illustration of the change in
BTB color with pure C02 (from baking soda
and vinegar), and proceeding to an exploration
of some natural and anthropogenic sources of
C02.
Activity:
Students will predict, observe, record, and
make conclusions about sources of CO2. They
will use a color indicator of CO2,
bromothymol blue (BTB) to detect the
presence and relative amount of CO2 in
gaseous samples.
Materials:
For the class:
• Three to four bottles of BTB working
solution (naxing instructions below)
• Vinegar
• Baking soda
• Foil
For each team of students:
• Test tube rack
• Four test tubes
• A hole stopper with tubing attached
• Straw
• Cotton balls
• One sprig of Elodea (available in pet stores)
• Balloon
• Hand pump
• Roll of masking tape, or circle of similar
diameter as a balloon circumference
measuring device.
• Student lab notes (provided)
• Safety glasses
Safety Precautions:
As with any laboratory activity, safety
precautions are critical. All chemicals should
be treated as though they are potentially
dangerous. Students should be warned not to
ingest the BTB. They should take care to avoid
prolonged contact with the chemical. In any
laboratory activity involving the use of
chemicals, safety glasses should be worn. It is
important to instill respect for laboratory
procedures.
Procedure:
Preparation of the BTB solution: Measure
0.5 grams of the dry BTB powder into 500 ml
of tap water. This will provide a 0.1 % stock
solution. To prepare the working solution, mix
1 part staf.V soh'Tion with 20 parts tap water.
For classroom use, 1 liter of working solution
should serve iO laboratory teams. To make it
faster for the student k oms to decant what they
need, you may wish to separate the working
solution into three or four smaller bottles.
Prior to conducting the following experiments,
students should have a working knowledge of
die carbon cycle and the importance of CO2 in
global climate change. Much of this
information is covered in Activity 9 (What is
the Carbon Cycle?).
CARBON CYCLE UNIT
67
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ACTIVITY 10
A. Detecting CO2 Gas
The students will conduct an experiment
designed to detect the presence of C02.
When combined, baking soda and vinegar
produce pure CO2. In this experiment, the
BTB will dramatically change color (from
bright blue to yellow) when introduced to
the CO2. This basic experiment will form
the basis of the experiments to follow.
Detailed procedural instructions are
included in the student guide.
Discussion points: Discuss the usefulness
of an indicator like BTB for scientific
experimentation. Discuss the need for the
control tube A.
B. Are animals a source ofCO2?
The students will conduct an experiment
designed to determine if animals are a
source of CO2. The "animals" used in this
experiment are themselves as they
determine if CO2 is present in the breath
they exhale. In order to be certain that
every team uses the same amount of
breath, they will store their breath in a
balloon which will be held at a standard
size of 7.5 cm. in diameter. Your students
*v; aware that human breath is
ristic cf animal 'ucaih in general. It
is important to note that the air we breathe
in contains approximately 350 ppm CO2,
whereas the air we exhale contains
approximately 10,000 ppm CO2. The extra
CO2 is a waste product of our respiration
(conversion of food to energy).
Detailed procedural instructions are
included in the student guide
Discussion points: Why is it important for
everyone to use the same amount of
breath? (This is a controlled experiment.)
Are there differences in the concentrations
of C02 in human breath and the ambient
air? (Human breath is much more
concentrated.) How can you tell? (The
indicator should be much lighter in color
for human breath.)
C. Are plants a source ofCO2?
Plants, just like animals, respire. When
they do respire, they give off CO2 just like
animals do. Unlike animals, however,
plants can also act as a carbon sink when
they take in CO2 through the process of
photosynthesis. The balance between CO2
taken in by photosynthesis and that
released through respiration determines
whether plants act as net sinks or sources of
CO2. In this experiment the water plant
Elodea will be used to examine how plants
release CO2.
Detailed procedural instructions are
included in the student guide.
Discussion points. Why was the light
excluded? (Light was excluded to keep the
plant from photosynthesizing.) Why was
there a second rube without Elodea1? (The
second rube serves as a control.)
D. Comparing the Results
Ask students to compare the color
differences between the tubes used in the
various activities (tube A - control, tube D
- animal breath, tube F - plant respiration).
Of the three rubes being compared, which
is the lightest in color? Why is that?
Discuss the design of the experiments with
emphasis on the need for control and
treatment groups.
CARBON CYCLE UNIT
68
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ACTIVITY 10
Student Learning Portfolio:
Student data sheets mounted in log books.
Extensions:
1. Using BTB, students could bring in other
possible sources to test (some examples
include limestone, chalk, carbonated
beverages).
2. What happens to the BTB color if the
Elodea is placed in the light after
incubating in the solution in the dark
overnight? How quickly do the changes
occur (This activity provides an excellent
representation of the balance between
photosynthesis and respiration).
3. Teacher Demonstration. Are fossil fuels a
source ofCO2l This experiment will test
for the presence of CO2 in automobile
exhaust. You will need to fill a balloon full
of car exhaust before the demonstration. To
do so, have an assistant hold a large metal
funnel (10-15 cm diameter) over the end of
a car exhaust pipe, with the small end
facing out and a balloon over that end
(Example A). Handle the funnel with pot
holder gloves as it can become hot. Hold
the funnel tightly to the exhaust pipe and
the balloon should inflate immediately
(Example B). Gently pressing on the
accelerator may expedite the process.
Over-inflate past the 7.5 cm diameter size.
Twist the stem of the balloon several times
to close it, then roll the stem inward and
clamp it with a paper clip or binder clip
(Example C).
a. Use two clean test tubes 1/4 full of BTB
Gabel "treatment" and "control").
b. Carefully let enough exhaust escape
from the balloon to reduce it to 7.5 cm
(use the template from exercise B).
CARBON CYCLE UNIT
c. As in Exercise B, insert the straw into
the balloon and gentfy bubble the
exhaust through the solution in the
treatment tube.
d. Ask students to record the color
differences between the control and
treatment tubes in their lab notes.
Exhaust is the waste product of the
burning of fossil fuel, and is extremely
rich in CO2.
Warning! For safety reasons, we recommend
that this extension be carried out only as a
teacher demonstration. Automobile exhaust
contains carbon monoxide, which is an
odorless, moderately toxic, poisonous, and
flammable gas. Carbon monoxide, may cause
headache, dizziness, low blood pressure,
damage to blood cells, and asphyxiation.
Example A. Mcud funncl
C
J
Exhaust pipe
Hold funnel tightly
to pipe using heat-
resistant gloves
Example B.
Balloon
Funnel
Exhaust pipe
Example C.
Balloon neck rolled
and sealed with
• paper clip
-------
ACTIVITY 10
Avoid breathing gas. Avoid contact with eyes, away from all ignition sources. Balloons
skin, and clothing. Wash thoroughly after should be labeled as flammable and poisonous
handling. Use only with adequate ventilation gas and stored in an exhaust hood.Q
in an exhaust hood. May cause flash fire. Keep
Notes:
CARBON CYCLE UNIT 70
-------
Where Does CO2 Come From?*
SiuDENTGuiDE—ACTIVITY 10
Definition of Terms:
Controlled Experiment: An experiment that is based on a
comparison of a control group and a treatment group. The control
and treatment groups are similar in every way except for the
treatment used in the experiment
Control Group: The group that is not objected to any experimental
changes or manipulations. It is used as a basis for comparison.
Treatment Group: The group that is treated or manipulated
according to design of the experiment. The treatment group is also
known as the experimental group.
Indicator: A substance used to visually detect the presence of a
particular material or compound.
Carbon Cycle: The cycle of carbon (in solid and gaseous forms)
through living organisms (biological) and nonliving forms
(geochemical).
Carbon Source: Anything that releases CO2 (living, dead,
nonliving) into the atmosphere is considered to be a carbon source.
Carbon Sinks (also called reservoirs): Locations in the biosphere
where excess carbon is stored (e.g., long-lived trees, limestone, fossil
fuels).
* Adapted with permission from curriculum materials developed by the U.S.
Department of Energy, Uwience Uvrrnxxe Nauonal Laboi^ory, Uvermore,
California.
Activity:
You will predict, observe, record, and make
conclusions about sources of CO2 using a
color indicator of COr bromothymol blue
(BIB) to detect the presence and relative
amount of CO2 in gaseous samples.
Materials:
You and your partners will need the following:
• BTB working solution
• Vinegar
• Baking soda
• Small piece of foil
CARBON CYCLE UNIT
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SiuDENTGuiDE—ACTIVITY 10
• Test tube rack
• Four test tubes
• A hole stopper with tubing attached
• Straw
• Cotton balls
• One sprig of Elodea
• Balloon
• Hand pump
• Roll of masking tape, or circle of similar
diameter as a balloon circumference
measuring device
treatment Place both tubes in the rack.
What might happen to the BTB in tube
B that is exposed to C02 from a baking
soda/vinegar mix and what will happen
to the BTB in Tube A that is left alone?
Record your predictions on your lab
notes.
3. Make a small "boat" for the baking
soda by wrapping the foil square around
the tip of a pencil to form a cone
(Figure 1). Fill the foil cone 1/2 full of
baking soda.
Figure 1.
Procedure:
A. Detecting CO2 gas
You are going to conduct an experiment
designed to detect the presence of CO2.
When combined, baking soda and vinegar
produce pure CO2. In this experiment, the
BTB will dramatically change color (from
bright blue to yellow) when introduced to
the CO2. This basic experiment will form
the basis of the experiments to follow.
1. For the first experiment, each team will
need one test-tube rack, three test tubes,
a one-hole stopper with tubing attached, Rgure 2.
two cotton balls, a 1-inch square of
aluminum foil, vinegar, baking soda,
and the BTB solution.
2. Two of the test tubes should be labeled
"A" and "B"; the other should be left
unlabeled. Fill tubes A and B
approximately 1/4 full with the BTB
solution. The unlabeled tube should be
filled approximately 1/4 full of vinegar.
Record the color of the BTB in tubes A
and B on their lab note sheets. Tube A
will be the control; tube B will be the
baking soda
(1/2 full)
aluminum foil
4. Carefully slide the foil container inside
the unlabeled vinegar test tube. The foil
cone should float upright. It is useful to
tilt the tube at an angle to accomplish
this. Plug the tube with the stopper and
tubing (Figure 2).
CARBON CYCLE UNIT
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SiuDENiGuiDE—ACTIVITY 10
5. Place the free end of the tubing in tube B
making sure the end of the tubing reaches
the oottom of the tube
(Figure 3). Place a
cotton ball into the
neck of tube B.
Figure 3.
6. Mix the vinegar and soda together by
gently swirling the tube from side-to-
side. Don V shake up and down! Gas
bubbles will begin to bubble rapidly out
of the tubing into the BTB solution in
tubeB.
7. After 1 or 2 minutes, note the color in
tubes A and B and record this on your
lab note sheets.
8. Why might an indicator like BTB be
useful in scientific experimentation?
What was the role of tube A in this
experiment?
B. Are animals a source ofCO2?
You will conduct an experiment designed
to determine if animals are a source of
GO2. Remember, you are an animal and in
this experiment, you will determine if CO2
is present in the breath you exhale.
1. For this experiment each team will need
a test-tube rack, two test tubes, a straw,
a cotton ball, a balloon, BTB solution,
and a template approximately 7.5 cm in
diameter.
2. Fill two clean test tubes 1/4 full of the
BTB solution and label them "C" and
"D". Record ihe color in your lab notes.
3. You are going to test for the presence of
CO2 in your breath. You will store your
breath in a balloon that will be held at a
standard size of 7.5 cm. in diameter. To
control the size, blow the balloon up
while it is inserted in the 7.5 cm
template cutout and stop when the
balloon touches the sides of the hole
(Figure 4). Twist and pinch the neck of
the balloon to prevent air from
escaping, but don't tie it
4. While still preventing the air from
escaping, insert a straw into the neck of
the balloon up to the twisted portion.
Have one team member seal the
opening of the balloon around the straw
by pulling the neck of the balloon
tightly to one side and pinching it off
with their fingers. You may need to
practice this a few times.
5. Predict what will happen to the color
when you bubble your breath through
the solution in tube D. Record your
prediction in your lab notes.
6. Insert the straw into the BTB solution in
tube D. Insert a cotton ball into the top
of the test tube to help hold the straw
steady. Gently release air from the
balloon by slowly untwisting the neck.
If the air is let out too fast, the solution
will bubble up and out of the tube.
Allow the air to bubble out at a steady
rate until the balloon is empty. Observe
CARBON CYCLE UNIT
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SiuoENTGuiDE—ACTIVITY 10
the color of the solution, compare the
color with tube C, and record your
observations in your lab notes.
7. Tape the tube shut and set aside for later
use.
C. Are plan:s a source ofCO2?
In this experiment the water plant Elodea
will be used to examine how plants release
C02.
1. For this experiment, each team will
need a test tube rack, two test tubes,
enough foil to cover both tubes, a 3-cm
sprig of Elodea, and BTB solution.
2. Label the two test tubes as "E" and "F'.
Fill each tube 1/3 full of BTB solution.
Record the color of the solution in your
lab notes.
Cardboard template
3. Place the sprig of Elodea into tube F.
Use a pencil or pen to push it all the
way into the bottom of the tube.
4. Wrap both tubes in foil so that no light
can get in. Place them in the rack. They
will be left overnight Predict any color
change that you think might occur in
the tubes. Record this prediction in your
lab notes.
5. Uncover the test tubes and observe the
color of the solution. To get a better
comparison, remove the Elodea and
hold both tubes up to a white sheet of
paper. Record the color difference on
the data sheet. Tape tube F shut and set
it aside for later use.Q
Balloon
B
Figure 4.
Insert straw.
twist, pinch
balloon njck
to seal
BTB
CARBON CYCLE UNIT
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STUDENTGUIDE—ACTIVITY 10
Lab Notes:
Activity A
l\ibeA
l\ibeB
What color..; the
BTB before the experiment?
Predicted results:
Observed results:
What happened and why?
Activity B
TbbeC
l\ibeD
What color is the
BTB before the experiment?
Predicted results:
Observed results:
What happened and why?
CARBON CYCLE UNIT
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STUDENTGUIDE—ACTIVITY 10
Activity C
TtabeE
IbbeF
What color is the
BTB before the experiment?
Predicted results:
Observed results:
What happened and why?
Notes:
CARBON CYCLE UNIT
76
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How Do Scientists Analyze
Greenhouse Gases and Global
Temperature Data Over Time?
ACTIVITY 11
Lesson Focus:
What do scientists do with research data they collect?
Objective:
The student will be able to:
1. Comprehend how scientists gather data.
2. Organize raw data by charting data using charts and graphs.
3. Analyze the charts (graphs) and extend the analysis into the
future.
4. Draw valid conclusions based on the research data.
Time:
2 Class Periods
Grade Level:
8-10
Key Concepts:
Scientific inquiry, data analysis, prediction
Definition of Terms:
Raw Data: Numbers that have not yet been
organized or analyzed into meaningful results.
Graphs: Diagrams that represent the numeric
differences in a variable in comparison with
other variables.
Bockground:
The data presented here were collected from
basic research on atmospheric gases long
before global climate change was a concern.
Scientists interested in a particular gas either
made or procured the right equipment, found a
suitable place to study the gas, then spent
several months setting up, calibrating, and
checking the data. Eventually, the "raw data"
accumulate and require analysis.
CLIMATE CHANGE AND THE GREENHOUSE GASES UNIT
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ACTIVITY 11
Just how the data are displayed is a question
the scientist doing the woik must deal with.
Study the examples provided as possible ways
to present the data (Figure 1). More detailed
The form - a chart, a line graph, a pie graph, or information on how the raw data were
a histogram - is often personal preference. gathered is included later in this activity.
Pie Graph
Carbon
Dioxide
CFCs
11 and 12
Line Graph
Bar Graph
Other CFCs 333
Nitrous
Oxide
Methane
• y » i •
. I I I I I I I I I I I I I I
58 60 62 64 66 68 70 72 74 76 78 80 82 84
Year
8688
800
o
]= 600
400
O
_o
'«?
1/3
'§ 200
r
' »
r .
' »
^^M
Part Compliance and High HCFC
Part Compliance and Reduced HCFC
Part Compliance and Technology Transfer 1992
Global Compliance 1992
97 Phase-Out for Developed Countries
97 Phase-Out and HCFC Phase-Out 1992
Faster Phase-Out Global
1990
2010
2030
2050
Year
Figure
1 . Examples of Different Ways to Display Data Graphically. Reproduced with permission
from Climate Change - The IPCC Scientific Assessment (1990), World Meteorological
Organization.
CLIMATE CHANGE AND THE GREENHOUSE GASES UNIT
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ACTIVITY 11
Activity:
Students will learn about changes that have
occurred in some greenhouse gas levels and
average annual temperatures within the recent
past. The student will make one or more charts
(graphs) of actual research data, find the
trends, extend the trend into the future, and
then draw a valid conclusion(s). The research
data will include values for temperature
change, carbon dioxide (CO2), methane,
nitrous oxide, and chlorofluorcarbons (CPCs)
in the atmosphere. The extension to this
activity provides information about the people
involved in these scientific discoveries.
Materials:
• Raw data (attached)
• Pencil
* Graph paper
• Ruler
Procedure:
To familiarize students with scientific
discoveries and the people behind them, have
them read the Extensions to this exercise
(Monitoring Carbon Dioxide: How Science Is
Done and Tlie Vostok Ice Core). Inform the
students that they have been assigned a
position in a research institution dealing with
global issues. A research scientist has just
given them some "raw data". Within the week
there is a major international conference on
this material and they need to analyze it by
then. The data need to be presented and
organized in a meaningful and useful way.
Divide the class into small research teams.
1. Discuss where data come from, types of
graphs available, what a trend is, and how
to project a trend.
2. Have students simulate the role of a
research scientists by telling them they
have been assigned to this project
3. Given the following data, have the students
plot the values and make the curve for at
least one graph. There are five different
graphs, therefore make sure that all five are
assigned so that each can be discussed.
4. Upon completion of the graph(s) have the
students continue the trend of the curve for
another 50 years.
5. Now have each student or student group
develop a conclusion for their particular
chart. Have students with the same graph
get together and compare graphs for
accuracy and conclusions.
6. Ask for a spokesperson for each type of
graph to report a consensus view and a
minority view for the interpretation of the
graph.
7. Discuss the role of data analysis in
scientific research. How do choices in
displaying data affect communication?
Student Learning Portfolio:
1. A plotted graph of one of the atmospheric
gases
2. A conclusion for the "raw data" provided
to them
CLIMATE CHANGE AND THE GREENHOUSE GASES UNIT
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ACTIVITY 11
Row Data:
Carbon Dioxide Concentrations
(in ppmv*), Mauna Loa, Hawafl
Methane Gas Concentration
Atmospheric Greenhouse Gas Affected
by Human Activities
Year
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
ppmv
314.8
316.1
317.0
317.7
318.6
319.1
319.4
320.4
321.1
322.0
322.8
324.2
325.5
326.5
327.6
329.8
Year
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
ppmv
330.4
331.0
332.1
333.6
335.2
336.5
338.4
339.5
340.8
342.8
344.3
345.7
346.9
348.6
351.2
Year
1850
1879
1880
1892
1908
1917
1918
1927
1929
1940
1949
1950
1955
1956
1957
1958
ppm*
0.90
0.93
0.90
0.88
1.00
1.00
1.02
1.03
1.13
1.12
1.18
1.20
1.26
1.30
1.34
1.35
Year
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
ppm*
1.45
1.47
1.50
1.52
1.55
1.56
1.58
1.60
1.60
1.61
1.62
1.63
1.65
1.67
1.69
1.72
*ppmv = Pans per million by volume.
*ppm = Parts per million.
Gaps in the record between 1958-1975.
CLIMATE CHANGE AND THE GREENHOUSE GASES UNIT
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ACTIVITY 11
CFG (chlorofluorocarbon)1 Production
Atmospheric Greenhouse Gas Affected
by Human Activities
Year
1955
1957
1959
1961
1963
1965
1967
1969
1971
1973
Amount2
100
120
140
150
150
200
225
290
320
375
Year
1975
1977
1979
1981
1983
1985
1987
1989
1991
Amount
350
360
330
325
320
340
300
305
310
Nitrous Oxide
Atmospheric Greenhouse Gas Affected
by Human Activities
'CFCs include the manufactured gas combinations
of chlorine, fluorine, and carbon. These gases were
never present in the Earth's natural atmosphere until
the 1930s.
2Values are in kilotons per year.
Year
1750
1760
1770
1780
1790
1800
1810
1820
1830
1840
1850
1860
1870
ppbv*
283.0
283.5
284.0
284.5
285.0
285.5
286.0
286.5
287.0
287.5
288.0
288.5
289.0
Year
1880
1890
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
ppbv*
289.5
290.0
291.0
292.0
292.5
293.0
294.0
295.0
297.0
299.0
305.0
310.0
* Values of N2O concentration are i» parts per billion
by volume (ppbv).
CLIMATE CHANGE AND THE GREENHOUSE GASES UNIT
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ACTIVITY 11
Temperature Deviation Over Time1
Year
1880
1885
1890
1895
1900
1905
1910
1915
1920
1925
1930
1935
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
Temp.
Deviation
-025
-027
-0.26
-0.29
-020
-0.38
-0.35
-0.33
-0.30
-0.15
0.00
-0.10
-0.05
0.05
-0.03
-0.01
0.05
-0.05
0.00
-0.05
0.15
0.18
021
Years
BF
200
1,000
5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
45,000
50.000
55,000
60,000
65,000
70,000
75,000
lemp.
Deviation
0.01
0.01
0.02
0.03
-0.83
-0.90
-0.80
-0.82
-0.70
-0.60
-0.75
-0.60
-0.45
-0.80
-0.82
-0.70
-0.70
Years
BF
80,000
85,000
90,000
95,000
100.000
105,000
110,000
115,000
120.000
125,000
130,000
135,000
140,000
145.000
150.000
155.000
160.000
lemp.
Deviation
-035
-030
-0.43
-0.52
-036
-0.40
-0.68
-0.64
-0.19
-0.09
0.03
0.10
-021
-0.75
-0.90
-0.82
-0.70
'For the purposes of this exercise, the mean avenge temperature from 1950 to 1980 is
used as i baseline for comparative purposes. Note the 5-year average deviation values for
the past 100 years, then the change to a 5,000-year spread for average deviation values.
The values beyond 100 years were taken from ice core readings made by a USSR team
of scientists working for years in the Vostok, Antarctic station.
2Years BP * years before present
CLIMATE CHANGE AND THE GREENHOUSE GASES UNIT
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ACTIVITY 11
Extension
Monitoring Carbon Dioxide:
How Science Is Done.1
Dr. Charles David Keeling
At the age of 26 and a new graduate of
Northwestern University, Charles David
Keeling went to work as a geochemist at
California Institute of Technology in Pasadena.
It was there that Keeling was to begin his life's
work on little more than a bet
Harold Brown, the man who had hired
Keeling, made a comment that the amount of
CO2 dissolved in freshwater is always in
balance with the amount of CO2 in the air
above the water. Hoping to spend more time
out of doors. Keeling challenged Brown's
assumption and asked to conduct an
experiment to test Brown's ideas.
Keeling spent the following winter and spring
developing a manometer to extract and
measure CO2 in parts per million. By the end
of Keeling's first year at Caltech (1955) his
manometer was ready. However, instead of
beginning his tests along streams and lakes as
the original study required, Keeling began
measuring CO2 levels on the grounds of
Caltech. His first measurement registered
315ppmCO2.
Keeling continued taking measurements of
C02 levels at Caltech every 4 hours for a
24-hour period. Keeling was on a roof at
Caltech gathering his second set of
measurements, when his wife Louise, gave
birth to their first son. Drew. After Drew's
birth, Keeling and his wife had similar evening
schedules - every 4 hours Keeling would
awaken to take the CO2 measurements and
Louise would awaken to tend to their new
baby.
During the summer of 1955, Keeling, Louise
and the infant Drew, camped at Big Sur,
Yosemite, the Inyo and Cascade mountains,
and the Olympic National Park, all the while
Keeling filled flasks with air from these very
different areas. After returning to the lab
Keeling found an interesting pattern in the CO2
levels of the flasks. He found that the CO2
levels rose in the evening and dropped in the
morning and afternoon.
Photosynthesis requires plants to take in CO2
all day long to build sugars for growth, repair,
reproduction. At the end of the day, however,
the plants have all the food they need and must
respire in order to use the CO2. In doing so,
plants release CO2 back to the atmosphere.
The puzzle of Keeling's measurements was
the mid-afternoon reading always measured
315 ppm - no matter where the measurement
was taken. It seemed logical that the amount of
CO2 might fluctuate a bit due to shifting >vind
patterns, or changes in location, but that was
not the case.
Later that year Keeling ventured back to
eastern California and the Inyo mountains with
more bottles to take more samples of the
winter air. At 12,000 feet, every 4 hours
Keeling took CO2 samples for 5 days. The
concentration of CO2 in these bottles sat right
at 315 ppm.
The reason? At that altitude the atmosphere
r ^ undergone significant mixing and is free of
local influences of forests, cities, cars,
industries. Keeling's findings suggested that
the Earth's global average for CO2 in 1955 was
'Wcincr, J. 1990. The Next Hundred Years: Shaping the Fate of Our Living Earth. New York, NY: Bantam Books.
CLIMATE CHANGE AND THE GREENHOUSE GASES UNIT
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ACTIVITY 11
315 ppm. So how was this related to Keeling's
afternoon readings of 315 ppm elsewhere?
Although forests are influenced by any
number of local conditions, generally, with the
warming of the ground in the morning and
early afternoon the air rises and is replaced by
cooler air from higher in the sky. This is air
that has been mixed so well that it represents
the atmosphere of the entire planet
Two weeks after Keeling had returned from
the Inyo mountains, he was in Washington,
DC, talking with scientists on what would be
needed to monitor CO2 levels on a global
scale. The International Geophysical Year
(ICY) was about to begin which would
involve 18 months of global observations of
earth air, water, fire, and ice. It was there that
Keeling was offered a station at Mauna Loa,
HI, to monitor CO2.
Hawaii is the most isolated area in the world.
The winds over it would represent a global
average, at least for the northern atmosphere.
The northern and southern atmospheres do not
mix well. According to Keeling's previous
measurements, it was expected that the first
measurement from Mauna Loa would register
315 ppm. In fact, the first reading was
314 ppm.
In the first few months of the new Mauna Loa
station the readings went up and down and
then the station had power shortages. Once the
station was finally up and running again the
CO2 measurements rose throughout the winter
and then began to drop in the following spring.
The first year's set of data when charted
looked like a side view of a roller coaster.
Keeling, however, believed he understood its
message.
Having observed firsthand the daily cycle of
C02, Keeling now believed he was observing
an annual cycle. Here, photosynthesis begins
in April, increases to a maximum in June, and
continually declines through October.
Respiration also peaks in June, however, it
continues throughout the rest of the year as
decomposition returns CO2 to the atmosphere.
Since that first year of data on Mauna Loa
several other stations have been set up in the
northern and the southern hemispheres to
record and monitor CO2 levels throughout the
world. The annual pattern that was observed in
the first year continues to occur, however, the
amounts of CO2 are increasing.
The first decade of record keeping showed the
CO2 levels to be increasing at a rate of 1 ppm
each year. After that, the data show that CO2
levels are increasing at a faster pace - about
1.5 ppm per year.
Since Keeling began his measurements in
1955, average CO2 levels have increased from
315 ppm to over 350 ppm. The trend indicates
the amount of CO2 in the Earth's atmosphere
will likely continue its increase.
When compared to global average
temperatures, both CO2 levels and average
temperatures are increasing. Is there a
connection? Many believe there is, and as a
result believe that the amount of CO2 being
pumped into the atmosphere from human
activities must be reduced or serious social and
environmental changes will ensue. For many
others the verdict is still out on this issue and
research is continuing at a feverish pace.
Keeling is still CO2 dioxide and continues his
work at Scripps Oceanographic Institute.
CLIMATE CHANGE AND THE GREENHOUSE GASES UNIT
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ACTIVITY 11
Extension
The Vostok Ice Core
Scientists have long sought ways of gathering
more direct evidence for conditions on the
ancient Earth than can be provided by
theoretical ideas and the fossil record. One
such method is the analysis of glacial ice cores
from Antarctica and the Greenland Ice Cap.
Snow that falls on the ice caps of Greenland
and Antarctica usually does not melt. Instead,
it slowly builds up, layer upon layer, for
hundreds and thousands of years. As the snow
accumulates and is compressed by the weight
of the layers above it into ice, it traps
minuscule bubbles of air. The surrounding ice
prevents the air from escaping and/or mixing
with air from the atmosphere above. As a
result, the gas trapped in the ice is truly "fossil
air", air from the atmosphere that existed at the
time the original snow fell. By digging deep
into the thick, persistent glaciers of Antarctica
and Greenland, scientists can directly sample
air from thousands of years ago.
Since the early 1970s, the Soviets and the
French have collaborated on research at
Vostok in Antarctica to drill and examine the
deepest ice core ever studied. The Vostok core
is over 2,000 meters long and samples ice
layers deposited as long ago as 160,000 years.
The core includes climatic information on the
ice age that ended about 8,000 years ago and
the ice age before it The Vostok core is
unique. It provides the most accurate CO2
historical information thus far.
Consider the enormous effort involved in
obtaining a core from a polar glacier. What
were the mechanics involved? What would be
some of the obvious hardships in undertaking
a project such as this?
The Soviets perfected a thermal technique of
drilling where the base of a 8m x 10 cm tube
was electrically heated to penetrate the ice
without damaging the core itself. In addition, it
was not easy to keep the hole vertical. The drill
had to descend carefully and excess water had
to be quickly recovered to keep from
refreezing (the average surface temperatures
there were minus 55 °C) and distorting the
sample. In the event the drill jammed for any
length of time, the relentless movement of the
Antarctic ice would deform the hole,
destroying the core. The engineers had to be
vigilant. It took 5 years (1980-1985) to extract
the core. The hole left behind by this sample
has been abandoned and another hole is soon
to be started with drilling equipment that may
probe even deeper than the original core,
allowing even more ancient atmospheres to be
sampled.
What the Vostok Core Revealed
Up until examination of this ice core, the
connection between CO2and changes in the
Earth's climate as a cause and effect
relationship could not be substantially
supported One reason was earlier core
samples only went back about 30,000 years
and did not contain sufficient information to
support CO2 as a cause of climate change.
Studying the Vostok core has shown a positive
relationship between increases in CO2and
warm periods of the Earth's past, as well as
correlations between ice ages and low amounts
of atmospheric COZ Similar studies have
shown that ice cores give reliable information
on atmospheric conditions. As a result, the
CLIMATE CHANGE AND THE GREENHOUSE GASES UNIT
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ACTIVITY 11
Vostok CO2 record provides evidence for a
connection between the Earth's global climate
system and the carbon cycle.
According to the researchers, the Vostok series
provides direct support for an interaction
between CO2, orbital forcing (a term used to
describe climate changes caused, or "forced",
by changes in Earth's orbit - e.g., the
Milankovitch theory*) and climatic changes.
However, they are cautious about this
interpretation because the core sample can
provide only circumstantial evidence linking
these factors. Data from the core cannot prove
cause-and-effect relationships.
*The Milankovitch theory suggests that changes in
the Earth's climate are related to variation in the
Earth's orbital features. The Earth's orbital shape
fluctuates at intervals of 90,000 years, the Earth's tilt
on its axis changes at intervals of 41,000 years, and
the Earth wobbles on its axis at intervals of 19,000
to 23,000 years. The fossil record indicates hat
significant changes in the Earth's climate and types
of organisms closely follow these cycles.
160,000-Year Record
The following information is extrapolated
from a series of articles published in Nature
(1987).
1. The CO2 record seems to exhibit a cyclic
change in periods of about 21,000 years.
These cycles may be related to the 20,000
intervals described above in the
Milankovitch theory. The researchers are
very hesitant about this cycle, but it is
interesting to note and discuss with your
students.
2. The scientists took the ice core samples
and crushed them under a vacuum,
releasing the trapped gas which was then
analyzed by a very sensitive gas sample
chemical analyzer called a gas
chromatograph. The scientists also
measured deuterium (a heavy isotope of
hydrogen) and an isotope of oxygen (18O).
Both of these are good indicators of
temperature change; however, deuterium is
a better indicator than is I80. The amounts
of deuterium and CO2 found in the ice core
are directly related to the average global
temperature at the time the gas was trapped
in the ice.
3. The ice core covers the past 160,000 years
and includes the Holocene (the last glacial
period) the previous interglacial period, and
the end of the penultimate (next to last)
glaciation.
4. The CO2 record exhibits the following:
a. Two very large changes - one near the
most recent part of the record, about
15,000 years ago, the other about
140,000 years ago.
b. The high levels are comparable with the
"pre-industrial" CO2 levels that
prevailed about 200 years ago. The low
level ranges among the lowest values
known in the geologic record of CO2
over the last 10 million years.
c. The two large changes in CO2
correspond to the transitions between
full glacial conditions (low CO2) of the
last and the penultimate glaciations, and
the two major warm periods (high CO2)
of the record: The Holocene and the
previous interglacial period.
CLIMATE CHANGE AND THE GREENHOUSE GASES UNIT
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ACTIVITY 11
References:
Calder, N. 1983. Timescale:AnAtlasofthe
Fourth Dimension. New York, NY: Viking
Press.
Bamola, J.M., D. Raynaud, YS.
Korothkevitch, and C. Louis. 1987. Vostok ice
core provides 160,000-year record of
atmospheric CO2. Nature 329:408-414.
Genthon, C., J.M. Bamola, D. Raynaud, C.
Lorius, J. Jouzel, N.I. Barkov, Y.S.
Korothkevich, and V.M. Kotyakov. 1987.
Vostok ice core: Climatic response to CO2 and
orbital forcing changes over the last climatic
cycle. Nature 329:414-418.
Jouzel, J., C. Lousi, J.R. Petit, C. Genthon, N.I.
Barkov, V.M. Kotyakov, and V.M. Petrov.
1987. Vostok ice core: A continuous isotope
temperature record over the last climatic cycle
(160,000 years). Nature 329:403-408. Q
Notes:
CLIMATE CHANGE AND THE GREENHOUSE GASES UNIT
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ACTIVITY 11
Notes:
CLIMATE CHANGE AND THE GREENHOUSE GASES UNIT
-------
How Do Scientists Analyze
Greenhouse Gases and Global
Temperature Data Over Time?
SruDENTGuiDE—ACTIVITY 11
Definition of Terms:
Raw Data: Numbers that have not yet been organized or analyzed
into meaningful results.
Graphs: Diagrams that represent the numeric differences in a
variable in comparison with other variables.
Activity:
You have been assigned a position in a
research institution that addresses global
issues. A research scientist has just given you
s >me "raw data". Within the week there is a
rnajor international conference on this material
and you must analyze it by then. The data
need to be presented in a meaningful and
useful way. Working with your team, organize,
analyze, and present your data.
Materials:
• Raw data
• Pencil
• Graph paper
• Ruler
Procedure:
1. Plot the values and make a graph using the
data your teacher provides.
2. Upon completion of the graph(s), continue
the trend shown in your diagram for
another 50 years (i.e., make a prediction on
how you would expect the graph to look
with 50 more years of data).
3. Develop a conclusion for your chart. If
other students in your class are working
with the same data, get together and
compare graphs for accuracy and
conclusions.
4. Share your findings with the class.Q
CLIMATE CHANGE AND THE GREENHOUSE GASES UNIT
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SiuDENiGuiDE—ACTIVITY 11
Notes:
CLIMATE CHANGE AND THE GREENHOUSE GASES UNIT 90
-------
How Does Human Activity Contribute to
Greenhouse Gas Increases?
ACTIVITY 12
Lesson Focus:
What are the important sources of anthropogenic (human-caused)
emissions of greenhouse gases (GHGs)?
Objective:
The student will be able to:
1. Identify anthropogenic sources of GHGs.
2. Describe the increasing magnitude of anthropogenic GHGs.
3. Explain the U.S. contribution to increasing GHGs in the
atmosphere.
4. Calculate individual levels of CO2 emissions.
5. Analyze the influence of personal CO2 contributions on larger
scales.
Time:
1 class period
Grade Level:
8-10
Key Concepts:
Greenhouse gases, global emissions, personal CO2 contributions,
data analysis
Definitions of Terms:
Anthropogenic: Human-caused.
Anthropogenic sources of pollution, for
example, are human-caused sources (industry,
automobiles, etc.).
Greenhouse Gases: Gases found in Earth's
atmosphere, generally in small (or "trace")
amounts that absorb and retain heat
Anthropogenic greenhouse gases include CO2,
methane (CH4), chlorofluorocarbons (CFCs),
and nitrous oxide (N2O).
Background:
Many scientists believe that human activity is
altering the composition of the atmosphere by
CLIMATE CHANGE AND THE GREENHOUSE GASES UNIT
91
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ACTIVITY 12
increasing the concentration of greenhouse
gases. It is important to remember that the
greenhouse effect is what keeps Earth warm
enough to be habitable. The current concern is
directed at an enhanced greenhouse effect, one
that would put more heat-absorbing gases into
the atmosphere and thereby increase global
temperatures. The enhanced greenhouse effect
has been linked to human activities that result
in increased greenhouse gas emissions.
Nitrogen (78%) and oxygen (21%) together
constitute 99% of the atmosphere. Most of the
remaining 1 % (consisting of a number of
different gases collectively classified as "trace"
gases due to their low concentrations) is
composed of greenhouse gases. The recent
attention given to the greenhouse effect and
global warming is based on the recorded
increases in concentrations of some of these
trace gases due to human activity.
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360
340
320
300
280
260
310
300
290
i i r
Carbon Dioxide
280
II I
Nitrous Oxide
_L
Anthropogenic Sources
Carbon dioxide (CO2) is considered to be the
most important GHG. It arises primarily from
the burning of fossil fuels (motorized vechiles,
electric power plants, homes heated with gas
or oil) and the burning and clearing of forested
land for agricultural purposes.
Methane (CH4) is largely a product of natural
biologic processes, but their output can be
accelerated by human activities. CH4 is
emitted from the decay of organic matter in
waterlogged soils (e.g., wetlands, rice paddies)
and from the digestive tracts of grazing
animals (e.g., ruminants). The additions from
human activities include the expansion of rice
agriculture, the increased number of livestock,
increased number of landfills, and leakage
from natural gas pipelines.
Chlorofluorocarbons (CFCs) have no natural
source; they are produced entirely by human
1750 1800
1850 1900
Year
1950 2000
.2
1800
1600
1400
0.1200
a
o
U "1000
,0
u
o
U
800
600
0.3
0.2
Methane
D.
D.
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CFC11
1750 1800
1850 1900
Year
1950 2000
Reproduced with permission for Climate Change - The IPCC Scientific Assess^'nt (1990), World
Meteorological Organization.
CLIMATE CHANGE AND THE GREENHOUSE GASES UNIT
92
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ACTIVITY 12
Carbon
Dioxide
Other
Regional Contributions to the
Greenhouse Effect
India.
Rest
of World
activity. CFCs are used widely as refrigerants Human Contributions
in air conditioners, refrigerators, freezers, and to the Greenhouse Effect
heat pumps. They are found in some foam Nitrous
plastics and used in some electronics Oxide
manufacturing.
Nitrous Oxide (N£>) is emitted from coal-
burning power plants and can be released from
the breakdown of chemical fertilizers in the
soil.
The concentrations of each of these GHGs is
increasing. However, the increase in emissions
is not uniformly distributed globally. Most of
the emissions come from the more developed
countries, where power generation, power
consumption, and living standards are highest.
Activity:
Students will examine graphs of GHG
emissions and their increases associated with
human activity. The focus will be on CO2,
CH4, N2O, and CFCs. Using graphs and tables,
the students will examine global sources of
GHGs. Students will then calculate some
personal contributions to increases in one of
the GHGs: CO2.
Materials:
• Graphs, charts, and tables of GHGs
• City map
• Calculator
Procedure:
1. Brainstorm possible anthropogenic sources
of GHG
2. Read and discuss charts and graphs
3. Encourage the students to compare the
GHG graphs with other graphs (e.g., global
temperature, human population increases)
during the same time span. Students should
CFCs
Methane
China
European
Economic
Community
USSR
USA
Reproduced with permission for Climate Change
The IPCC Scientific Assessment (1990), World
Meteorological Organization.
be encouraged to come up with their own
comparisons. What kinds of trends do they
predict? Can seemingly upward trends be
reversed?
4. Ask students to discuss global emissions of
GHGs. For example, the United States has
only a small percentage of the world's
CLIMATE CHANGE AND THE GREENHOUSF GASES UNIT
93
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ACTIVITY 12
population but emits a disproportionate
share of the global CO2. China has a
population of over a billion people. What
would happen if they "developed" to the
point where most families owned an
automobile that was also emitting CO2?
5. Calculate personal/family/class
contribution of CO2 due to vehicle use by
. using the following steps:
a. Have each student estimate (with the
help of a city map, if necessary) how
far it is from their home to school (in
miles).
b. Have each student identify their type of
family vehicle based on the types listed
in the table below.
c. Each student will then calculate the
amount of gas used weekly //they rode
to and from school everyday in a
private car. To do this, add up the total
number of miles for 10 round trips to
school (remember, each time they are
dropped off at school, the driver has to
drive home, so there are 2 round trips a
day), divide the total by the miles per
gallon to determine the gallons of gas
bumed, then multiply the result by the
CO2 released per gallon. Example: If
you live 4 miles from school, your car
travels 16 miles per day to drop you off
and pick you up, or 80 miles per week.
If it is a full-size car, that will bum 5
gallons of gas. Five gallons of gas will
produce 100 pounds of CO2 every
week!
d. Add the class total.
e. Have those students that ride the bus do
the same calculation again, only this
time using the figures for the bus, and
dividing the total CO2 released by the
approximate number of students that
ride on the bus.
f. Determine how many students walk to
school. Subtract the CO2 contributions
from those students, and correct the
CO2 contributions for those that ride
buses. Recalculate the class total and
compare the results.
Typical Vehicle CO2 Emission Rates
Vehicle
Compact car
Full-size car
Truck/van
Bus
mpg
24
16
13
8
Pounds
CO,
per Gallon
20
20
21
22*
*Buses add more CO2 per gallon, but they carry more
passengers, so be sure to consider contribution by
passenger, not just vehicle.
Student Learning Portfolio:
1. Copies of graphs and explanations in logs
2. Class CO2 calculation
References:
The CO2 You Spew, Super Science Blue.
Scholastic, February 1991. Q
CLIMATE CHANGE AND THE GREENHOUSE GASES UNIT
94
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How Does Human Activity Contribute to
Greenhouse Gas Increases?
STUDENTGUIDE—ACTIVITY 12
Definitions of Terms:
Anthropogenic: Human-caused. Anthropogenic sources of
pollution, for example, are human-caused sources (industry,
automobiles, etc.).
Greenhouse Gases (GHGs): Gases found in Earth's atmosphere,
generally in small (or "trace") amounts mat absorb and retain heat
Anthropogenic GHGs include carbon dioxide (CO2), methane
(CH4), chlorofluorocarbons (CFCs), and nitrous oxide (N2O).
Activity:
You will use information (provided in the form
'of graphs and tables) on GHG emissions and
their increases associated with human activity
to discuss and analyze global sources of
GHGs. You will then calculate some of your
own personal contributions to increases in one
of the GHGs - CO2 - and analyze the
magnitude of your contributions, along with
those of your class.
Materials:
• Graphs, charts, and tables of GHGs
• City map
• Calculator
Procedure:
1. With your class, discuss possible
anthropogenic sources of GHGs. Where do
you mink these gases come from? Are the
sources common all over the world, or are
some areas (or societies) larger sources
than others?
2. Read and discuss charts and graphs
provided by your teacher. How does the
information in these support or contradict
the conclusions you reached during the
brainstorming session?
3. Compare the GHG graphs with other
graphs (e.g., global temperature, human
population increases) collected by the class
or provided by your teacher. Compare the
information in these with the GHG graphs.
Do you see any common trends? Is there
any basis for linking the GHG data with
population data or temperature data?
4. Discuss with the class the pattern of global
emissions of GHGs. For example, the
United States has only a small percentage
of the world's population but emits a
disproportionate share of the global COr
China has a population of over a billion
people. What would happen if they
CLIMATE CHANGE AND THE GREENHOUSE GASES UNIT
96
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STUDENTGUIDE— ACTIVITY 12
"developed" to the point where most
families owned an automobile that was
also emitting CO2?
5. Calculate your own personal contribution
of CO2 due to vehicle use by using the
following steps:
a. Estimate as closely as possible how far
you travel between school and home (in
miles) on a daily basis (use a city map,
if necessary).
b. Use the table below to identify the type
of vehicle (if any) you use to get to and
from school.
c. Calculate the amount of gas used
weekly if you rode to and from school
everyday in a private car. To do this,
add up the total number of miles for 10
round trips to school (remember, each
time you are dropped off at school, the
driver has to drive home, so there are 2
round trips a day), divide the total by
the miles per gallon to determine the
gallons of gas burned, then multiply the
result by the CO2 released per gallon.
Example: If you live 4 miles from
school, your car travels 16 miles per
day to drop you off and pick you up, or
80 miles per week. If it is a full-size car,
that will bum 5 gallons of gas. Five
gallons of gas will produce 100 pounds
of CO2 every week!
d Add your estimate to the class total
being recorded by your teacher.
e. If you ride the bus, do the same
calculation again, only this time use the
figures for the bus, and divide die total
CO2 released by the approximate
number of students that ride on the bus.
Your teacher will then subtract the
amount of C02 that you calculated in
step "c" from the class total, and
substitute the new amount you
calculated based on bus use.
f. If you walk or bike to school, you will
contribute no additional CO2 to the
atmosphere for your travel. Your
teacher will subtract the amount you
calculated in step "c" above from the
class total.
g. Contrast the class total calculated as if
each student used a private car for
transport to and from school with the
total that included bus, bike, and
walking. How much difference is there?
How many students don't use private
cars for school transport?
Typical Vehicle CO2 Emission Rates
Vehicle
Compact car
Full-size car
Truck/van
Bus
mpg
24
16
13
8
Pounds
C02
per Gallon
20
20
21
22*
•Buses add more CO2 per gallon, but they carry more
passt agers, so be sure to consider contribution by
passenger, not just vehicle D
CLIMATE CHANGE AND THE GREENHOUSE GASES UNIT
96
-------
How Might Elevated OX Affect Plants?
ACTIVITY 13
Lesson Focus:
Plants use CO2 as a nutrient, absorbing it through the process of
photosynthesis. Do plants respond to increasing CO2? If so, how do
they respond?
Objective:
The student will be able to:
1. Conduct an experiment on the effect of elevated CO2 on plants.
2. Explain the use of a "control" in scientific experimentation.
3. Analyze observed data and record results.
4. Form reasoned opinions about the relationships between CO2,
plants, and climate change.
Time:
• 1 class period for setup
• 3-4 weeks of daily care (5 minutes a day)
• 1 class period for observation/discussion
Grade Level:
8-10
Key Concepts:
Carbon dioxide, plant growth, experimentation, data gathering
Definitions of Terms:
Photosynthesis: The process used by plants to
convert atmospheric carbon dioxide (CO2) into
sugars utilizing energy derived from sunlight
The sugars can be further converted into
organic compounds needed for plant growth or
can be used as an energy source for the plant
Carbon Sequestering: The act of removing
carbon from the atmosphere and storing it for
long periods of time. Long-lived forest trees
are natural carbon sequesterers in that they use
POSSIBLE EFFECTS UNIT
atmospheric CO2 to build woody tissue. That
tissue will retain the carbon as long as the tree
is alive (for hundreds of years in certain
species). In contrast, annual plants (like wheat
or com) will only store carbon for one growing
season, then release it as they die and decay at
the end of the season.
Background:
Plants depend on a steady supply of
atmospheric CO2 for survival. Through the
process of photosynthesis, plants take CO2 out
97
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ACTIVITY 13
of the air and turn it into sugars, starches, and
other organic molecules. Many plants benefit
from increasing CO2, increasing growth rates,
size, and yield in response, as long as there is
sufficient light, water, and other nutrients to
support the growth. Different species respond
differently, with some species responding far
less than others. The projected increases in
atmospheric CO2 over the next century may
double the average global concentration from
approximately 350 ppm (parts per million) (in
1990) to 700 ppm (by the end of the next
century). Recent experiments have suggested
that many plants will likely respond to such an
increase with increased growth, if all other
environmental conditions remain the same.
This exercise is designed to demonstrate the
principle that increased CO2 can act to enhance
plant growth. Because the plant response
should be rapid and obvious, and cannot
depend on elaborate CO2 control or
monitoring equipment, we will use human
breath (which contains approximately
10,000 ppm CO2) as our source of extra CO2.
To enrich the CO2 environment around plants,
we will grow them in small enclosed chambers
and add human breath to the chambers on a
regular basis.
Activity:
Students will plant, care for, and observe the
changes in growing plants under conditions of
ambient (normal) CO2 and increased levels of
C02.
Materials:
For each team of two students:
• Two soda bottle "experimental chambers"
(see Activity 6 page 43)
• One plastic saucer for each bottle
• Knife, scissors, tape
• Potting soil sufficient to fill the bottle
bottoms
• Seeds of several different species of plants
(tomato, wheat, bean, cucumber, clover, etc)
• Water-soluble plant food
• Straws
• Hand pump (often sold as balloon pumps or
aspirators)
Procedure:
1. Fill the plastic bottoms with potting soil
and set in the saucers. Water the soil so that
it is very moist.
2. Each team should select a plant type to
work with from the seeds available. Plant
two seeds in each pot, and plant at least two
pots, one to add CO2 to and one with
normal CO2 to serve as a control. Leave the
bottle tops off until the seedlings emerge.
Make sure that each plant species is
selected by two or more teams to allow
conclusions to be checked between teams.
3. After 2-4 days the seedlings should
emerge. Thin the seedlings to one per pot
and place the bottle tops on each pot. Label
one bottle "+CO2". and the other "Normal
CO2". Set the bottles in a bright place.
Once you place the bottles on the pots, the
bottles will serve to trap the moisture
inside, so you should be careful not to
overwater the plants.
4. CO2 Treatment: Beginning now, and for
each school day for the next 3 weeks,
enrich the CO2 in the' V bottle by blowing
10 breaths into the bottle through a straw
(Figure 1). Leave the caps off of both
bottles, but to reduce the extra CO2 leakage
POSSIBLE EFFECTS UNIT
98
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ACTIVITY 13
out of the top of the bottle cover
approximately half the opening with a
piece of tape. Although some air will
exchange through the opening, the extra
CO2 will mostly remain in the bottle.
Control Treatment: In order to ensure that,
except for the extra CO2, both treatment
groups are exposed to the same conditions,
the Control group will also have air added,
at the same time the extra CO2 is put into
the other group. To add air without adding
additional CO2, use the hand pump to
gently pump room air into the bottle (pump
approximately 25 times per bottle).
Breath or
Room Air
I
Drinkjr>g
Straw
?^ffe^&s
tl*^2$>.><\'?jM
Chamber
Planter
Saucer
Figure 1. Completed Bottle Chamber Assembly
Remind the students not to hold the intake
of the hand pump near their faces so that
they don't pump their exhaled breath into
the control bottles.
5. Have the students describe the
experimental setup and CO2 enrichment
technique, and record observations of the
plant and bottle conditions in a logbook
throughout the experiment
6. Water the plants when necessary by adding
water to the saucers. Do not pour water into
the top opening or remove the bottle top
from the base. Water with a water-soluble
plant food each time.
7. At the end of 3 weeks, remove the
bottles from the bases, measure the heights,
number of leaves, and any other growth
parameter of interest. Each student team
will record these values in their logs and
share their results with the class. Be
prepared for some plants responding more
than others. If the responses generally seem
small, it may be because other factors had
limited the plant growth (e.g., There was
not enough light, water, or nutrient to
support good growth.) Be prepared to
discuss these. As with any true experiment,
there may be unexpected results.
8. Discuss the results. Consider the following
questions:
A. For the plants that grew better under
high CO2, do these results mean that
they will benefit from global wanning?
They might, if all other growth
conditions were favorable.
B. What about the additional effect of
changing weather (heat, drought, etc.)?
Unfavorable weather conditions (high
POSSIBLE EFFECTS UNIT
99
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ACTIVITY 13
temperatures, drought) would reduce
the capacity of the plant to benefit from
the additional COr whereas conditions
that might favor growth (such as
warmer weather in a cold area, or more
rainfall in a dry area) may enhance it.
C. If plants respond to more CO2 by taking
more in, might they take enough in to
reduce the CO2 concentration in the
atmosphere?
Yes, they might, if sufficient long-lived
plants such as forest trees respond to
the CO2, and if enough forests are
either re-planted or protected from
land-use changes.
If so, what will happen to the CO2 when
the plants die?
Decay of the plant tissue will release
the CO2 back to the atmosphere. Annual
plants return their fixed carbon back to
the atmosphere within a year,
perennials, especially long-lived trees
may hold, or sequester the carbon for
many decades.)
D. If you had to select plants that would
take C02 out of the atmosphere and
hold it for extended periods, what
would you select?
From the answers above, it is clear that
long-lived, fast growing trees or other
woody perennials would be the best
selections for carbon sequestering.
Scientists and policymakers are
currently exploring the scientific, social,
and economic factors that should be
considered in beginning planetary
reforestation programs to reduce CO2
buildup.
Student Learning Portfolio:
1. Description of the experiment,
observations, and final data in the student
log.
2. Written summary of class results in log.
Which plants responded, how did they
respond, etc.
3. Written answers to question for discussion.
Extensions:
Students may try many different experiments
using this bottle-exposure chamber system.
They may experiment with plants not
examined in class, they may try varying other
conditions such as less water, less nutrients,
and/or changing light levels.Q
Notes:
POSSIBLE EFFECTS UNIT
100
-------
How Might Elevated CO2 Affect Plants?
SiuDENiGuiDE—ACTIVITY 13
Definitions of Terms:
Photosynthesis: The process used by plants to convert atmospheric
carbon dioxide (CO2) into sugars utilizing energy derived from
sunlight. The sugars can be further converted into organic
compounds needed for plant growth or can be used as an energy
source for the plant
Carbon Sequestering: The act of removing carbon from the
atmosphere and storing it for long periods of time. Long-lived forest
trees are natural carbon sequestercrs in that they use atmospheric
CO2 to build woody tissue. That tissue will retain the carbon as long
as the tree is alive (for hundreds of years in certain species). In
contrast, annual plants (like wheat or com) will only store carbon for
one growing season, then release it as they die and decay at the end
of the season.
Activity:
You will plant, care for, and observe the
changes in growing plants under conditions of
ambient (normal) CO2 and elevated CO2.
Materials:
For each team of two students:
• Two soda bottle "Experimental Chambers"
• One plastic saucer for each bottle
• Knife
• Scissors
• Tape
• Potting soil sufficient to fill the bottle
bottoms
• Seeds
• Water soluble plant food
• Straws
• Hand pump
Procedure:
1. Fill the plastic bottoms with potting soil
and set in the saucers. Water the soil so that
it is very moist
2. Each team should select a plant type to
work with from the seeds available. Plant
two seeds in each pot, and plant at least two
pots, one to add CO2 to and one with
normal CO2 to serve as a control. Leave the
bottle tops off until the seedlings emerge.
3. After 2-4 days, the seedlings should
emerge. Thin the seedlings to one per pot
and place the bottle tops on each pot. Label
one bottle "+CO2", and the other "Normal
POSSIBLE EFFECTS UNIT
101
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STUDENTGUIDE—ACTIVITY 13
CO2". Set the bottles in a bright place.
Once you place the bottles on the pots, the
bottles will serve to trap the moisture
inside, so you should be very careful not to
overwater the plants.
4. CO2 Treatment: Beginning now, and for
each school day for the next 3 weeks,
enrich the CO2 in the ' V bottle by blowing
10 breaths into the bottle, through a straw
(Figure 1). Leave the caps off of both
Breath or
Room Air
Drinking
Straw
Chamber
Planter
Saucer
Figure 1. Completed Bottle Chamber Assembly
bottles, but to reduce the extra CO2 leakage
out of the top of the bottle cover
approximately half the opening with a
piece of tape. Although some air will
exchange through the opening, the extra
CO2 will mostly remain in the bottle.
Control Treatment: In order to ensure that,
except for the extra CO2, both treatment
groups are exposed to the same conditions,
the Control group will also have air added,
at the same time the extra C02 is put into
the other group. To add air without adding
additional CO2, use the hand pump to
gently pump room air into the bottle (pump
approximately 25 times per bottle).
5. Describe the experimental set-up and CO2
enrichment technique, and record
observations of the plant and bottle
conditions in a logbook throughout the
experiment.
6. Water the plants when necessary by adding
water to the saucers. Do not pour water into
the top opening or remove the bottle top
from the base. Water with a water-soluble
plant food each time.
7. At the end of three weeks, remove the
bottles from the bases, measure the heights,
number of leaves, and any other growth
parameter of interest. Record the values in
your logbook. Be prepared to share your
results with the class.Q
POSSIBLE EFFECTS UNIT
102
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What Impact Might
Sea Level Rise Have?
ACTIVITY 14
Lesson Focus:
How might thermal expansion of the oceans affect sea level?
Objective:
The student will be able to:
1. Describe the change in water level when the water is exposed to
heat.
2. Differentiate between thermal expansion and melting snow and
ice fields as they relate to sea level rise.
3. Predict the impact of rising sea level on coastal areas.
Time:
IDay
Grade Level:
8-10
Key Concepts:
Sea level rise, thermal expansion, ice and glacial melting
Definition of Terms:
Thermal Expansion: When most substances
are heated, their volume increases due to
increasing vibrations in their component
molecules. In the case of oceanic thermal
expansion, as the water molecules are warmed,
the volume of water increases.
Sea Level: The level of the ocean surface
water midway between high and low tide
levels.
Land-Based Ice Fields: Ice fields that lie on
top of land masses. Examples include
mountain glaciers, the Antarctic ice sheet, and
POSSIBLE EFFECTS UNIT
the Greenland ice sheet. Melting of these ice
fields would add water to the ocean, thus
raising sea level.
Floating Ice Caps: Packed ice that covers the
sea surface. The Arctic Ocean is generally
covered by floating ice caps. Melting of polar
ice caps would not have an impact on sea level
because this ice is already floating, thus
displacing its volume in the water.
Background:
If global temperature increases, many
scientists have indicated that an increase in sea
103
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ACTIVITY 14
level is one of the most likely secondary
effects. Two factors will contribute to this
accelerated rise in sea level. First, although the
oceans have an enormous heat storage
capacity, if global atmospheric temperatures
rise, the oceans will absorb heat and expand
(thermal expansion) leading to a rise in sea
level. Second, warmer temperatures will cause
the ice and snov/fields to melt, thereby
increasing the amount of water in the oceans.
It should be noted that only the melting of
land-based ice and snow fields (i.e., ice fields
of Antarctica, mountain glaciers) will increase
sea level. The melting of floating ice (i.e.,
North Polar ice cap) will not affect sea level.
(Tliis can be demonstrated to your students by
partially filling a glass container with water and ice
cubes and marking the water level on the glass. When
the ice cubes melt, note that the water level has not
clianged.]
Throughout the Earth's liistory there have been
periods of glaciation followed by warming
trends in which the glaciers retreated toward
higher altitudes and higher latitudes. At
present, glaciers throughout the world are
receding and the masses of ice at both polar
regions appear to be shrinking. The present
interglacial warming period began
approximately 14,000 years ago. At that time,
sea levels were 75 to 100 meters below present
levels. As the massive snow and ice fields of
the world began to melt, sea level rose rapidly
at rates of as much as I meter per century.
Over time, the rate of sea level rise declined to
the present rate of 10 to 15 centimeters a
century.
An accelerated rise in sea level would inundate
coastal wetlands and lowlands, increase the
rate of shoreline erosion, exacerbate coastal
flooding, raise water tables, threaten coastal
structures, and increase the salinity of nvers,
bays, and aquifers. Even though sea level rise
is considered to be one of the more likely
effects of global warming, there's still no
scientific certainty as to the rate or amount of
sea level rise.
Activity:
The students will conduct an experiment that
demonstrates the effect of thermal expansion
on water level. Discussion groups will follow
this activity as students explore the potential
impact of sea level rise on a global and local
scale.
Materials:
For each team of students:
• Conical flask
• Two-hole cork for flask
0 Thin, glass tube
• Long thermometer
• Portable, clamp-on reflector lamp
• 150-Watt floodlight
• Dye
Procedure:
1. Divide students into small teams.
2. Completely fill the flask with very cold
water (to improve visibility, dye can be
added).
POSSIBLE EFFECTS UNIT
104
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ACTIVITY 14
3. Place the cork in the stopper. Slide the
thermometer and glass tube in the holes in
the cork (Figure 1). The water should rise a
short way into the tube. Have students
record both the temperature of the water
and the water level in the glass tube in their
log books.
Thin Glass Tube
Thermometer
4. Ask students to predict what will happen to
the water level when exposed to heat.
Record prediction in logbook. Place the
flask under the lamp (Figure 2). 1\im on the
lamp and record measurements every 2
minutes.
Light Source
Cork
Figure 1. Thermometer and
Glass Tube Inserted
in Cork Holes
Thin Glass Tube
Thermometer
Completely Fill
with H2O
Figure 2. Experimental
Apparatus Placed
Under the Light Source
POSSIBLE EFFECTS UNIT
105
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ACTIVITY 14
Discussion:
• Why did the level of water in the flask
change?
As water warms, it expands.
• What implications does this experiment
suggest might occur if the oceans warm?
If the ocean temperatures warm sufficiently
to cause expansion, sea level would rise
thus inundating coastal wetlands and other
coastal low-lying areas.
Challenge your students to consider the
possible impacts of sea level rise in areas
such as South Florida or Bangladesh.
• If global warming is not sufficient to cause
significant snow and ice melt, would you
expect this thermal expansion to be enough
to cause coastal flooding and erosion
problems?
No, it will likely be enough to measure, but
not enough to cause significant coastal
problems.
• Which would you expect to have a greater
affect on sea level - the melting of the North
Polar or South Polar ice caps?
Would it make a difference? Why? North
Polar melting would have little effect on sea
level. That ice is already floating, thus
displacing its volume in water. If the South
Polar ice cap melted, the water would run
off the Antarctic continent into the ocean,
increasing the ocean volume (and sea level)
substantially.
Challenge your students to design an
experiment using ice cubes to test this idea.
Student Learning Portfolio:
1. Graph of the thermal expansion
experiment
2. A summary of the discussion questions in
lab notebook G
Notes:
POSSIBLE EFFECTS UNIT
106
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What Impact Might
Sea Level Rise Have?
SiuDENiGuiDE—ACTIVITY 14
Definitions of Terms:
Thermal Expansion: When most substances are heated, their
volume increases due to increasing vibrations in their component
molecules. In the case oceanic of thermal expansion, as the water
molecules are wanned, the volume of water increases.
Sea Level: The level of the ocean surface water midway between
high and low tide levels.
Land-Based Ice Fields: Ice fields that lie on top of land masses.
Examples include mountain glaciers, the Antarctic ice sheet, and the
Greenland ice sheet. Melting of these ice fields would add water to
the ocean, thus raising sea level.
Floating Ice Caps: Packed ice that covers the sea surface. The Arctic
Ocean is generally covered by floating ice caps. Melting of polar ice
caps would not have an impact on sea level because this ice is
already floating, thus displacing its volume in the water.
Activity:
You will conduct an experiment that
demonstrates the effect of thermal expansion
on water level. Discussion groups will follow
this activity as you explore the potential
impact of sea level rise on a global and local
scale.
Materials:
For each team of students:
• Conical flask
• Two-hole cork for flask
• Thin, glass tube
• Long thermometer
• Portable, clamp-on reflector lamp
• 150-Watt floodlight
• Dye
Procedure:
1. Working with your team, completely fill
the flask with very cold water (for
increased visibility, dye can be added to the
water).
2. Place the cork in the stopper. Slide the
thermometer and glass tube in the holes in
the cork (Figure 1). The water should rise a
POSSIBLE EFFECTS UNIT
107
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STUDENTGUIDE—ACTIVITY 14
short way into the tube. Record both the
temperature of the water and the water
level in the glass tube in your Jog books.
Thin Glass Tube
Thermometer
Cork
Figure 1. Thermometer and
Glass Tube Inserted
in Cork Holes
Light Source
Thin Glass Tube
Thermometer
Completely Fill
with H2O
Figure 2. Experimental
Apparatus Placed
Under the Light Source
3. What do you think will happen to the water
level when exposed to heat? Record your
prediction in your logbook.
4. Place the flask under the lamp (Figure 2).
Turn on the lamp and record measurements
every 2 minutes.
Discussion:
• Why did the level of water in the fbu k
change?
• What implications does this experiment
suggest might occur if the oceans warm?
• If global warming is not sufficient to cause
significant snow and ice melt, would you
expect this thermal expansion to be enough
to cause coastal flooding and erosion
problems?
• Which would you expect to have a greater
affect on sea level—the melting of the
North Polar or South Polar ice capsTQ
POSSIBLE EFFECTS UNIT
108
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o
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ACTIVITY 6
Materials:
For each team of four students:
• Two soda bottle "experimental chambers"
(ir (sanctions page 43)
• Knife or scissors
• Tape
• Two thermometers
• One 150-wan floodlight bulb
• Clamp-on, portable reflector lamp
• Stand for lamp setup
• Graph paper
Procedure:
1. Introductory class discussion: Who has
been inside a greenhouse? What are they
like? What are they for?
2. Constructing a model
greenhouse. Organize
students into teams of four.
Each team should use
scissors to cut several
elongated vents (1x4
inches) in the sides of one
of the bottles (Figure 1).
The vents make the
greenhouse "leaky". Heat
will escape easily. Leave
the second bottle intact
3. The students will tape a thermometer
(using cellophane tape or light-colored
masking tape, not black electrical tape) to
the sides of each bottle (facing out). They
should make sure the bulb of the
thermometer is just above the top of the
opaque base (if the bulb is below the base,
the thermometer may record the heat
absorbed directly by the dark plastic, and
complicate the results). It is important that
Figure 1.
the two thermometers are reading the same
temperature before beginning the
experiment. If not, explain how they can
"zero" them by recording the difference
and adjusting for the difference when the
observations are made. The bottles should
be capped.
4. Have the students set up a graph of time
(in minutes) versus temperature upon
which to record their observations. The
temperature axis should be approximately
20 °C to 40 °C. Ask them to predict which
bottle do they think will get hotter? Why?
Record predictions in their logbook.
5. Each student will have a specific
responsibility during the experiment.
Working in pairs (one for the intact bottle,
one for the perforated
bottle), have one
students keep track
of time, and the
other student
record the
temperature
every two
minutes on
the graph.
6. Place both
bottles
approximately
6" away
from the
lamp with
the thermo-
meters facing away
from the light (Figure 2).
7. Turn on the light and begin collecting your
data. Continue the experiment for 20
minutes.
Figure 2.
GREENHOUSE EFFECT UNIT
41
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