Hold the Mold!

•	Grade Level

5-8

•	Subject Areas

Science
Health

•	Duration

20 minute intra
15 min experiment prep
10 min activity discussion
2 weeks for experiment
20 minute wrap up

•	Setting

Classroom

•	Skills

Observation
Collecting data
Communication

•	Vocabulary

Mold
Spores
Fungi
Humidity

•	Related Websites

www. e pa .g o v/m old/

www.epa.gov/children

www.cdc.gov/mold/

Summary

Students will learn about the different
kinds of mold and how it grows. They
will learn the health effects of mold and
how to help avoid the growth of mold.

Objectives:

Students will:

•	Understand what mold is and how it
grows

•	Observe the growth of different kinds
of food molds & understand how to
identify and prevent mold growth.

Materials:

•	Small paper plates

•	Sealable sandwich bags

•	5 apples or other fruit: quartered

•	Sliced bread, halved

•	Spray bottle with water

•	Permanent marker to ID bags

•	Tape to seal bags

•	Observation Worksheets
Materials Tip: Use older apples or fruit
"seconds" from a local orchard or
market

National Science Standards:

•	Unifying Concepts and Processes

-	Changes, constancy, and

measurement

-	Evidence, models, &

explanation

•	Science as Inquiry

-	Abilities necessary to do

scientific inquiry

•	Science in Personal & Social

Perspectives

-	Personal health

-	Science and technology in

society

-	Natural hazards

•	History & Nature of Science

-	Science as a human endeavor

-	Nature of science

Background:

What is mold?

Mold is the common name for many
kinds of tiny organisms called fungi.
There are thousands of types of molds
that can be found indoors and
outdoors. Different molds will grow in
colonies, living on dead organisms
such as decaying plants and animals,
as well as non-living materials such as
buildings, food, fabric and books.
Some molds even thrive on living
organisms as parasites. Molds play
an important part of the natural
decaying process of living organisms
in the natural world. However, they
may present a health risk in indoor
environments.

Molds need moisture to thrive and
usually grow and reproduce spores in
damp or moist places. Light and
temperature also impact mold growth
in different locations such as showers,
kitchens, damp basements, and
around windows. Mold travels by
releasing spores into the air. Spores
are reproductive structures that allow
organisms such as fungi to spread
and survive in almost any
environment. Mold spores float
through the air, landing on and
interacting with thousands of living
and non-living objects.

Figure 1. Mold spores magnified.


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What does mold look like?

Mold grows in many sizes, textures, and colors such
as white, black, green, blue, and orange. Spores
are released by mature mold that varies in color, or
may not be colorful at all. Each mold growth can be
different.

Figure 2. Moldy bread.

What are the health impacts of mold?

Spores from mold growth, while natural, can also
pose health risks. Some people, with or without
allergies, are very sensitive to mold or may become
sensitive to mold from single or repeated exposure.
Molds, mold spores, and pieces of mold may impact
a person's health by causing minor irritations such
as a runny nose or itchy, watery eyes to major
health concerns such as difficulty breathing, asthma
attacks, infections, fever, and major skin irritations.
The best way to reduce and prevent mold growth is
to control moisture. To reduce mold growth in
homes, schools and other buildings, it is important
to keep humidity levels low, between 30-60%. To
reduce excess moisture that mold needs to grow,
it's also important to repair leaks, completely clean
and remove any existing mold growth, ventilate
bathrooms, kitchens and basements that are more
prone to damp conditions, and use a dehumidifier to
remove moisture from the air if necessary. Outside,
mold may grow In damp, shaded areas with lots of
leaves or compost. People who are sensitive to
molds should be careful to avoid such places and
areas prone to lots of mold growth.

When cleaning and removing mold at home or in
school, use soap and hot water and always wear
gloves, and a breathing mask, if necessary. For
more information about mold and health concerns
about mold, visit http://www.epa.gov/mold.

Procedure:

Warm-Up:

Ask students if they have ever seen mold.
Discuss with students what mold is, where it
comes from, and what purpose it serves.

Show students a picture of moldy bread.
Introduce them to the sources and health
effects of mold.

Activity

To gain a clear understanding of what mold is,
looks like, how it grows and spreads, students
will conduct an experiment where they will
grow contained household mold samples to
observe and document.

1.	Have students work in pairs.

2.	Each pair gets a paper plate and a sealable
plastic bag. Have students write their name
and the date on their bag.

3.	Students should then put their paper plate
inside the bag, but not seal it yet.

4.	Instruct students to place one slice of apple
and one half slice of bread on their plate,
inside the bag.

5.	Students should use the water spray bottle
to moisten their bread with one spray into
the bag.

6.	Students then seal their bag and place tape
over the seal.

7.	Place bags on a shelf where they will get
warm, but not hot and can sit still for two
weeks.

8.	Instruct students that they are going to
observe their experiment bag for mold
growth. Each student gets worksheets to
observe and record their observations and
data each day for two weeks. Worksheets
include questions to help guide
observations and a place for students to
sketch a simple drawing of their
observations. Note: Sketches will not be
shared at the end of the experiment. They
are for the student to use as a data tool.
Teachers may elect to use digital cameras
to record daily mold growth progress and
change as well.

9.	At the end of two weeks, discuss what
happened to the apple and bread. What
changes were observed?


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Wrap Up

Review questions & discussion:

•	Did mold grow on the apple or bread first?

Mold tends to grow on the bread first.

•	How long did it take to see mold growth?

Answers may vary based on moisture and
temperature of the classroom. By the end of
the first week, mold growth should be visible.

•	What does the mold look like?

Mold growth may vary in color, but tends to
be white fuzzy spots that grow larger.

•	What color is the mold?

Mold will vary in color from white to green,
blue, or grey.

•	Texture: Is the mold fuzzy, lumpy, flat, shaped?

Texture is likely to be fuzzy and bumpy, but
will vary.

•	Does the mold spread from one object to the
other?

Once mold growth is established, it will
spread to other objects in the bag.

•	Do you notice different molds on different foods?

Mold growth will vary on food items used,
location, and temperature.

•	Why is it important that we not open the bags to
smell the mold?

It is very important that the bags stay sealed t
o prevent allergic reactions and the spread of
mold spores into the air. Once mold growth
is established in the bags, mold will start to
release spores. When breathed in, mold and
mold spores can trigger allergic reactions
and irritations for people who are sensitive to
them. Make sure to discard sealed
experiment bags at the end of the experiment
in the garbage.

•	Are there different types of mold? Are some more
harmful than others?

There are thousands of species of mold.

While all molds have the potential to cause
health effects, not all molds are toxic. Some
molds have beneficial uses to create things
like cheeses and medicines. The research
on molds that produce harmful toxins, called
mycotoxins, is on-going. Mold growth in a
building does not always indicate the
presence of toxic molds, but for health and
safety, mold should be removed right away.

•	What does mold need to grow and how can you
help prevent the growth of mold at home and in

school?

Mold needs moisture and a food source
to grow. The best way to reduce and
prevent mold growth and home and in
school is to control moisture. Keep
humidity levels at home and in school
low with ventilation systems or a
dehumidifier that remove excess
moisture from the air. It is also
important to repaid leaks and remove
existing mold growth with soap and hot
water.

Assessment:

Assess students based on their performance in
the activity. Each student should have
completed a worksheet with sketches and
observations of their experiment. Use the wrap-
up questions to evaluate the student knowledge
gained in this activity.

Extensions:

1.	The mold growth experiment can be
extended for a longer growth cycle.

2.	Repeat the experiment, but cover the plates
so that students can compare mold growth in
light and dark environments.

3.	The experiment can also include the use of a
variety of foods to compare different types,.
Colors, and shapes of mold growth.

4.	Instead of using individual disposable bags
and plates, the classroom can conduct a
mold experiment using one large glass jar or
that can be tightly sealed. Please be careful
not to open the mold filled container inside
buildings. If the container is to be reused,
open it outside, away from children and
dispose of the moldy contents in the garbage
or a compost container. To thoroughly wash
the jar, use soap and hot water.

Resources and Related Links:

U.S. Environmental Protection Agency:

www.epa.gov/mold/

U.S. Environmental Protection Agency:

Learn the Issues: Air

www.epa.gov/mold/moldguide.html

www.epa.gov/mold/pdfs/moldguide.pdf

Centers for Disease Control and Prevention

www.cdc.gov/mold/


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Student Mold Growth Observation Worksheet: Name:	

Instructions:

1.	DO NOT open your experiment bag.

2.	Look at the bread and apple on the plate in your experiment bag. What do you see?

3.	Answer the observation questions to record your data and then draw a picture of what
you see in the space provided beneath the questions.

Day	Data and Observations: Is mold growing?	What is mold growing on?	

What color is the mold?	Describe the texture of the mold (fuzzy, smooth, lumpy):

Draw a picture of your experiment: What do you see?

Day	Data and Observations: Is mold growing?	What is mold growing on?	

What color is the mold?	Describe the texture of the mold (fuzzy, smooth, lumpy):

Draw a picture of your experiment: What do you see?

Day	Data and Observations: Is mold growing?	What is mold growing on?	

What color is the mold?	Describe the texture of the mold (fuzzy, smooth, lumpy):

Draw a picture of your experiment: What do you see?

SEPA




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Name:

Day	Data and Observations: Is mold growing?	What is mold growing on?	

What color is the mold?	Describe the texture of the mold (fuzzy, smooth, lumpy):

Draw a picture of your experiment: What do you see?

Day	Data and Observations: Is mold growing?	What is mold growing on?	

What color is the mold?	Describe the texture of the mold (fuzzy, smooth, lumpy):

Draw a picture of your experiment: What do you see?

Day	Data and Observations: Is mold growing?	What is mold growing on?	

What color is the mold?	Describe the texture of the mold (fuzzy, smooth, lumpy):

Draw a picture of your experiment: What do you see?

Day	Data and Observations: Is mold growing?	What is mold growing on?	

What color is the mold?	Describe the texture of the mold (fuzzy, smooth, lumpy):

Draw a picture of your experiment: What do you see?

oEPA


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Name:

Day	Data and Observations: Is mold growing?	What is mold growing on?	

What color is the mold?	Describe the texture of the mold (fuzzy, smooth, lumpy):

Draw a picture of your experiment: What do you see?

Day	Data and Observations: Is mold growing?	What is mold growing on?	

What color is the mold?	Describe the texture of the mold (fuzzy, smooth, lumpy):

Draw a picture of your experiment: What do you see?

Day	Data and Observations: Is mold growing?	What is mold growing on?	

What color is the mold?	Describe the texture of the mold (fuzzy, smooth, lumpy):

Draw a picture of your experiment: What do you see?

Final Observations:

What changes did you observe from start to finish?	

What happened to the bread and apple in your bag?	

How can you use this new knowledge to help prevent mold growth at home or in school?

What does mold need to grow?

&EPA

iJLd


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