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Where do fallen leaves go?

Where do fallen leaves go?
Lesson narration:
English Spanish
Scroll for prep
Video trouble?
Slide Image
DISCUSS:
Where do you think the dead leaves that fall in the forest go?
What could you do to find out?
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Step
01/20
You’ll work with a partner.
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Step
02/20
Get your supplies.
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Step
03/20
Cut out your Suspect Cards and Leaves along the dotted lines.
Put your Suspect Cards in a pile to the side.
Put your Leaves on your Leaf Pile sheet.
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Step
04/20
Lay out Evidence Board sheets in front of you. Put the sheet with
the “Suspect 1” box on top of the sheet with the stripes. Overlap the
stripes so that the Suspect boxes on the two sheets line up.
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Step
05/20
Place the Red Fox card in the “Suspect 1” box on your Evidence
Board. Read it with your partner. Underline what happened to the
leaves. Circle who else was near the leaves.
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Step
06/20
When the timer starts, rip your leaves in half. Rip as many as you can
until the timer stops. Make sure all of your leaf pieces are on your
Leaf Pile sheet.
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Step
07/20
Put the Mouse card in the “Suspect 2” box on your Evidence Board.
Read the card with your partner. Underline what happened to the
leaves. Circle who else was near the leaves.
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Step
08/20
When the timer starts, rip your leaf pieces in half. Rip as many as you
can until the timer stops.
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Step
09/20
Put the Worm card in the “Suspect 3” box on your Evidence Board.
Read the card with your partner. Underline what happened to the
leaves. Circle who else was near the leaves.
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Step
10/20
Put some leaf pieces on top of the Worm card. Then, when the timer
starts, rip your leaf pieces in half. Rip as many as you can until the
timer stops.
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Step
11/20
Pour water on your leaf pile and watch what happens. Or go to the
next slide.
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Step
12/20
Discuss:
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Step
13/20
Draw rain clouds in the box above your leaf pile with your blue crayon
to help you remember that your leaf pieces are now wet.
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Step
14/20
Put the Fungi card in the “Suspect 4” box on your Evidence Board.
Read the card with your partner. Underline what happened to the
leaves. Circle who else was near the leaves.
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Step
15/20
Take some of your leaf pieces and put them on top of your Fungi
card. When the timer starts, rip your leaf pieces in half.
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Step
16/20
Put the Bacteria card in the “Suspect 5” box on your Evidence Board.
Read the card with your partner. Underline what happened to the
leaves.
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Step
17/20
Take most of your leaf pieces and put them on top of the Bacteria
Suspect Card. When the timer starts, rip your remaining leaf pieces
in half.
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Step
18/20
Get the rest of your supplies.
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Step
19/20
Discuss. Then, answer question 1 on your Solve the Case worksheet.
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Step
20/20
Discuss. Then, answer question 2 on your Solve the Case worksheet.
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Slide Image
DISCUSS:
What do you see happening in real life that matches your model?
What's different?
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DISCUSS:
What kinds of dead stuff or leftover waste from these living things could be food for decomposers?
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Slide Image
Slide Image

organism


1 of 14

any living thing
Slide Image

environment


2 of 14

a living thing’s surroundings, including other living things and non-living parts like soil, water, and air
Slide Image

soil


3 of 14

covers the Earth's surface; made of tiny rocks and material from dead plants and animals

matter


4 of 14

anything that takes up space and has weight; can be in different forms such as solid, liquid, or gas
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Slide Image

model


5 of 14

a pretend version of something that scientists use when the real thing is too big, small, or complicated to work with
Slide Image

evidence


6 of 14

Information that can be used to support or reject an idea
Slide Image

decomposer


7 of 14

a living thing that can break down dead organisms or animal waste

decompose


8 of 14

the process of breaking down dead organisms or animal waste
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Slide Image

compost


9 of 14

decayed plant material that can be used as fertilizer
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fungus (fungi)


10 of 14

a living thing that is a decomposer, such as a mold or mushroom
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mushroom


11 of 14

a type of fungus that usually has a stalk and cap
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mold


12 of 14

a type of fungus that often decomposes food
Slide Image

microscope


13 of 14

a tool used to see very tiny things up close
Slide Image

bacteria


14 of 14

an organism that is usually a decomposer; some cause illness
Lesson narration:
English Spanish

Lesson details

Grade 5

Ecosystems & The Food Web

Decomposers & Matter Flow

5-LS2-1

Activity Prep

Print Prep
THIS LESSON WAS REVISED ON JUNE 14, 2025. Here is a link to the previous version.
In this lesson, students develop a model to describe the flow of matter between living things and the environment, with an emphasis on decomposers. In the activity, Decomposer Detectives, students gather information from suspects on the forest floor, and model the decomposition process of fallen leaves in order to solve the mystery of why those leaf piles seem to disappear.
Preview activity

I have a Mystery Pack

Evidence Board worksheet 1 per pair
Leaves & Leaf Pile worksheet 1 per pair
Solve the Case worksheet 1 per pair
Suspect Cards worksheet 1 per pair
Crayons
Any shade of blue. Markers or colored pencils will also work.
Details
1 crayon per pair
Scissors
1 pair per student
Clear Plastic Cups (10 oz)
1 cup per class
Plastic Plates (10")
1 plate per class
Prep Instructions

We suggest students work in groups of pairs. You will need access to water for this activity.

Prep Your Solve the Case worksheets Cut each of these worksheets in half so that each student has a 1/2 sheet.

Jump to

Exploration

10 mins

Hands-On Activity

30 mins

Wrap-Up

15 mins

Lesson details

Grade 5

Ecosystems & The Food Web

Decomposers & Matter Flow

5-LS2-1

Extend this lesson

Vocabulary

Vocabulary

Student slideshow: English | Spanish

Teacher printout: English & Spanish

Unit Reading

Unit Reading

What Can Young People Do to Protect the Environment?

In this reading, students learn simple steps they can take to help protect the environment.

Mini-lessons

Mini-lessons

You can elaborate student learning and engagement with Mystery Science mini-lessons.

If you are in an NGSS state, these mini-lessons support the DCI LS2.A: Interdependent Relationships in Ecosystems

Transcripts

Credits
 
Ecosystems Lesson 3: Where do fallen leaves go?

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