Science Fenns K-5Grades K to 5
A fallen log in a forest floor covered in mushrooms and leaf litter, with a pecan tree above.

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Decomposers

The recyclers under the leaves.

Lesson 36 of 40

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Before we start

Today’s story

Decomposers

Under a pecan tree, leaves pile up each fall. By spring, many are gone. The ground is dark and soft.

Decomposers did that. Fungi, bacteria and some small animals break down dead plants and animals. They get energy from them.

As they work, they return matter to the soil. Plants use it to grow. Without decomposers, dead things would pile up. Follow the steps.

See it

Five steps. Every time.

    Hands on

    Rot Watch

    10 minutes now and two weeks of watching · Do this with a grown-up nearby

    You need

    • Two clear jars
    • Leaves or a banana peel
    • Soil
    • Water spray bottle
    • Lid with holes
    • Notebook

    Do this

    1. Put soil and leaves in both jars.
    2. Moisten one jar and keep the other dry.
    3. Cover with the lid.
    4. Look every two days.
    5. Draw what you see.
    6. Note fuzz and smell.
    7. Compare the two jars.
    Write or draw: A weekly drawing and notes for each jar.

    Watch for: The moist jar breaks down faster because decomposers need water.

    Safety: Do not open jars or smell mold up close. Wash hands.

    Same every time

    Three rules

    Rule 1Decomposers recycle matter.

    They keep the soil rich.

    Rule 2They need moisture and warmth.

    Cold or dry slows them.

    Rule 3They are not the enemy.

    Rot is part of life.

    Grandpa Fenn’s notebook

    Say it like a scientist

    decomposer
    A living thing that breaks down dead matter.
    fungus
    A living thing like a mushroom or mold.
    nutrient
    A needed material for growth.
    recycle
    To use again.

    Poppy’s quiz

    Six questions

    Tap an answer. Green means right. You will see why.

    Talk about it

    Say it out loud

    • How do you know decomposers were at work in your jar?
    • Where do you see leaves rotting in your yard?
    Did you know

    A teaspoon of healthy soil can hold billions of tiny living things.

    Someone who does this

    A compost manager turns waste into rich soil.

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