Science Fenns K-5Grades K to 5
A girl rubbing her hands together on a chilly morning beside a swing set and a metal slide shining in the sun.

Science / All lessons / Energy All Around

Heat and Motion

Thermal and mechanical energy at work.

Lesson 20 of 41

Try this first

Before we start

Today’s story

Heat and Motion

Kit rubs her hands together. They get warm. Her dad starts a pickup. The engine hums and moves the truck. A pot on a stove gets hot.

Heat is thermal energy. Moving things have mechanical energy. A swing in motion has mechanical energy. Rubbing turns some of that motion into heat.

Both kinds of energy are all around. The steps show you how to spot them.

See it

Five steps. Every time.

    Hands on

    Rub it warm

    15 minutes · Do this with a grown-up nearby

    You need

    • Your hands
    • A wooden block
    • Sandpaper
    • Paper and pencil

    Do this

    1. Hold your hands against your cheek. Feel the temperature.
    2. Rub your palms together fast for 20 seconds.
    3. Touch your cheek again.
    4. Rub the wood block with sandpaper for 20 seconds.
    5. Touch the block carefully.
    6. Compare.
    7. Write what changed.
    Write or draw: A sentence for each test: what moved, what got warmer.

    Watch for: Notice that more rubbing makes more warmth.

    Safety: Do not rub hard enough to hurt skin. Keep hands away from hot objects.

    Same every time

    Three rules

    Rule 1Hot things have thermal energy.

    Heat can warm other things.

    Rule 2Moving things have mechanical energy.

    They can push other things.

    Rule 3Energy can change form.

    Motion can make heat.

    Grandpa Fenn’s notebook

    Say it like a scientist

    thermal energy
    Energy of heat.
    mechanical energy
    Energy of motion and position.
    friction
    A force that happens when things rub together.

    Poppy’s quiz

    Six questions

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

    Talk about it

    Say it out loud

    • What did you feel when you rubbed your hands? How do you know it was energy?
    • Where do you see thermal and mechanical energy on a farm or at home?
    Did you know

    Rubbing two dry sticks together can make heat. People used this long ago to start fires.

    Someone who does this

    A mechanic knows that engines make both motion and heat.

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