Science Fenns K-5Grades K to 5
A boy rolling a ball slowly and quickly toward a row of paper cups on a gym floor.

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Faster Means More Energy

How an object’s speed changes what it can do.

Lesson 21 of 41

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Before we start

Today’s story

Faster Means More Energy

Tomas sets up ten paper cups in a line. He rolls a ball slowly and it only tips one. He rolls it hard. It sends cups flying.

The faster ball hit harder. It did more. A rolling ball carries energy of motion. When speed goes up, so does that energy.

This is why a fast truck is harder to stop than a slow one. The steps show how to test it.

See it

Five steps. Every time.

    Hands on

    Cup crash

    25 minutes · Do this with a grown-up nearby

    You need

    • A ball
    • Ten paper cups
    • A smooth floor
    • Tape
    • Paper and pencil

    Do this

    1. Set cups in a row at the same spot.
    2. Mark a start line with tape.
    3. Roll the ball slowly.
    4. Count cups knocked over.
    5. Roll it at medium speed and count.
    6. Roll it fast and count.
    7. Make a table and repeat twice.
    Write or draw: A table with speed and cups moved.

    Watch for: Notice that faster rolls knock over more cups.

    Safety: Roll on the floor, not at people. Clean up cups and balls.

    Same every time

    Three rules

    Rule 1Faster means more energy.

    The object can do more.

    Rule 2Test with the same ball.

    Change only the speed.

    Rule 3Count the result.

    A number shows the pattern.

    Grandpa Fenn’s notebook

    Say it like a scientist

    speed
    How fast something moves.
    mechanical energy
    The energy of moving things.
    compare
    To look at how things are alike or different.

    Poppy’s quiz

    Six questions

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

    Talk about it

    Say it out loud

    • What pattern did you see between speed and cups moved? How do you know?
    • When have you seen something fast do more than something slow, like a hailstone or a ball?
    Did you know

    A speed limit sign is a reminder that faster cars have more energy and need more space to stop.

    Someone who does this

    A traffic engineer sets speed limits to keep people safe.

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