Science Fenns K-5Grades K to 5
A toy car at the top of a cardboard ramp propped on books, with a ruler laid along the floor.

Science / All lessons / Forces and Motion

Test a Force

Plan an experiment with a car and a ramp.

Lesson 16 of 41

Try this first

Before we start

Today’s story

Test a Force

Cars roll faster down a steep hill than a gentle one. That is a guess. A fair test can turn it into knowledge.

To plan the test, ask a question. Pick one thing to change. Keep everything else the same. Pick how you will measure.

Today you plan and run a ramp test. A toy car and a board are enough. Here are the steps.

See it

Five steps. Every time.

    Hands on

    Ramp and Car

    30 minutes · Do this with a grown-up nearby

    You need

    • Toy car
    • Flat board
    • Books
    • Tape measure
    • Pencil
    • Paper

    Do this

    1. Prop the board on one book to make a ramp.
    2. Release the car at the top without pushing.
    3. Measure how far it rolls on the floor.
    4. Repeat three times.
    5. Add a second book and repeat.
    6. Add a third book and repeat, then find averages.
    Write or draw: A table with the number of books, three distances and the average.

    Watch for: Did a taller ramp mean a longer roll? Was the pattern steady?

    Safety: Keep your feet out of the car's path.

    Same every time

    Three rules

    Rule 1Change one thing

    Fair tests change only one thing.

    Rule 2Measure the same way

    Start from the same spot every time.

    Rule 3Repeat

    Three trials beat one.

    Grandpa Fenn’s notebook

    Say it like a scientist

    variable
    A thing in a test that can change.
    trial
    One run of a test.
    average
    The sum divided by the number of trials.
    force
    A push or a pull.

    Poppy’s quiz

    Six questions

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

    Talk about it

    Say it out loud

    • What evidence from your three trials shows that ramp height mattered?
    • Where have you seen a ramp or hill used at home, like loading a truck?
    Did you know

    Friction on the floor slowly takes energy from a rolling car until it stops.

    Someone who does this

    A transportation engineer tests road slopes so vehicles can stop safely.

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