Science Fenns K-5Grades K to 5
A child tilts a ramp of cardboard with a toy car at the top and a magnet at the bottom, with a ruler and a chart.

Science / All lessons / Gravity, Friction and Magnets

Forces Together

Plan an investigation that uses two forces at once.

Lesson 16 of 40

Try this first

Before we start

Today’s story

Forces Together

Kayla rolls a toy car down a board and it speeds up. Gravity is pulling it. The floor slows it. That is friction. A friend tapes a magnet at the end. Now the steel car feels a third pull from the magnet.

Real life uses many forces at once. Gravity pulls down. Friction fights sliding. A magnet pulls at a distance. We can plan a test to see how they work together. We change one force and keep the others steady.

That is a fair test with more than one force. It takes a clear question, a plan and careful records. Here are the steps.

See it

Five steps. Every time.

    Hands on

    Ramp and Magnet Plan

    30 minutes · Do this with a grown-up nearby

    You need

    • A board for a ramp
    • Books to prop it
    • A small steel toy car or a steel nut with a card
    • A bar magnet
    • A ruler or tape measure
    • Tape
    • Notebook

    Do this

    1. Write a question about one force to change.
    2. Set the ramp at a fixed height.
    3. Roll the car with no magnet three times and measure the distance past the ramp.
    4. Place the magnet beside the track and repeat.
    5. Move the magnet farther away and repeat.
    6. Compare the averages.
    7. Write which forces you think acted.
    Write or draw: A table with Test, three distances in centimeters and the average, and a sentence naming the forces.

    Watch for: Notice that the magnet changed how far the car went. Notice if the change was big when the magnet was far.

    Safety: Keep fingers clear of the ramp and magnets away from phones.

    Same every time

    Three rules

    Rule 1Name each force.

    Know what is pulling and what is resisting.

    Rule 2Change one at a time.

    That keeps it fair.

    Rule 3Record every trial.

    Data tells you if the plan worked.

    Grandpa Fenn’s notebook

    Say it like a scientist

    force
    A push or a pull that can change how something moves.
    investigation
    A plan to answer a question by testing.
    variable
    The one thing you change on purpose in a test.
    friction
    A force that works against sliding.

    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 which force changed the result?
    • When have you used more than one force at home, like pushing a wagon uphill?
    Did you know

    Some roller coasters use magnets to slow the train smoothly, with no rubbing at all.

    Someone who does this

    A toy designer tests ramps and magnets to make toys that roll and stick the way kids expect.

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