Friction & Surfaces · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Friction: why rough surfaces slow things down

Science · Forces & Motion · ages 7-8
Name ______________________   Date ____________

  1. Rough surfaces make more friction than smooth surfaces.

    Circle one:   True   False

  2. Which of these surfaces is smooth?

    • Sand
    • Gravel
    • Glass

  3. Friction can slow a moving thing so much that it stops.

    Circle one:   True   False

  4. What is the force called when two surfaces rub together and slow things down?

    • Gravity
    • Friction
    • Motion

  5. Look at the chart. On which surface did the toy car roll the shortest distance?

    Carpet2Wood floor5Ice8
    • Carpet
    • Wood floor
    • Ice

  6. The chart shows how far a toy train rolled on gravel and on a wood floor. How many more steps did it roll on the wood floor?

    Gravel2Wood floor7

    Answer: ______________

  7. A sled is sliding too fast and needs to stop soon. On which surface will it stop soonest?

    • Smooth ice
    • A tile floor
    • A gravel path

  8. The chart shows how far the toy car rolled on carpet and on ice. How many more steps did it roll on ice than on carpet?

    Carpet2Ice8

    Answer: ______________

  9. In winter, people spread sand on icy paths. Why does that help people walk without slipping?

    • Sand is soft, so it feels nicer under shoes
    • Sand is rough, so it adds friction and shoes grip the path
    • Sand makes the ice smoother and faster

  10. Zara says, "Friction only happens on rough surfaces. Smooth ice makes no friction at all." What is wrong with her idea?

    • Zara is right, smooth ice makes no friction
    • Ice is smooth, but it still makes some friction
    • Ice makes more friction than rough gravel
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Friction: why rough surfaces slow things down W1-mt_-p_xp4hMvh-s1

  1. True · Bumpy, rough surfaces catch and slow things down more than smooth ones do.
  2. Glass · Glass is smooth. Sand and gravel are rough and bumpy.
  3. True · Friction slows movement down, and with enough rubbing the moving thing stops completely.
  4. Friction · That rubbing force is called friction.
  5. Carpet · The car only rolled 2 steps on the rough carpet. Rough surfaces create the most friction, so the car stops sooner.
  6. 5 · 7 steps on the wood floor minus 2 steps on gravel equals 5 more steps.
  7. A gravel path · Gravel is the roughest, so it makes the most friction and stops the sled soonest.
  8. 6 · 8 steps on ice minus 2 steps on carpet equals 6 more steps.
  9. Sand is rough, so it adds friction and shoes grip the path · Rough sand on smooth ice makes more friction, so shoes grip instead of sliding.
  10. Ice is smooth, but it still makes some friction · Every surface makes some friction. Smooth ice just makes less than rough surfaces do.
Worksheet · LightMySky