Friction
👩🏫 Teacher’s Guide
Objective
Describe friction as a force that resists motion between surfaces and explain effects of rough vs. smooth surfaces.
Vocabulary
- — A force that resists motion
- — Outside layer in contact
- — Bumpy; more friction
- — Even; less friction
- — Opposition to movement
Teaching Notes
Contrast car on carpet vs. tile. Emphasize that friction can be helpful (stopping, gripping).
Answer Key
More friction on rough surfaces, less on smooth; friction slows motion.
Extension Ideas
Test shoe tread patterns for stopping distance on different floors.
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🧒 Student Worksheet
Concept and Helping Material
Friction is the force that slows things down when two surfaces rub. Rough surfaces make more friction. Smooth surfaces make less friction.
Words to Learn
- Ice has ___ friction.
- Sandpaper has ___ friction.
- Brakes use friction to help us ___.
- Shoes with tread help us not ___.
Sentences to Fill In
- The car went farther on foil because friction was ___ (low / high).
- On carpet the car stopped sooner because friction was ___ (low / high).
- Friction can be ___ (helpful / never useful).
- We need friction to ___ (stop / float).
- Smooth surfaces have ___ (less / more) resistance.
Hands-On Experiment — Ramp Races
What You Need
toy car, 3 ramps, foil, sandpaper, towel, tape, ruler
What You Do
Cover ramps with different materials; release car from the same height; measure distance traveled; compare.
Reflection
- Which surface produced the least friction? How do you know? (Answer may vary.)
- Why do winter boots have deep treads? (Answer may vary.)