Experiment 5 — The Ramp Race

Topic: Physics · Classes 4–5 · Pushes, pulls and friction

Aim: Send the toy past the 150 cm mark on the floor.

Daily: Friction is why your school shoes grip the floor, why cycle brakes work, and why a wet marble floor is dangerous. Oil in a machine and wheels on a suitcase are both ways of reducing it.

Question: The same block is released from the same height onto carpet and onto smooth tile. Where does it travel further?

Exp: Carpet is rough and has more friction, so the block stops sooner.

Question: Friction is a force that…

Exp: It always acts against the direction of sliding.

Question: Wheels help because rolling has…

Exp: Rolling friction is much smaller than sliding friction.

Question: Which is a USEFUL result of friction?

Exp: Without friction, walking, writing and braking would be impossible.

Question: Oil is put in machines to…

Exp: A film of oil keeps the surfaces apart so they rub less.