Year 7 Science · Unit 3 · Lesson 3
Challenge Worksheet
Learning Goals
Evaluate the claim
Someone claims…
"More friction is always better for road safety. If car tyres had maximum friction with the road at all times — the roughest possible tread, the stickiest possible rubber — then cars would stop faster and accidents would drop. Engineers should simply maximise tyre friction as much as physically possible, and road safety would improve across Australia."
(a) What part of this claim is supported by the science you have learned? Give at least one specific example of useful friction from the lesson that backs this up.
(b) What is misleading or oversimplified about this claim? Use at least two examples of harmful friction from the lesson to show why maximising friction is not always desirable.
(c) What evidence or extra information would an engineer actually need to design the safest possible tyre for Australian roads? List at least three factors they would need to consider beyond "more friction = safer".
1. At the Bathurst 1000, engineers choose between hard and soft tyre compounds for different stages of the race. Using what you know about friction, explain: (a) why soft tyres give more grip but wear out faster, and (b) why simply using soft tyres for the entire race is not the optimal strategy.
2. A student designs an experiment to test how surface roughness affects friction. They drag a wooden block across sandpaper, smooth tiles, and carpet, measuring the force needed each time. Identify one limitation of this experiment design, and explain how it could lead to an unreliable conclusion about friction.
Wrap Up
In one sentence, what was the main idea of this lesson?