Objective 1: To experiments how to change a friction force.
Objective 2: To develop with the student an experiment in order to compare several test of friction forces, and the effect of changing parameters.
From all the concepts we have discuss up to now, friction is the most approachable in terms of intuition, at least in terms of slowing down a movement. This session will be dedicated to experimenting how to slow down a movement generating a frictional force.
45 minutes
Look with your students at these two pictures and ask them why cyclists and speed skiers have those special equipments. Also ask them to look at the position they take and discuss it.
Give to your students in groups of 3, one ramp and one car. Ask them first to check the distance the car reach if they release it on the slope.
The challenge consists to transform the car to reduce as much as possible the displacement of the car without touching the wheel system, and without changing too much its weight
Students have performed experiments, where they could only compare their own tests because they have all vary the parameters in several ways. Propose them for the next session to organise a contest but fixing parameters.
Discuss with them what are the parameters that have to be fixed, and which ones they will vary to study the impact of the friction force.
By adding area that resists to the air, the car is slowed down in its movement, and its displacement is reduced.