3Fall-4
Contents
Outcomes
- Pupils can explain that drag increases with velocity
- Pupils can appreciate why objects reach terminal velocity
- Pupils can identify the factors which affect terminal velocity
Specification References
1.16 describe the forces acting on falling objects and explain why falling objects reach a terminal velocity
Starter
Guinea and Feather Demo - ask what will happen when we drop both in air. Then demonstrate the difference when both are dropped in a vacuum (using th evacuated tubes). Try to get the pupils to deduce what forces are acting. You can also show the Neil Armstrong video
OR
a)Drop a sheet of A4; falls slowly due to drag
b)Crumple it up; mass remains unchanged but falls quicker due to less drag
c)Place the A4 on a big book and drop; big book removes the effect of air resistance
d)Drop a ream of A4; all sheets fall at the same rate
Main Body of Lesson
Terminal velocity in Glycerol and Air:
1) Glycerol - demonstrate how tiny ball bearings achieve TV in glycerol. Can be made more visible with some white paper behind with unifromlly spaced lines on
2) Air - drop a parachute person with some PASCO tape on, should reach TV if dropped from high enough
Make notes on how velocity affects drag, terminal velocity and the classic skydiver example.
