3Fall-3

Outcomes

• Pupils can talk about what forces act during free fall
• Pupils can explain why objects accelerate in a gravitational field

Specification References

1.16 describe the forces acting on falling objects and explain why falling objects reach a terminal velocity

Starter

Measuring g by freefall - use the g by freefall kit to measure g

Main Body of Lesson

1)Falling milk bottle with holes in: Fill a milk bottle with water. Show how water comes out of the holes. To stop the water put the lid on and cover the hole in the lid. The higher you can drop it from the more dramatic the effect. Then drop it and show how the water no longer comes out of the holes as the water is falling at the same rate as the milk bottle.

2)Falling force meter: using a PASCO force meter attach a 1kg mass to the force meter and show that it reads 10N (a nice place to recap the wieght equation etc.). Then drop the force meter onto a cushion or sandbag a notice that the force meter reads 0N on the way down as the force meter is falling at the same rate as the mass. Use strig to avoid the PASCO meter hitting the floor. Set up a graph and a dial on screen.

For ech example have pupils try to explain to each other what is going on. This should lead onto discussing the concept of freefall and apparent weightlessness and actual weightlessness (can talk about the Vomit Comet if you like).

Pupils ot make some notes on falling, acceleration due to gravity and weightlessness

Additional Information

Resources Required

g by freefall apparatus

Milk bottle demo:

• An old 1 pint milk bottle with 4 holes at the bottom and a lid with a hole in it too.
• A bucket on the floor and a mop to hand

Falling PASCO sensors

• A length of string to catch the PASCO force meter when dropped - should be long enough that the 1kg mass hits the ground whilst the forcemeter does not
• To help this the mass could also be on a short piece of string too

A landing zone of some description would be good too (e.g. packing peanuts or foam)