You need to have JavaScript enabled to view this video clip.


Science presenter Jon Chase describes Aristotle’s and Galileo’s theories about falling bodies. With the help of some students, Jon demonstrates that two balls of similar size, but different mass, dropped from a window will land at the same time. However, a hammer and a feather dropped at the same time will not hit the ground at the same time. This is due to air resistance.

Footage from the Apollo 15 mission is shown, in which astronaut David Scott demonstrates that in the absence of air resistance, both the feather and the hammer accelerate at the same rate.
This clip is from:
First broadcast:
11 May 2012

Classroom Ideas

Ask students to predict the results of the ball-drop experiment shown in the clip, and then show them the results. Students could investigate this for themselves, working with balls of different diameters and masses, perhaps using digital cameras to record their observations.
A strong glass tube with bungs at both ends, containing a feather and a plastic marble, could be evacuated using a vacuum pump and inverted to repeat the footage seen from the Apollo 15 mission.