PURPOSE: To illustrate weightlessness in free fall.

DESCRIPTION: The keeper is placed on an aluminum shelf about two centimeters below the "C" magnet; the gravitational force on the keeper is sufficient to keep it from being attracted to the magnet. When the system is released and allowed to fall with the acceleration of gravity, the keeper becomes weightless and is attracted to the magnet. Click your mouse on the photograph at the left above to see the keeper released by itself (also available in slow-motion.) Clicking the center photograph (or the slow-motion version) shows the entire system in free-fall. Note the click as the keeper hits the magnet immediately when it is dropped. The rightmost image and video show another version of the same demonstration.

SUGGESTIONS: See Question of the Week #107 for information on using this demonstration to enhance class involvement.

REFERENCES: (PIRA unknown.)

EQUIPMENT: Two magnet/keeper/plastic shelf systems, as photographed.

SETUP TIME: None.