TOPIC:

ID Code: C5-18
Purpose: Demonstrate Newton's third law of motion
Description: With the sail unmounted, turn on the fan and release the cart; it moves in the direction opposite to that of the blowing air. Mount the sail and blow into it with your breath or with a fan; it moves in the direction which you are blowing. Finally, with the sail in place turn on the fan while holding the cart. Notice the flexing of the sail.
Availability: Available

See the Physics Question of the Week for 3/2/2015 for an example of how this demonstration can be used in class interaction and discussion: lecdem.physics.umd.edu/question-of-the-week-archive.html

Note that this fairly silly-looking cart is a good model for a popular type of watercraft: en.wikipedia.org/wiki/Airboat , so this is a question with application to real life!

When using this device, not that the battery is connected via an alligator clip - when not in use, clip it to the frame for safety. Watch your fingers around the fan blade!