Spring-Apart Air Track Gliders, 1N20.20

Topic and Concept:

• [:Linear_Momentum#ConservationOfLinearMomentum:1N20. Linear Momentum, Conservation of Linear Momentum]

Location:

• Floor Item: ME, South Wall attachment: mainPhoto

Abstract:

Using a scissors, cut a string holding a compressed spring between two air gliders initially at rest.

Important Setup Notes:

• This demonstration requires a supply of compressed air, permanent supplies located in rooms 2103, 2223, 2241.

Setup and Procedure:

1. Place air track on lecture bench, and connect the compressed air supply from the lower white panel of the [:RedWhiteGasCart:Red & White Gas Cart] to the track using an air hose.

2. Place two gliders on the track, approximately centered.
3. Turn on the air supply by opening the valve located on the lower white panel of the cart.
4. If the gliders seem to slide in one direction, this is most likely due to the track being unlevel. Adjust the set screws until this no longer occurs. It is a good idea to do this ahead of time.
5. Using a small section of string, make a tied loop, and hang it of a hanger on each glider so that the two gliders are connected.
6. Carefully compress the spring into a U shape, and place it between the two gliders.
7. When ready, cut the string with the scissors to release the potential energy.

Cautions, Warnings, or Safety Concerns:

• Make sure you are using compressed air (white panel) and NOT methane gas (red panel) which is extremely flammable!
• The spring can sometimes fly off toward the demonstrator's face. Either wear safety glasses or look away during cutting.

Discussion:

Discuss the physics behind the demonstration, explaining some of the various steps of the demonstration when appropriate.

Videos:

• [https://www.youtube.com/user/LectureDemostrations/videos?view=1 Lecture Demonstration's Youtube Channel]

References:

• [http://www.grc.nasa.gov/WWW/k-12/airplane/conmo.html Conservation of Momentum - NASA]

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