1G20.30 - Leaky Cup Drop

Code Number:
Demo Title:
Leaky Cup Drop
Gravitational Acceleration
Area of Study:
Styrofoam Cup with Two Holes, Water, and Catch Basin.

Cover the two holes in the cup and fill about 3/4 full with water. Take your hands off the hole and when desired drop the cup. When the cup is in freefall no water should come out of the holes.

Warning: the cup will not survive the fall.

The swimming batons are an easier way to do this demo. Hold them under water until they are full and then put your fingers over the top two holes. When you are ready, move your fingers off the top two holes and water will stream out of the bottom two holes until the baton is dropped. The demo is easily repeated with this apparatus.

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Disclaimer: These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist.  The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose.  The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources.  Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks.  These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage.  Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.