College of Liberal Arts & Sciences
2C60.10 - Fluidizing Bed
Connect the air hose to the compressed air and the connection on the plastic container. Turn on just enough air to see some geysers appear in the beads. A buried ping pong ball will rise when the air is turned on, and a steel ball bearing will sink. A golf ball is almost neutrally buoyant and will sink half way into the beads but still be visible. A toy boat will be able to "sail" in the beads just as it can in the water.
Video Credit: Daniel Reinart.
- Eric Bertin, "Statistical Physics of Frictional Grains: Some Simple Applications of the Edwards Statistics", AJP, Vol. 92, #5, May 2024, p. 375.
- D. A. May and J. J. Monaghan, "Can a Single Bubble Sink a Ship?", AJP, Vol. 71, #9, Sept. 2003, p. 842.
- Bruce Denardo, Leonard Pringle, Carl DeGrace, and Michael McGuire, "When Do Bubbles Cause a Floating Body to Sink?", AJP, Vol. 69, #10, Oct. 2001, p. 1064.
- George Spagna, "Buoyant Force Analog: A Demonstration for the Vertical Stage Overhead Projector", AJP, Vol. 49, #5, May 1981, p. 507.
- Alex Lopatka, "Flows of Volcanic Rock and Gas Ride a Carpet of Air", Physics Today, Vol. 72, #6, June 2019, p. 19.
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.