College of Liberal Arts & Sciences
5B20.35 - Faraday's Cage - Radio
Code Number:
References:
5B20.35
Demo Title:
Faraday's Cage - Radio
Condition:
Good
Principle:
Electrostatics
Area of Study:
Electricity & Magnetism
Equipment:
Cell Phone and Aluminum Foil, Faraday's Cage, and Transistor Radio.
Procedure:
Cell phones are miniture radio transmitters/receivers. Have someone call your cell phone in class and see that the phone will ring. Wrap the phone in aluminum foil and repeat the experiment. The phone does not receive the signal and therefore does not ring. NOTE: If the aluminum foil touches the phone it will act like an antenna extension and receive the call. Put the phone into a plastic or insulated bag before wrapping with aluminum foil.
Put the radio in the Faraday's cage. When the radio is placed inside the Faraday's cage it will be unable to receive radio signals.
NOTE: Grounding the base of the cage may help improve the radio demo.
- Zhu E-qing, "Electromagnetic Shielding", TPT, Vol. 27, #9, Dec. 1989, p. 686.
- Edward J. Carlone and Hugh D. Young, "Radio and TV Reception", TPT, Vol. 22, #3, Mar. 1984, p. 180.
- Borislaw Bilash II and David Maiullo, "Keep It Out of the Cage", A Demo a Day: A Year of Physics Demonstrations, p. 248.
- Jearl Walker, "5.3. Lightning: Vehicles", The Flying Circus of Physics Ed. 2, p. 220.
- Robert Ehrlich, "O.6. Shielding a Radio", Turning the World Inside Out and 174 Other Simple Physics Demonstrations, p. 174 - 175.
- Brian Jones and Matt Fackelman, "Radio Shack - Stopping Electromagnetic Waves", Don't Forget the Duct Tape! - The How and Why of the Experiments of the Little Shop of Physics - A Work in Progress, p. 97.
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.