3B55.10 - Interference of Sound Waves - Rotating Platform, LED

Code Number:
Demo Title:
Interference of Sound Waves - Rotating Platform, LED
Constructive & Destructive Interference of Sound Waves
Area of Study:
2 large speakers, amplifier, wave generator, and LED mounted with Microphone.

Mount the two speakers on a moveable table so that the tweeters are 1 meter apart.  The wave generator should be run at 1000 Hertz or more.  LR 70 works best for this as it is a square room and therefore easy to set up a standing wave pattern.  When the pattern is produced the students should be able to move their heads from side to side and detect the standing wave pattern.

The LED mounted with the microphone is so that you can show where the nodal points are in a room, (The LED will light at the peaks and go out at the nodes).

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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.