Previous Next

Ames Tube
# 3B70.101

Description: Use the Ames Tube and two associated tuning forks to show sympathetic vibrations, beats and mechanical coupling.

The Tuned Cavity - By holding the ames tube by the prong end and effectively clamping the prong, then activating the 880 Hz fork and placing it at the mouth of the half-wave end of the ames tube, it is possible to demonstrate that the tube itself is a half-wave open pipe trimmed to 880 Hz. The fork end of the ames tube can also be activated and the pipe detuned by closing the half-wave pipe mouth effectively demonstrating that the unit is non-functional as a closed pipe.

Sympathetic Vibration - By holding the ames tube so that the fork is free to vibrate and placing the activated 880 Hz fork at the open end of the tube, the forked end of the tube will sympathize with the 880 Hz fork. Duplicating the experiment with the 883 Hz fork, it will be noted that the fork portion of the ames tube will not sympathize even though the half-wave portion will amplify the 883 Hz frequency.

Beat Phenomena - By striking the ames tube and setting it into resonance at 880 Hz, plus striking the 883 Hz fork and setting it into vibration, then placing the vibrating 883 Hz fork at the mouth of the ames tube the 3 Hz/sec hetrodyne can be heard.

Mechanical Coupling - By striking the 880 Hz fork, then placing the handle end into mechanical contact with the ames tube as shown in the photograph, a mechanical energy transfer point is accomplished setting the ames tube into vibration.


Purchased/Built: purchased

Setup Time: 1 hour

Quant. in Demo Room: 1

Keyword Search:
complete words only, or parts of other words?

Home Manual Demo Suggestions

NCSU Physics Demonstrations
© 2010, North Carolina State University Department of Physics. The design of this site nor the
contents may be copied without the express written permission of the NC State University Department of Physics.

North Carolina State University
All Rights Reserved, 2011