Previous Next

Bell in a Vacuum
# 3B30.30

Description: A remote controlled electronic bell is placed in a vacuum container. Play the bell in a partial vacuum and without the vacuum to hear the change in sound intensity.

Instructions: Place the remote controlled electronic bell on top of a provided piece of foam rubber in the vacuum jar. The foam rubber helps to isolate vibrations from the bell. Switch on the vacuum pump and allow it to draw a vacuum for about a minute. Switch off the pump, which is noisy, and push the remote control to play the bell. If there is a valve next to the vacuum jar, open the valve to allow air into the jar. If there isn't a valve, just pull the vacuum hose off of the jar. You will hear the sound intensity increase as air enters the jar. Note that the electronic bell will only play continuously for about 15 or 20 seconds, so don't wait too long to open the valve (or pull the vacuum hose) after starting the bell.

Parts: Vacuum jar; Vacuum hose (make sure it is a tight connection to the pump and the jar); Vacuum pump; Remote controlled electronic bell and remote button; Foam rubber to place the bell on; Extension cord

Purchased/Built: purchased

Setup Time: 5 min

Quant. in Demo Room: 1

Demo References
Hilton S-3a Air is pumped from a bell jar as a battery powered bell rings inside.
The Video Encyclopedia of Physics Demonstrations Disc 10-09 Place an electronic siren with a LED in series in a bell jar.
Sutton S-52 Ring a bell in an evacuated bell jar. Other methods and hints.
Sutton S-53 You can hear a bell in a closed jar while air is present.
Freier and Anderson Sh-2 A doorbell is placed in a bell jar which is then evacuated.

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