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Bell in a Jar: Sound in a Vacuum

A bell is contained within an air tight jar.

Concept Overview:

1. Sound requires a medium for its transmission

Lecturer Procedure

Step(s) to FollowExpected Result
1. Flip the switch to start the bell ringing.Bell should be heard clearly by all students.
1. Turn on vacuum pump.Sound created by bell will decrease in volume.
1. Turn off vacuum pump.Bell can be seen ringing, but sound cannot be heard (or can barely be heard)
1. Allow air into the system as rapidly as possibleThe increasing sound is rapidly heard, usually to the back of the room

 

Identifier
M: WM&S - 014