Identifier:
M: WM&S - 014
Concept Overview
Sound requires a medium for its transmission
Lecturer Procedure
| Steps to Follow | Expected Result |
|---|---|
| Flip the switch to start the bell ringing. | Bell should be heard clearly by all students. |
| Turn on vacuum pump. | Sound created by bell will decrease in volume. |
| Turn off vacuum pump. | Bell can be seen ringing, but sound cannot be heard (or can barely be heard). |
| Allow air into the system as rapidly as possible. | The increasing sound is rapidly heard, usually to the back of the room. |
Historical References; Taken from original work of Percy H. Carr, 1970
“There have been papers published stating that the lack of transmission is not due to lack of medium, but to impedance mismatch between the bell and medium. However, after I have read the arguments, I feel that they are saying 'no medium' in different words.”
Tutorial:
Set-up Instructions for M: WM&S - 14