Sound in the vacuum

This educational exhibit shows the dependancy of the travelling sound waves on the density of the medium. After the system is activated, an alarm signal can be heard from the speaker under the glass dome. A microphone mounted inside is used to examine the sound’s intensity. A vacuum pump is activated with a button and the total pressure under the dome drops. This is shown on a manometer. At the same time the sound is getting quieter, which can also be observed on the indicator connected with the microphone inside.

3rd March 2015