Bell in a vacuum

Inside a closed glass jar by the gradual depletion of air, ringer sound fades, and finally die down.

On the plastic base, a bell pump is placed. Under this bell, an electric ringer is placed. Sound is the vibration of air or other media. In a vacuum, sound vibration does not travel, because there is nothing that can oscillate. 

Material: glass, plastic, wood

Power supply: 220 V

Dimensions (cm): 60 x 40 x 40