A modern replacement for the Bell in a Bell Jar Apparatus. A 90mm diameter acrylic tube houses a battery-operated, high output piezo sounder. When the end plates are attached and the unit connected to a vacuum pump no sound can be heard but the sound returns when the air is allowed back in.
An effective demonstration with none of the complications of the traditional apparatus. Overall length 150mm.
Vacuum pump not included.
110 × 90mm dia.