Space Tube

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 evacuated using 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. Requires a vacuum pump.