Vacuum Bell Jar Demonstration Set

    Product Name:  Vacuum Bell Jar Demonstration Set
    Model NO.:  PM035
For demonstration of the lack of sound transmission in a vacuum. The device consists of a plastic disk (plate) on legs, a crane, a bell of thick glass, a rubber lining and an electric bell.
Overall dimensions: 240х190х300 mm.
Weight: 1250 g
Pressure of Bell Feed: 3 volt
Complete sets of equipment include:
One plate
One base set
One bell
One packaging box
One user's manual
Use Instruction
Place the alarm (or a bell) on the extracting plate. Then add a little Vaseline on the bottom of the glass bell shade and place the shade on the plate; press a little and turn slightly the bell shade to seal the extracting plate and the bell shade. Start the alarm/bell; then extract the air from the shade. The ring sound will gradually fade out as the air in the shade becomes less and less. Vice versa, when the air is pumped into the shade gradually, the ring sound will become stronger as well.