PIRA Classification: 2B30.30
Description: The hemispheres are actually discs with a small empty volume between them. The hemispheres are sealed with an O-ring and are evacuated with a pump or by sucking on the hose (more dramatic). When the system is evacuated, the hemispheres cannot be separated. An additional demo would be to place the hemispheres in a bell jar and evacuate that. The hemispheres should fall apart.
Special Instructions: Make sure the valve is closed while still pumping on the hemispheres.
Condition: OK
Setup time: 2 minutes
Safety Issues: None