Machined from cast iron this is an excellent replica of the traditional Magdeburg Hemisphere.
One of the hemispheres contains a mounted valve for withdrawing and sealing a vacuum.
The hemispheres are joined and the air is evacuated with the use of an air pump.
Once the air has been removed, your students will find it almost impossible to separate the hemispheres.
When the air " re-enters" inside the hemispheres then they can be separated easily.