A traditional demonstration apparatus brought up to date. The apparatus consists of 2 plastic hemispheres with an effective O-ring seal and a 6mm plastic valve. When evacuated of air, a force in excess of 1400N is required to separate them. The Spheres can be evacuated with a Hand Operated Pump.

Learning Outcomes

• Key Stage 3 Chemistry - The particulate nature of Matter: The properties of the different states of matter (solid, liquid and gas) in terms of the particle model, including gas pressure.
• Key Stage 4 Physics - The Structure of Matter: Links between pressure and temperature of a gas at constant volume, related to the motion of its particles (qualitative).  Explain why the work done in the compression or expansion of gases is the product of the pressure and the change in volume.