Theory: The average speed of molecules in a gas increases with temperature. Also, at constant pressure, volume expands as temperature is increased. This model illustrates both of those principles.
Description: The rotation speed of the base of the apparatus is controlled by a knob. This is analogous to temperature. Increasing the speed gives more energy to the balls ("molecules") in the apparatus, which increases the pressure, which results in an expansion of the chamber containing the balls. To get good results the masses that are added to the counter-balance must be carefully chosen.
Setup time: 10 minutes.
References: (available in the demo room)