A closer look at gases

When you blow up a balloon, you fill it with air particles moving at speed. The particles knock against the sides of the balloon and exert pressure on it. The pressure is what keeps the balloon inflated. In the same way, all gases exert pressure. The pressure depends on the temperature of the gas and the volume it fills, as you will see below. 

The particles in this gas are moving at speed. They knock against the walls of the container and exert pressure on them. 

The particles take in heat energy and move even faster. They strike the walls more often and with more force. So the gas pressure increases. 

If the volume of a gas is constant, its pressure increases with temperature. 

When a gas is squeezed into a smaller volume, its pressure increases. 

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