It's a Breeze - How Air Pressure Affects You

Results from Air Pressure Experiments

Experiment #1

Your chest expands because, like blowing up a balloon, you are increasing the number of air molecules inside your lungs. This causes your lungs to expand in order to provide space for the increased number of air molecules.

Experiment #2

When a balloon is blown up, the air pressure inside the balloon slowly becomes greater than the air pressure outside the balloon. Since the balloon is made of rubber and is expandable, it grows larger and larger. When the balloon is popped, the air escapes instantly. The sound you hear is from the molecules of air inside the balloon coming into sudden contact with the molecules of air outside the balloon.

Experiment #3

The milk jug will crumple in on itself. When you added the hot water, it caused the air temperature inside the jug to rise. While the container was sealed no air could get into or out of the jug. When the water inside the jug cooled, the air cooled and caused the pressure inside the jug to decrease.

As the pressure on the inside walls of the jug decreased, the walls of the jug collapsed. Since there wasn't enough air pressure inside the jug to offset the air pressure on the outside of the jug!

Updated: January 22, 2003

Click here to do the experiments, or find out more about air pressure.