Don't scoff at air pressure
This
activity has to be done by an adult only. You will need a wide-mouth
bowl, empty soda can, water, 2 or 3 ice cubes and tongs.
1. Add 3-4 spoonfuls of water to an empty soda can and start heating the soda can.
2.
While you wait for the water to start boiling, fill a bowl with about
1/2 inch of cold water (add a few ice cubes) and keep it close to
the
stove.
3. Let the water boil for a minute or so. Let the steam come out steadily for a while.
4. Hold the can with the tongs and quickly turn it over and place into the bowl of cold water.
5. It takes just a split second. With a loud sound, the can will crumple.
Explanation:
When water is the can is boiled, the steam starts replacing the air
inside the can. Soon the can is filled with just steam. When it
is cooled, the vapor becomes water drops again. Since water
turning to steam expands nearly 1600 times, the change from vapor to
water leaves a near vacuum condition inside the can. The air pressure
outside and near vacuum inside is too much for the thin aluminium can
to handle.
In case it didn't work properly, repeat but this
time make sure (1) you let it boil long enough, (2) you moved the can from the stove
to the cold water quickly and (3) you turned the can upside down so that the
open end of the can is in the water (not letting steam escape).
Previous air pressure activity
Back to air pressure chapter
Back to main table of contents