Air Pressure - Experiment # i :
THE IMPLODING SODA CAN
Objective: To crush a soda can with air pressure.
Materials:
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Empty soda can (an Orange Crush can is particularly fitting!)
Stove or hot plate
Shallow metal pan
Tongs
Ice
Safety Precautions: Wear safety goggles. Exercise caution with boiling
water. Do not grasp soda can without tongs.
Procedure:
1. Fill an empty soda can to a depth of approximately two cm with water.
2. Place the can on a hot plate and heat the water within the can to boiling.
3. Fill a shallow pie pan with water and add ice cubes.
4. Continue heating until condensed steam rises from the can for about 1
minute.
5. Grasping the can with tongs, quickly invert the can and plunge it into the
pan of cold water. Observe.
E x p l a n a t i o n : As the soda can is heated, the air in the can is also heated,
expanding and rising out of the can. The can then fills with steam, and this steam
pushes out the rest of the air from the can. When the can is inverted into the pan
of cold water, the steam immediately condenses back into liquid water. This can
"full" of steam will condense into only a few drops of water, forming a nearly
complete vacuum within the can. Since the opening of the can is under water, air
cannot rush in to fill this vacuum. However, the outside of the can is still surrounded
by air, and air pressure pushes down with a force of 14.7 pounds per square inch
(psi). Normally, air on the inside of a can will push outward at the same pressure
and balance out this outside air pressure. However, since we have removed the air
from inside the can, and the outside air pressure is still acting on the can, the can
is instantly crushed by this outside air pressure. This experiment provides an
excellent example of the tremendous power of the air around us.
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150 Captivating Chemistry Experiments Using Household Substances
A i r Pressure - Experiment # z:
THE POWER OF THE AIR
Objective: To support a cup of water using air pressure.
Materials:
• * 8 oz paper cup
• 3 x 5 inch index card
SaSety Precautions: Do this over a sink in case of an accident!
Procedure:
1. Fill your cup to the brim with water.
2. Place a 3 X 5 card over the top of the cup. Make sure that the card covers
the top of the cup completely. I f not, substitute with a larger card or a
smaller cup.
3. Holding your hand over the card, slowly invert the cup of water.
4. Remove your hand, and the card appears to be supporting the entire cup of
water!
Explanation: Air pressure is being exerted in all directions with a force of
14.7 lbs per square inch. Since the card has a total area of 15 square inches, air
pressure is exerting a force of over 220 lbs on the face of the card! - This is a far
greater force than the mere 8 oz of force exerted by the water in the cup. However,
since air is invisible, it appears that only the card is supporting the water in the
cup. This demonstrates that the invisible air around us is capable of exerting a
tremendous force.
150 Captivating Chemistry Experiments Using Household Substances
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