SUBJECT AREA: Physics Concepts including: Volume, Change of State, Volume of Gases, Atmospheric Pressure

MATERIALS:

1. One empty aluminum can (354 ml)

2. A Hot plate or burner

3. Large bowl of water

4. Tongs to hold pop can

PROCEDURE:

1. Put about 5 ml of water in the pop can (just enough to cover the bottom).

2. Heat the can over the hot plate or burner.

3. Let the water boil vigorously.

4. In a single motion, remove the pop can from the burner and INVERT it in the bowl of water.

5. Submerge the opening to the pop can in to the water. The can will IMPLODE instantly.

QUESTIONS:

1. What was in the can besides water?

2. What happens when water is boiled?

3. What do you think will happen if the can is inverted in the bowl of water?

4. What happens to the air in the can as water vapor is formed?

5. What force is working on the outside of the can?

RATIONALE:

Before heating, the can was filled with water and air. By boiling the water, it changes states, from liquid to gas (water vapor). The water vapor (steam) pushes the air that was inside, out of the can. By inverting the can in water, we are cooling the vapor very quickly and constraining the potential for rapid flow of air back into the can. The cooling condenses the water vapor back to water. All of the vapor which took up the interior space of the can before is now turned into a few drops of water, which take up much less space. This causes the pressure to drop and the atmospheric pressure is therefore pushing on the can and crushing it.

The total force working on the outside of the can is the total of the can's surface area in cm. multiplied by 1 kg.

APPLICATIONS:

Production of vacuum containers

Home canning