2B30.15 - Pop Can Collapse
Demonstrate that the pressure of steam is much less than air at room temperature.
Overview: Use only about 1/8 inch of water in can. Make sure that the interior of the can is fully saturated with steam before inverting. Practice the inversion move with cool empty can. The sudden condensation of the steam in the can will cause the can to collapse abruptly and violently as the atmospheric pressure is much greater than the air pressure in the can.
Analysis: A difference in air pressure inside and outside the can causes a dramatic collapse. When the can is inverted and dipped in water, the hot steam cools and condenses back into water. As the temperature goes down quickly, so too does the pressure. Since there is no open path between the air inside the can and outside the can (the opening is now underwater), the can is not strong enough to support the difference in pressure, therefore it collapses. This vividly shows how powerful a force difference can be.