After drinking a can of soda, many just crush the can and throw it out in the garbage. However, have you ever thought about the air pressure you apply to it? To understand it better, try the collapsing can lab.
Procedure:
1. Fill a bowl with cold ice water.
2. Heat a hot plate or stove.
3. Fill a soda can with a little bit of water and wait for the water to boil.
4. When the water boils, a cloud of condensed vapor will escape from the opening in the can.
5.Allow the water to boil for about thirty seconds.
6. Using tongs, grasp the can and quickly, and carefully, invert the can and invert it into the bowl of ice water. The can will collapse almost instantly.
What Caused the Can to Collapse?
When the can was heated, it caused the water in it to boil. The vapor from the boiling water pushed air out of the can. When the can was filled with water vapor, it cooled suddenly by inverting it in ice water. Cooling the can caused the water vapor in the can to condense, creating a partial vacuum. The extremely low pressure of the partial vacuum inside the can made it possible for the pressure of the air outside the can to crush it.
Procedure:
1. Fill a bowl with cold ice water.
2. Heat a hot plate or stove.
3. Fill a soda can with a little bit of water and wait for the water to boil.
4. When the water boils, a cloud of condensed vapor will escape from the opening in the can.
5.Allow the water to boil for about thirty seconds.
6. Using tongs, grasp the can and quickly, and carefully, invert the can and invert it into the bowl of ice water. The can will collapse almost instantly.
What Caused the Can to Collapse?
When the can was heated, it caused the water in it to boil. The vapor from the boiling water pushed air out of the can. When the can was filled with water vapor, it cooled suddenly by inverting it in ice water. Cooling the can caused the water vapor in the can to condense, creating a partial vacuum. The extremely low pressure of the partial vacuum inside the can made it possible for the pressure of the air outside the can to crush it.
A can is crushed when the pressure outside is greater than the pressure inside, and the pressure difference is greater than the can is able to withstand. For instance, you can crush an open aluminum can with your hand. When you squeeze on the can, the pressure outside becomes greater than the pressure inside. If you squeeze hard enough the can collapses.
Usually, the air pressure inside an open can is the same as the pressure outside. However, in this experiment, the air was driven out of the can and replaced by water vapor. When the water vapor condensed, the pressure inside the can became much less than the air pressure outside. Then the air outside crushed the can.
When the water vapor inside the can condensed, the can was empty. You may have expected the water in the bowl to fill the can through the hole in the can. Some water from the bowl may do this. However, the water cannot flow into the can fast enough to fill the can before the air outside crushes it.
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