Sometimes you need to crush an empty can, but it’s kind of boring just to stomp on it! Instead, put science to work for you and let the can crush itself!
What You Need
Empty pop can
Tongs
Heat source (a candle will do)
Pan or shallow tub of cold water
What you do
1. Fill a shallow pan or tub with water. There should be enough water to go part way up the pop can.
2. Add a small amount of water to the pop can.
3. Using the tongs, hold the pop can over the heat source, open side up. Hold it there, moving the pop can slowly from side to side until you see steam appear. You could also place the pop can on a stove burner or barbecue grill if you prefer.
4. Carefully and securely grasp the pop can with tongs and quickly invert it into the water. The opening of the pop or soda can should be submerged in the water.
5. Be prepared for the implosion! The can just crushed itself!
Explanation
By adding heat to the pop can with a bit of water, the water turns from a liquid into a gas. This gas is water vapor which pushes air inside the pop can out. When the can is turned over into the pan of water, the water creates an airtight seal.
The cold water cools the air inside the can and the pressure rapidly changes. The air outside the pop can can’t get in because the water in the dish is creates an airtight seal on the can.
As a result, the air pressure outside of the can is higher than the air inside the can. The can isn’t strong enough to resist - and the can collapses under the presser. This is called an implosion: something collapsing or squeezing into itself.
When you lift the crushed pop can up, you might notice it is filled with water. This water is pushed into the pop can as the pressure equalizes.
Taking it further
The physics of this demonstration are similar to the Water Lifting Candle demonstration. Why does the pop can implode, while the glass or jar do not?
Things to note
Be sure to have water in the pop can. The water is needed to create water vapor.
You may want to have oven mitts to hold the pop can.
Any time you are using a heat source, take extra safety measures.
Always wear safety glasses.
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