It’s easy enough to crumple a can using nothing more than your hands, but how do you crush a can without applying your own force to it? This is the ‘Self-Crushing Can’ experiment, it’s a bunch of fun to do and will only require very simple household objects as well as an adult helper. So, here’s what you’ll need: You will need:
A heat source (such as a hob or portable stove)
An empty can
An adult helper!
Start by filling your bowl with water, the colder the water the better! Place the bowl of water on a hard surface and grab your empty can.
Rinse out the can and add a quick splash of water to the top of it so that there is a small pool of water on the can’s surface.
Place the can directly on top of your hob or portable stove and tag an adult helper in to turn the heat on. After a while, you should hear the water on top of the can start to boil and you may even see the water vapor from the can start to rise.
Leave the can on heat for another minute while your adult helper prepares to take it off using the gloves and tongs. Once the minute is done, in one swift motion you’ll want to grab the can using the tongs, turn it over 180 degrees and plunge it into the bowl of cold water.
Assuming everything was done correctly, you should see the can immediately crumple in the pool of water. And that’s the self-crushing can experiment! But what caused the can to crush, can you figure it out?
The Science Bit: The key to understanding this science experiment is breaking down everything that led to the can imploding. After all, there needs to be some force that crushed the can – but what is it? Do you remember the water vapor that appeared when the water on top of the can was being boiled? This was the water changing from a liquid to a gas. This water vapor pushes the air inside the can out into the atmosphere, leaving none left inside the can itself. When the can is plunged into the water, the water vapor is cooled and turned back into a liquid, however no air can rush in to fill the space that’s left because the only exit is submerged in water.
The implication of this is the implosion that you witnessed when performing this experiment. The cause of which is the air outside of the can exerting too much pressure on the can. In conclusion, the force behind the can crushing is the air-pressure being exerted from the outside.