Humor me while I present a silly scenario: Let's say you find yourself at a carnival. While there, you play games, eat cotton candy, and get some balloon animals, meticulously crafted for you by a clown. You're so enamored with their craftsmanship that you get more and more and more until you have too many to fit in your car. Here's the thing, though: You love them so much that you need to bring them all home. How do you do it? You could try to squish them all in, but that presents a big popping risk. In this made-up situation, your best bet might be to freeze them, as the Real Physics Live channel on YouTube has taught us (via Geekologie).
In the video, we see a bunch of balloon animals dipped into a container of freezing cold liquid nitrogen, which pretty quickly causes the balloons to shrivel up. When they're taken out of the container and allowed to reach higher temperatures, though, they re-inflate and are brought back to life.
The simple explanation is that cool air takes up less space than warm air does, thusly allowing the balloons to revert to their non-inflated state. To get a bit more technical, though, what happens is that as the temperature decreases, the kinetic energy of the gas molecules reduces along with it. This means that the molecules are moving more slowly, which causes them to collide less frequently and less forcefully with the walls of the balloon, which leads to the deflation that you see. If you want to watch this for yourself, try it out in your freezer and bring your own balloon animals back to life.
If you can think of any other neat experiments that demonstrate how gas changes its behavior in different conditions, let us know down in the comments!
Featured image: Real Physics Live