If a helium balloon is placed in a cold freezer, what happens in the balloon?
Why don't you try it? Of course, you can use an air-filled balloon with the same result.
Charles' law holds that for a given quantity of gas,
Here's an experiment you can ask your science teacher to do. Get some of the long thin balloons that balloon folders use, blow them up, and see what happens when you insert the balloon in a Dewar filled with liquid nitrogen.