Let's find out what the air inside a balloon does when exposed to different temperatures of heat and cold.

Some brave student can blow up a balloon. Not so hard! We don't want it to burst!

Soon as it is inflated, another student can measure it's circumference (that is the distance around the balloon at the widest part). Be sure to write down all measurements.

Now, we'll float it in hot water for about ten minutes, and measure it's circumference again. Is there a difference? Did the air inside the balloon expand with the heat?

The next thing to do, of course, is to put it into a bowl of ice cubes for another ten minutes, and measure the circumference for the third time. Did the air inside the
balloon contract with chilling?

If it is available, we should get a balloon that has been inflated with helium, and see if it expands more or less (and contracts more or less) than the air we put into it when we blow it up by mouth.

I guess that when we blow up a balloon by mouth, we put carbon dioxide into it. This writer doesn't know for sure, so we'll have to be detectives and find out from a source with correct information.