Try blowing up a balloon using dry ice! Dry ice can blow up a balloon by filling it with carbon dioxide as the dry ice sublimates.
How could something as cold as dry ice blow up a balloon?
Remember that dry ice expands into carbon dioxide gas when it sublimates, or turns into a gas. This experiment shows you how that works. Make sure to follow all dry ice safe handling precautions.
Notice how the balloon filled with carbon dioxide gas falls quickly to the ground?
That's because carbon dioxide is heavier than air.
Wearing insulated gloves and using tongs, pick up a piece of dry ice and touch it to the balloon that you blew up with air (not the one you filled with carbon dioxide). What happens to the balloon?
Can you guess why?