Good question Aaron. Did you see the dry ice that we had at the Grant School Halloween party? Gord O. knows all about dry ice, and here is his answer to your question.

Have you ever seen your breath on a cold day? Of course you have. This is what happens when you put dry ice in water. Dry ice is frozen carbon dioxide. Its temperature is -100 C. That's cold!

Carbon dioxide is supposed to be a gas at normal temperatures, so the dry ice is constantly changing into a gas. When you put it in water you see bubbles becuase it is changing into a gas. Since the gas is so cold (remember, -100 C), when the bubles reach the air, it causes the moisture in the air to condense, just like your breath on a cold day.