This Bag Balloons lesson plan also includes:
Students demonstrate that heat can change air. They determine that hot air rises. Students construct a working model of a hot air balloon. They understand that there are two ways that a balloon can rise: it can (1) be filled with a gas that is lighter than air, such as helium,or (2) it can be filled with air that is heated sufficiently to make it "lighter" than the air outside of the balloon.