In this Resources video, Science Facilitator Sam demonstrates 3 different air cannons and talks about the science of moving air.
We often think of air as being something light and weightless. In reality, air is a gas that takes up space and has mass (weight). Since there is a lot of "empty" space between air molecules, air can be compressed to fit in a smaller volume. Sometimes it is difficult to think about air and what it does because it is invisible. The air cannon is a way to 'see' air as it moves objects within its 'blast zone'.