Compact blowers inside the air pucks allow them to hover just above the floor so that they move with minimal friction (and eliminate the need for a costly air table for two-dimensional collisions). To create balanced air pucks of unequal mass, we added to the top of the puck a circular acrylic plate, which was held in place with VELCRO© brand fasteners for easy removal. Students record the collision between two pucks using a digital video camera connected to a computer to capture an AVI or MOV file.