I'm assuming must everyone reading this is familiar with air hockey, but if not, an air hockey table is shown above. When started, air is blown through the tiny holes in the table. Each person grabs a paddle and uses the paddle to hit/push a puck. The puck is light enough and the upward force from the air is great enough to create a tiny bed of air between the table and the puck. In other words, it greatly reduces the friction force between the puck and table, allowing the puck to glide across the surface. That's it. Physics is the reason you can enjoy a game of air hockey. Without the air, one could still play, but it wouldn't be called air hockey and wouldn't be nearly as fun!