Mirage on the Road

If you've ever thought you saw a pool of water or some dark shadows lying across the road on a hot, clear day, you've seen a mirage. Don explained what actually happens.

On a hot, sunny day, the air just above a road heats up. As the air heats, it expands and becomes less dense than the cooler air higher up. Light can't travel in straight lines through air that varies in density, so when light from the sky passes from the cool air above to the hot air close to the ground it is refracted, or bent towards the viewer. The result is that we see what looks like a reflection of the sky, or a pool of water on the road in the distance. A hot surface bends light and creates an optical illusion, or mirage.

Copyright CTC Productions 2001