In a desert, a mirage is caused when air near the ground is hotter than air higher up. As light from the sun passes from cooler to warmer air, it speeds up and is refracted upward, creating the image of water.
An electric oven uses one kilowatt-hour of electricity in about 20 minutes, but one kilowatt-hour will power a TV for 3 hours, run a 100-watt bulb for 12 hours, and keep an electric clock ticking for 3 months.
