Explain the formation of mirage.

Normally, light waves from the sun travel straight through the atmosphere to your eye. But, light travels at different speeds through hot air and cold air.

Mirages happen when the ground is very hot and the air is cool. The hot ground warms a layer of air just above the ground.

When the light moves through the cold air and into the layer of hot air it is refracted (bent).

A layer of very warm air near the ground refracts the light from the sky nearly into a U-shaped bend. Our brain thinks the light has travelled in a straight line.

Our brain doesn't see the image as bent light from the sky. Instead, our brain thinks the light must have come from something on the ground.

In hot desserts , the sand becomes hot and layer of aur near to itbecomes very dense.The layers above it are less denser.So their refractive index will be different.Thus when we move from one layer to another, there will be phenomenon of refraction.Thus passing through different layers, when incident angle is greater than critical angle there is phenomenon of total internal reflection.Thus the rays move back and when it reaches the eye of a person, he see the inverted image called mirage.

A Mirages is an optical phenomenon that creates the illusion of water and results from the refraction of light through a non-uniform medium. Mirages are most commonly observed on sunny days when driving down a roadway. As you drive down the roadway, there appears to be a puddle of water on the road several yards (maybe one-hundred yards) in front of the car. Of course, when you arrive at the perceived location of the puddle, you recognize that the puddle is not there. Instead, the puddle of water appears to be another one-hundred yards in front of you. You could carefully match the perceived location of the water to a roadside object; but when you arrive at that object, the puddle of water is still not on the roadway. The appearance of the water is simply an illusion.