Question
Wed November 28, 2012 By:
 

How does the phenomenon of mirage take place?

Expert Reply
Thu November 29, 2012

     

 
A mirage 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.
 
On sunny days as the surface of the earth warms up, the layers of air near to the earth also gets hot.As we move up in the atmosphere, the layers get cooler. so the  density of the layers also increases as we go up from the surface of earth.
Light that is traveling downward from the top of the object(as given in the fig,man on the camel)into this less optically dense air begins to speed up. Though there isn't a distinct boundary between two media, there is a change in speed of a light wave. As expected, a change in speed is accompanied by a change in direction. If there were a distinct boundary between two media, then there would be a bending of this light ray away from the normal. For this light ray to bend away from the normal (towards the boundary), the ray would begin to bend more parallel to the roadway and then bend upwards towards the cooler air. As such, a person in a car sighting downward at the roadway will see an object located above the roadway.
 
 
 
An inferior mirage occurs when the ground is very hot compared to the sky. Light reflected toward the ground from the sky bends back up as it travels through the hot air near the ground. To the viewer, it will look like the image is actually coming from the ground. Inferior mirages look like a patch of sky or a shimmering pool of water on the ground in the distance. It is called an inferior mirage because the image appears to be at a lower level than the actual object.

Read more: How Mirages Are Formed | eHow.com http://www.ehow.com/how-does_5114348_mirages-formed.html#ixzz2DaEZ8GbW
An inferior mirage occurs when the ground is very hot compared to the sky. Light reflected toward the ground from the sky bends back up as it travels through the hot air near the ground. To the viewer, it will look like the image is actually coming from the ground. Inferior mirages look like a patch of sky or a shimmering pool of water on the ground in the distance. It is called an inferior mirage because the image appears to be at a lower level than the actual object.

Read more: How Mirages Are Formed | eHow.com http://www.ehow.com/how-does_5114348_mirages-formed.html#ixzz2DaEZ8GbW
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