Why do we see mirages, relating to refraction?

We see mirages due to the refraction, or bending, of light as it passes through air layers of different temperatures.

Mirages are fascinating optical phenomena that occur when light rays bend as they pass through air layers of varying temperatures. This bending of light, known as refraction, causes the light rays to follow a curved path instead of a straight one. As a result, the image of an object appears to be displaced from its actual position, creating the illusion of a mirage.

The process begins when the ground is heated by the sun, warming the air just above the surface. This warm air is less dense than the cooler air above it, leading to a change in the refractive index - a measure of how much light is refracted when it enters a medium. As light travels from the cooler air into the warmer air, it speeds up and bends towards the normal (the line perpendicular to the surface at the point of incidence). This bending of light continues as it passes through the different air layers, causing it to follow a curved path.

When our eyes receive these refracted light rays, our brain interprets them as if they had travelled in a straight line. This results in the image of the object appearing to be higher or lower than it actually is. For example, in a desert, the hot air near the ground can refract light from the sky to create the illusion of a pool of water on the ground. This is a type of inferior mirage, where the mirage appears below the actual object.

In summary, mirages are caused by the refraction of light as it passes through air layers of different temperatures. This bending of light results in the displacement of the image from its actual position, creating the illusion of a mirage.