The culprit causes illusion in the desert

Total reflection is the cause of the illusion of seeing water in the desert or on the road on a hot day.

Seeing that desert water is illusion occurs because of the temperature difference between the air layers.

The phenomenon of seeing water in the desert or on the road on a hot day is an illusion that occurs due to the temperature difference between the air layers.

The closer the air layer is to the ground, the more heated it is, the cooler the air becomes.

The heated air will expand causing the refractive index to decrease. The upper air layer is cooler, more dense and has a higher refractive index.

The difference in refractive index causes the light to bend. The closer to the ground the greater the angle of incidence of the ray. When the angle of incidence exceeds the value of the limited refractive angle, total reflection will occur, causing the light to shift upward and to the eye.

Our eyes look in a straight line, resulting in the reflection of the sky above the earth creating illusions like puddles.