In hot summer, why does it seem that there is water on the road, but there is no water when you walk in?

The illusion of water: the reason for this phenomenon is actually that the difference of air temperature leads to the low air density below? , so as to produce total reflection, so that the light in the sky is reflected to the human eye and looks like water. The illusion of anger: the hot air below rises, resulting in different refractive indexes, and the distant light rays are refracted to varying degrees, leading to? In order to create the illusion of gas,

When light passes through the intersection of different density media, it will be divided into two parts. Part of the light is reflected back to the original medium, and the other part is refracted into another medium. The specific angle and energy of refraction are related to the incident angle. The smaller the incident angle, the weaker the refracted light and the stronger the reflected light. This explains why the water surface can only be seen on a long road. ?

Because the ground absorbs a lot of heat in summer, it is very hot, and the air near the ground is also heated. Because all objects follow the principle of "expansion with heat and contraction with cold", the density of air after expansion with heat and contraction with cold (you may not find it, but it does exist) is different from the surrounding air. When sunlight shines there through the air, it will be refracted because of different densities, and the optical path will change. ?

Seeing this layer of hot air flowing, just like water flowing, but it seems a bit hazy, not quite the same as the texture of water.

It is sunny in summer, and when it is hot, the temperature rises quickly because of the small heat capacity of air; The pavement has large heat capacity and slow temperature rise; In this way, the air temperature near the road surface is relatively low, but the density is relatively high, which makes the air become an uneven medium. In addition, in the distance, the incident angle and reflection angle of light are large, which makes the light refract repeatedly in uneven air to form total reflection, which has mirror effect. So it looks like there is water in the distance. On the contrary, if the incident angle and reflection angle of close-range light are small, the light will be absorbed by the road surface, and there will be no such feeling.