Question

Если посмотреть на окружающие тела через теплый воздух, поднимающийся от костра, то они кажутся "дрожащими". Почему?

Answer 1

Происходит конвекция( теплый воздух поднимается вверх а его замещает холодный воздух)

Answer 2

Why objects appear "shimmering" when viewed through warm air rising from a fire

When we view objects through warm air that is rising from a fire, the objects may appear to "shimmer" or "dance". This is because the rising warm air causes the light rays passing through it to bend or refract.

Refraction is the bending of light when passing from one medium to another with a different density. In this case, the light rays are passing from the cooler air around us into the patches of warmer rising air between us and the objects in the distance.

As the temperature fluctuates slightly within the rising warm air currents, so does the density of the air. This causes the refractive index to vary across the air layer. Light rays passing through will bend slightly differently depending on the precise density of the air they pass through.

To our eyes, this appears as subtle movements or "shimmering" of the distant objects. It's an optical illusion caused by the fluctuating refraction of light through a medium with varying density. On a microscopic level, the light rays are being bent at slightly different angles by the unevenly heated air. But to us, it looks like the objects themselves are moving or dancing in the haze.

So in summary, the "shimmering" effect is due to the rising warm air currents causing light to refract unevenly as it passes through air of fluctuating density, creating the illusion that distant objects are moving when viewed through this refractive medium.