What is a heat haze?

The term heat haze is a general one that speaks to the ability to resolve (see with the eye) objects at a distance through hot air. When the air between the object and observer is hot and a number of tiny areas of "difference of temperature" exist, each little slight variation in temperature sets up different interference patterns in the light reflected or given off by the object. Remember that this light is trying to get from the object to the observer, and the air is "messing things up" for the photons. The result is that the object isn't sharply defined or clearly visible, but is "fuzzy" off in the distance there. As air moves slightly because it is a bit hotter and less dense than nearby air, distant objects can shimmer and otherwise move in the field of view making them hard to resolve. Most of us have seen this effect because it is sometimes used in film or television programs. Someone or something is coming toward the viewer (the camera) across a very hot desert or plain, and the figure can be distinguished as an individual moving closer, but details are unclear. As the person closes on the camera, he comes into better view. The heat haze has obscured him for a time, has kept details from the ability of the viewer to see them.