Interesting Physics - Photographs

Turbulences in air

One can create nice turbulent flows by reacting ammonia and hydrogen chloride evaporating from ammonium hydroxide and hydrochloric acid. By vibrating a strong laser we create a light plane that visualises the resulting microscopic particles of ammonium chloride. Photographing this with a camera set to about 1/4 s shutter speed, we see this way a planar cut through the smoke that shows turbulences of an unusual beauty (in reality it is even much nicer than in the photographs). We can see the same structure repeated in some pictures (e.g. the second one in the first row) because the laser beam ran several times across during the exposure time and so the smoke was caught at several different moments.