Fragrant stick smoke

The smoke raising from a burning fragrant stick provides a beautiful demonstration of turbulence - a remarkable physical phenomenon that has a very complicated explanation and still is not completely understood. As the hot smoke raises, the air friction creates vortices of various scales that may show chaotic behaviour and there can also be an oscillating motion. Turbulences are responsible for flickering of flags in a wind, creating the sound of "s" and "z", whistling of a whistle, formation of snow-drifts and many other phenomena.