In this haunting, interactive artwork by Ned Kahn, an overhead fan draws air upward, imitating the updraft that occurs in the core of a tornado-spawning thunderstorm. Air blowing from the sides of the aluminum tubes starts the updraft spinning, creating an air vortex, a small-scale tornado. A fog machine injects tiny droplets of water that make the airflow visible.
The tornado vortex is one of many types of vortices that occur in our atmosphere. Hurricanes, waterspouts, and dust devils are other examples of atmospheric vortices.
Air vortices occur in the air around you all the time, revealing themselves only when they capture something you can see. For instance, when you see leaves whirling around on a sidewalk, an air vortex is present.
Photo © Paul Doherty. (click image to enlarge)