Vortex engine

Here is an interesting and intriguing topic which involves a lot of physics some of which is fairly basic. Perhaps good for an assignment? Cannot say how practical it is but looks impressive.

"AVEtec is the brainchild of Canadian engineer, Louis Michaud. His Atmospheric Vortex Engine (AVE) harnesses the physics of tornados to produce extremely cheap and clean energy. In his design, warm or humid air is introduced into a circular station, where it takes the form of a rising vortex, i.e. a controlled tornado. The temperature difference between this heated air and the atmosphere above it supports the vortex and drives multiple turbines. The vortex can be shut down at any time by turning off the source of warm air."