[TheTuds (OP)]

I'm doing a project on creating energy using the flow of water.  I have a basic idea of how turbines work but it would be cool to have a refresher. 

And also more importantly I have no idea where to find a little model turbine that can be fully submerged in water to do this project of mine.  Can anyone help a dude out?  I can't find it anywhere  []

_{Mod Edit - Formatted the subject as a question - please do this to help keep the forum tidy and easy to navigate, thanks!}

[chris]

Water turbines work the same way wind turbines do; all that differs is the density of the fluid that is moving them (air is considered by physicists to be a fluid too).

The turbine (wind, water or steam) comprises a balanced array of linked asymmetrical blades that are crafted so that as a fluid flows over the surfaces of the blades there is a pressure drop at the back-edge of the blade, which pulls the air towards the blade surface.

But Newton's 3rd Law says that for every action there must be an equal and opposite reaction, so the blade is pulled back towards the air, causing it to feel a force, which makes it turn.

A propeller is the same science but in reverse - energy is put into the propeller which pushes on the air, which pushes back; the result is propulsion.

Chris