FRESNEL LENS SUN COLLECTOR Heating a Swimming Pool...

I like GREENPOWERSCIENCE. Dan Rohas makes interesting demonstrations of solar power using fresnel lenses (flat magnifiers - the size he uses is normaly used in phares) and parabols. For some reason things often bursts into flames, even when he's demonstrating how to heat your pool with solar power.

Of course you can boil water this way. Take a look at the sequel: