posted on Dec, 31 2006 @ 05:24 AM
I didn't see a post on this yet, so here it is.
A fresnel lens from a large projection TV will burn through a pop can in less then 7 seconds (700-900watts-about 800Deg C) just from the suns power.
So get one of those next time some one tosses one out. You could boil water with this and if you know how to make a small steam engine, you could get
power from it as well. There are also fresnel lenses that can be rolled up but they are much smaller.
You can also make a lens from plastic wrap, a 4-8" wooden ring and water. You hold the wrap around the edge of the ring and pour water into it and
allow the plastic to deform to become almost spherical and hold it over what ever you want to burn. You might be able to do the same with water filled
condoms, not that they will really have another use if you need to repopulate the earth.
You cand make solar ovens too. They trap heat and light to cook things and can reach 150Deg. C. They can be made with aluminium foil and glass!