My friend Paul and I bought a 4 foot by 3 foot Fresnel lens this morning. The obvious thing to do with it, of course, is turn it into giant solar magnifier, so we constructed a 1,500 piece K'nex frame for it. By the time we were finished it was 7 in the evening so the sun was fairly low in the sky, but it still got hot enough to vaporize pennies with ease.
I plan to post a video soon when we get a chance to try it mid-day.
Paul holding the death ray, attempting to melt a railroad spike.
The welding mask is necessary to look at the spot, it would blind you otherwise.
The welding mask is necessary to look at the spot, it would blind you otherwise.