The old childhood pastime of burning bits of paper (and maybe ants) with a magnifying glass has upped its game. This video comes from the guys at LET'S MELT THIS, who use a Fresnel lens to turn sunbeams into penny-melting death rays.
A Fresnel lens has the ability to concentrate sunlight, in a similar way to a magnifying glass. Along with all that light energy, which becomes condensed into a small area, a lot of heat energy is also channeled into the area.
But instead of using a chunky convex lens to focus light like a magnifying glass, the Fresnel lens uses a series of ridged concentric rings. This allows them to be much lighter and thinner, hence making them more of a practical option.
The ridged concentric rings of a Fresnel lens, currently in use at the Cape Blanco Lighthouse, Oregon. Kirt Edblom/Flickr. (CC BY-SA 2.0)
They were originally created in the 1800s by the French physicist Augustin-Jean Fresnel (so they’re pronounced with a silent “s”) to use in lighthouses as the beam can be seen farther away. The lens has also had its uses in car headlights and television projection systems. And now, the inevitable next step of progress has come: to melt one cent coins. Check out the video below.