This is not an ordinary magnifying glass but a Fresnel lens, and its power is beyond imagination. When a banana is placed under it, smoke quickly rises, and the fruit carbonizes, breaking into two pieces. A Nokia phone lasts only seconds before bursting into flames and turning to ash. Even volcanic rock cannot endure, transforming into obsidian in under a minute. The Fresnel lens focuses sunlight into a single point, creating temperatures over a thousand degrees—enough to melt iron into liquid m

Fresnel Lens Manufacturing - 2018 Michigan Lighthouse Alliance Conference