You must have used a magnifying glass to burn newspapers and wood as a child, but this is one step beyond as the Youtube Channel named “Let’s melt this” has managed to melt coins with the help of nothing but concentrated solar energy. Now normal magnifying glasses are far from being effective enough to melt metals, but this Youtuber has used fresnel lens to achieve that. Now this kind of lens has the same fundamental principle as a normal magnifying lens, but it does use a series of rings to help concentrate as much light at one point as possible. Here is the video of the amazing experiment:
So, basically, this lens was developed by Augustin-Jean Fresnel in 1800s to make lighthouse beams much more visible from large distances. Since they can concentrate light so well, they were eventually used in projectors as well. You can buy Fresnel lens from Amazon and have fun with it in your house. Just don’t treat it like a normal magnifying glass as it was far too dangerous.