Burning glass

Burning glass is like using a magnifying glass to start a fire, but on a bigger scale! Imagine holding a big, round crystal lens on a sunny day. If you hold the lens just right, it can focus the sun's rays into a tiny spot of intense heat. It's like turning up the heat through a tiny hole! This heat is so powerful that it can burn things like paper or wood. So, if you want to start a fire, you can use a burning glass to focus the sun's rays onto some dry leaves or twigs until they catch on fire. It's important to be careful though, because the heat of the burning glass can be very strong and can also burn skin if you're not careful!