Okay kiddo, do you know what gas is? It's a type of substance that is all around us, but we can't see it because it doesn't have a color or a shape.
Well, adults use gas to do something called gas cutting. They use special machines that mix two types of gas, oxygen and acetylene, together. When these gases mix, they create a very hot flame. Much hotter than the flame you might see on a gas stove in your kitchen.
People use this hot flame to cut through things like metal. They put the flame at the spot they want to cut, and it melts the metal so they can separate it.
This process can be dangerous if not done carefully. So, adults wear protective gear and take safety precautions when doing gas cutting to make sure that no one gets hurt.