An oxyhydrogen flame is a type of fire that happens when you mix together two gases called hydrogen and oxygen. These gases are very special because when they are combined in a certain way and then lit with a match or a spark, they make a flame that is really hot and bright.
Now, imagine that you are cooking dinner and you need to use a stove. The stove needs some kind of fuel to make heat so that your food can cook. Normally, you would use things like gas or electricity to make the stove hot, but with an oxyhydrogen flame, you don't need any of those things!
Instead, you can use the special gas mixture of hydrogen and oxygen to create heat and fire. When you light the mixture with a match or a spark, it creates a flame that is hot enough to melt steel! This is why oxyhydrogen flames can be used for things like welding and metal cutting.
But it's important to remember that playing with fire is very dangerous and should always be done safely and under the supervision of an adult. So, always be careful and use caution when working with an oxyhydrogen flame.