Is fire something special? Yes, it is oxygen in the air mixing with a fuel such as candle wax or coal so quickly that it gives out lots of heat.
When you think of a fire, you think of a flame. A flame is a mixture of gases giving off so much heat that they make any little particles of soot in the gas glow. What you see is glowing soot! You don't see the gases at all.
That is why a gas flame, for example, is hardly visible, while it is easy to see a candle or wood flame. Gas has hardly any particles of soot in, so it doesn't glow.
A fire needs something to burn, called a fuel. It needs oxygen, and it needs a way of getting very hot. Once the fuel is very hot, it will combine with the oxygen in the air all on its own.
Think of the way that people once made fire. They took two sticks (the fuel) and made a hole in one. They then twisted the pointed end of the other one very fast in the hole. The friction between the two pieces of wood gives out heat. When the wood gets hot enough by this means, the wood and oxygen mix very quickly and you have a fire. You see, all it needed was a fuel (two pieces of wood) and a a source of heat (fast rubbing). It didn't need a flame at all. The flame is the result of the heating.
There are lots of other examples. You can use a magnifying glass to concentrate the heat from the sunshine to make a piece of paper catch alight, for example.
We use matches because they are convenient, but even these work only because something gets hot. When you strike a match, you are rubbing a matchstick against a rough matchbox side. The match catches fire easily because the blob on the end is made of a material that catches fire at a low temperature.
So now you know how to make a fire, you also know how to put it out. You take away the fuel, you take away the oxygen (air) or you lower the temperature. It's often hard to take away the fuel (if it is a burning building, for example), so you lower the temperature by pouring water on to it from a firefighter's hose. The water also smothers the fuel with water, keeping air (and oxygen) away. This is why water is so good at putting out fires.
