What is flame made of

This is known as the fire triangle. Combustion is when fuel reacts with oxygen to release heat energy. Combustion can be slow or fast depending on the amount of oxygen available. Combustion that results in a flame is very fast and is called burning. Combustion can only occur between gases. Fuels can be solids, liquids or gases. During the chemical reaction that produces fire, fuel is heated to such an extent that if not already a gas it releases gases from its surface. Only gases can react in combustion.

Gases are made up of molecules groups of atoms. When these gases are hot enough, the molecules in the gases break apart and fragments of molecules rejoin with oxygen from the air to make new product molecules — water molecules H 2 O and carbon dioxide molecules CO 2 — and other products if burning is not complete.

The heat generated by the reaction is what sustains the fire. The heat of the flame will keep remaining fuel at ignition temperature. The flame ignites gases being emitted, and the fire spreads. As long as there is enough fuel and oxygen, the fire keeps burning. In complete combustion, the burning fuel will produce only water and carbon dioxide no smoke or other products.

Some of the decomposed material is released as volatile gases. We know these gases as smoke. Smoke is compounds of hydrogen, carbon and oxygen. The rest of the material forms char , which is nearly pure carbon, and ash , which is all of the unburnable minerals in the wood calcium, potassium, and so on. The char is what you buy when you buy charcoal. Charcoal is wood that has been heated to remove nearly all of the volatile gases and leave behind the carbon. That is why a charcoal fire burns with no smoke.

A side effect of these chemical reactions is a lot of heat. The fact that the chemical reactions in a fire generate a lot of new heat is what sustains the fire. Many fuels burn in one step. Gasoline is a good example. Heat vaporizes gasoline and it all burns as a volatile gas. There is no char. Humans have also learned how to meter out the fuel and control a fire. A candle is a tool for slowly vaporizing and burning wax. As they heat up, the rising carbon atoms as well as atoms of other material emit light.

This "heat produces light" effect is called incandescence, and it is the same kind of thing that creates light in a light bulb.

It is what causes the visible flame. The fuel might be wax on your birthday candle or newspaper in a fireplace. These items are typically made up of molecules that contain carbon and hydrogen atoms. So, it appears the flame is floating. The final ingredient we need to make fire is oxygen.

And to understand why oxygen is so important in the reaction, we need to know a little more about how atoms work, Finnegan said. Atoms have particles called electrons. Most atoms want more electrons. They can often get them by sharing electrons with another atom.

If an atom shares an electron it also gains an electron.