Fire can be many things. Warming. Destructive. Beautiful. But how does it work? How does something catch on fire? How can you start a fire, keep a fire going, or put out a fire? When you attain a degree in fire sciences, you will learn about the complex nature of the chemical reactions it takes to start a fire. For now, we have a short, fun, and informative, overview of how fire works and what it needs in order to burn.
Ultimately, fire is a chemical reaction – if oxygen in the air meets with some kind of fuel that’s been heated enough, fire can be ignited. So what kind “fuel” can start a fire?
- Friction: rubbing two pieces of wood together hard enough or long enough creates heat, plus the oxygen in the air can create a fire. This is also what happens when you strike a match.
- Focused or concentrated light: Magnifying the suns’ rays through glass or being exposed to a strong light long enough can create heat that can spark a fire.
- Heat: Sometimes heat that is nearby, caused by something that isn’t movement or light, such as cooking or electricity, can cause something to heat up enough to catch on fire.
- Gasoline (or other flammable substances): These ingredients are called flammable for a reason. In the right combination, they can increase the likelihood of fire. If the other two elements above (friction and light, both causing heat) aren’t enough to spark a fire, a straight chemical fuel like gas can get a fire going.
Once a fire is burning, it needs energy to stay lit. Energy comes in the form of substances that interact with the fire and oxygen around it– like wood or paper or anything that can be heated and catch fire. A backyard bonfire can be kept steadily lit with blocks of wood because that is a good supply of energy for a fire to work its way through – splinters and newspaper would burn too quickly because they have a much smaller mass. Similarly, a wildfire is incredibly hard to put out because it usually starts in places of almost unlimited energy – a prairie or a forest will stay lit for a long time, and strong winds in those areas spread the fire and add large bursts of oxygen.
Knowing how to stop a fire is an important part of the life of a fire. Putting out a fire means hindering the oxygen supply, reducing the heat, and cutting off access to the fuel that it is burning – what method you use depends on the type and size of fire. For instance, fires started with hot oil or electricity should not be put out with water – oil floats on water and can spread the fire. In those cases, baking soda, a fire blanket, or fire extinguisher will work. While water WILL work on large forest fire cannot be put out with small buckets of water or a single fire extinguisher – professionals use huge, powerful tools to attack a fire, including high powered water hoses and fire retardant foams.
Fire is a powerful event, often watched or feared and never understood. Just knowing the science and energy of fire certainly won’t tame a fire, but it can add a dimension of appreciation and preparation.