What Is Fire and How Does It Affect Us?

Fire is a fascinating phenomenon that has captivated humans for as long as we have known about it. It is one of the four classical elements along with earth, air and water, but it has many modern applications as well. Nearly all of us use fire every day – to run cars and cook food. In addition, we depend on it to heat our homes and generate electricity in power stations that convert coal, oil and natural gas into electrical energy by igniting them in a chemical reaction called combustion.

Fire also provides us with the light to see by by releasing energy in the form of heat and light. Interestingly, light from a fire is emitted by a chemical that is released during the process of burning a fuel and oxidizing it with oxygen. Often, the release of that chemical is what we know as smoke.

It is this chemical reaction that releases the light we see as fire, but it can’t happen without all three of the other components that make up the Fire Triangle – fuel, oxygen and ignition. Fuel is any combustible material such as wood or gasoline. Oxygen is the air we breathe. And ignition is anything that starts the reaction, such as lighting a match or lightning.

Besides producing heat, the chemical reaction that causes fire produces a lot of light as it rearranges the molecules in the fuel to form new bonds with oxygen. That’s why fire is so bright.

Incomplete combustion, which produces smoke, occurs when the fuel doesn’t burn completely. The remaining fuel particles combine with the oxidizer and the heat to produce carbon dioxide and water. Those particles are too small to see with your eye and are released as smoke. Visible smoke is a collection of tiny solid, liquid and gas particles that are composed mostly of carbon (soot), tar and oils.

Wildfire is a natural ecological process that is an essential part of the ecosystems in which it occurs. It helps clear the forest floor and allows more sunlight to reach plant roots and soil. It also stimulates growth by releasing nutrients that are found in the ash that floats on the ground after a fire.

Some plants and animals depend on the effects of fire to survive or reproduce. For example, the lodgepole pine tree (Pinus contorta) stores its seeds in cones that require burning to open and release them. And the endangered Karner blue butterfly caterpillar (Lycaeides melissa samuelis) lays its eggs in areas where there have been recent fires. These caterpillars feed on the leaves of the wild lupine (Lupine perennis), which grows in and around burned areas. In some cases, these plants and animals are the first to recover after a wildfire.