What Is a Fire and How Does Smoke Follow You?

Fire is a special chemical reaction that takes place between fuel, oxygen and an ignition source – such as lightning or a match. Once the fuel is heated to its ignition temperature, it will continue burning as long as heat is supplied and a supply of oxygen is present. This combination of heat, fuel and oxygen is called the fire triangle.

Fires burn because they release large amounts of energy through the process of combustion. During this reaction, the atoms in the fuel break apart, or combust, and rejoin with oxygen from the air to produce new molecules – water (H2O) and carbon dioxide (CO2). The fuel releases a lot of heat energy through this process, which creates a flame. The flame emits visible light and infrared radiation. The color of the flame depends on its chemical composition. For example, the flame produced by burning a solid material like wood or charcoal produces orange and yellow light because of the incandescent particles it contains. The flame produced by the complete combustion of methane gas, found in natural gas or at home from a stove or oven, produces a blue glow because it ionizes the surrounding gases.

Why does smoke seem to follow you? Smoke rises primarily because the hot, less dense air near the fire rises and is replaced by new air moving in from all directions. Since the new air is less dense, it moves upward as well. The direction the smoke travels is also influenced by gravity and the air density.

When a person stands too close to a fire, they are blocking the flow of air. This causes the smoke to move in front of them, or follow them. The reason it seems to “follow” the person is that the smoke is trying to get around the person, or fill in the space created by their body.

Fire is a dangerous and destructive force that can quickly spread through a building or forest. It is essential that you understand what fire is, and that you have an escape plan in case of a house or apartment fire. It is important to practice your escape plan regularly. Make sure that you and your family know at least two unobstructed exits from each room, including windows. It is also a good idea to have an outside meeting place for everyone to go to if you must leave your home during a fire. Make sure your family knows where to meet and that they are familiar with the route to the meeting spot. You should also practice your escape plan with younger children on a regular basis. This will help them feel confident and allow them to react quickly in the event of an emergency. For more information on creating an escape plan, visit our Fire Prevention page.