Which of the following is the correct combination to cause fire?

which of the following is the correct combination to cause fire?

Which of the following is the correct combination to cause fire?

To understand the correct combination needed to cause a fire, it’s essential to look at the Fire Triangle, which consists of three elements: heat, fuel, and oxygen. These three elements must be present for a fire to occur. Let’s examine each component in detail.

1. Heat

Definition and Role: Heat is the energy necessary to increase a substance’s temperature to the point where it ignites. It is the spark or energy source that raises the material to its ignition temperature.

  • Sources of Heat: Heat can be introduced by various methods, such as:

    • Matches or lighters (open flames)
    • Friction (rubbing two sticks together)
    • Electrical sparks (faulty wiring or short circuits)
    • Sunlight (using a magnifying glass to focus sunlight)
  • Understanding Ignition: Each material has a specific ignition temperature. Reaching this temperature is critical for starting a combustion process. For example, wood requires a certain amount of heat to begin burning.

2. Fuel

Definition and Role: Fuel is any material that can be consumed to produce energy or maintain combustion. In a fire, fuel is what burns and sustains the fire.

  • Types of Fuel:

    • Solid: Wood, paper, coal — these are materials that need to be broken down into smaller particles to burn efficiently.
    • Liquid: Gasoline, alcohol — flammable liquids that vapourize easily.
    • Gas: Propane, natural gas — these do not require vaporization and can ignite easily with the presence of a spark.
  • Characteristics of Fuels: Different fuels have different burning characteristics, such as:

    • Efficiency: Some fuels burn more efficiently, producing more energy for the same amount of material.
    • Rate of Combustion: How quickly a fuel burns, and turns into flames, can affect how fast a fire spreads.

3. Oxygen

Definition and Role: Oxygen is a chemical element that supports combustion. For a fire to burn, it needs a sufficient amount of oxygen from the air.

  • Oxygen Concentration: Typically, air contains about 21% oxygen, which is adequate for normal combustion. However, lowering the oxygen level can slow or extinguish a fire, while increasing it can make a fire burn more intensely.

  • How Oxygen Interacts in Fire: During combustion, oxygen reacts with the fuel source, releasing heat and light. This reaction sustains the fire until one of the three elements (heat, fuel, or oxygen) is removed.

With this understanding, the correct combination to cause and sustain a fire is the presence of heat, fuel, and oxygen. These elements work together, creating a self-sustaining chemical reaction which we see as fire.


Summary: The combination required to cause a fire is the presence of heat, fuel, and oxygen. Removal of any of these elements will prevent or extinguish the fire. Understanding how these elements interact helps in fire prevention and safety measures.

If you have any more questions or need further clarification on specific points about fire and combustion, feel free to ask!