What Fire Needs
Remove one side and the fire goes out.
What this lesson covers
Why it matters
A fire is a fussy guest: it needs fuel, oxygen and heat all at once. Take away just one of the three and the flames die instantly.
Predict first
A burning candle is covered with an upturned glass. After a few seconds the flame goes out. Which side of the fire triangle was removed?
A fire needs fuel, oxygen and heat together (the fire triangle). The glass sealed off the oxygen, so the flame went out.
- The fuel ran out
- The oxygen supply was cut off — correct
- The heat disappeared suddenly
- Nothing was removed; it just got tired
What you do
Sort each item into what a fire NEEDS to keep burning, or what PUTS a fire OUT by removing one of those needs.
Check yourself
What three things make up the fire triangle?
A fire needs all three of fuel, oxygen and heat. Take any one away and the fire goes out. This is the fire triangle.
What does ignition temperature mean?
The ignition temperature is the lowest temperature to which a fuel must be heated before it catches fire.
How do most fire extinguishers put out a fire?
Extinguishers work by removing part of the fire triangle: a carbon dioxide blanket cuts off oxygen, and water cools the fuel below its ignition temperature.
- Fuel, oxygen and heat — correct
- Fuel, water and heat
- Oxygen, nitrogen and heat
- Fuel, oxygen and carbon dioxide
- The lowest temperature at which a fuel catches fire — correct
- The temperature at which a fire finally goes out
- The temperature of the room where the fuel is kept
- The highest temperature a flame can reach
- By cutting off the oxygen or lowering the heat — correct
- By adding more fuel to burn it up quickly
- By blowing more air onto the flames
- By making the fuel colder than the room but still above ignition temperature