What is fire? brief science behind it

What is fire? brief science behind it.

During our lectures in the forests, without fail we have a fire! Everybody loves a good old fire, but what is the point and the science behind it!

Let’s start with the science.

Fire needs three elements to function:

·         Oxygen

·         Fuel

·         Heat (Ignition)

The need for these three elements can be seen a weakness, when dealing with fire taking one of these is the first steps. In order to have a fire there must be a combustible solid or liquid present, this counts as the fuel. In a open space oxygen will always be present, mean that two sides of the fire triangle are already present, all that is left is just the heat (ignition). The term combustible means its ability to light/burn. All combustible materials have an ignition temperature, once this temperature is met the fuel will then ignite. At this point, if the heat is hot enough the gases will be drawn from the fuel causing combustion which creates a visible flame, this is the release of energy from the fuel and the more energy the longer it will burn.

When starting a fire do you use the biggest log you can find? No! you go for the smaller logs/twigs, this is because they have a lower ignition temperature or are composed of a more flammable composition. Twigs cannot sustain a fire for a prolonged amount of time, once a fire has reach a point of self-sustainment the addition of large logs can be applied.

Something we did as a bit of fun was to change the colour of the flame, this can be a simple process. Certain elements release chemicals, of which when ignited they will emit a different coloured flame, for example if the chemical strontium nitrate was ignited it would emit the colour red.