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SAI International School
Subject - Chemistry
Class - VIII
Topic – Combustion and Flame
Sub-Topic-Conditions required for combustion

LESSON NOTES

Conditions necessary for combustion

Three conditions are necessary for the process of combustion to take place. These are:

1. Presence of a combustible substance. (presence of a fuel)
2. Presence of supporter of combustion. (air or oxygen)
3. Heating the combustible substance to its ignition

temperature. Let us discuss in detail about these conditions.

1. Combustible substance
The presence of a combustible substance is necessary for combustion to take place.
For example, if we have to start a fire we use combustible substances or fuel like
cloth, paper, wood, etc.

2. Supporter of combustion
The most common supporter of combustion
which wehave around us is air or oxygen.
We can say that air is necessary for
combustion. In class 6 you have read that
oxygen or air is necessary for burning.
We can explain the need of oxygen in
combustion by the activity which has shown
below.

3. Ignition temperature
The lowest temp[erature at which a substance catches fire and starts burning is called
its ignition temperature.

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