1. Combustion and flame
Class 8 By Rehet Kaur Bhatia 8D

2. Combustion and few facts about it
• Combustion is a chemical process in which a substance reacts
with oxygen to give off heat. Some substances may also give
light along with heat during combustion.
THE FACTS :
 Combustion Is an exothermic Reaction
 the mass after burning fuels was less than the original mass.

3. Combustible & Non – combustible
Substance
• Combustible Substance: A substance which can undergo
combustion is called a combustible substance. A combustible
substance is also called fuel. It can be solid, liquid or gas.
• Non-combustible Substance: A substance which cannot
undergo combustion is called a non-combustible substance.

4. Factors for combustion
a.A combustible substance
b.Oxygen
c.Ignition temperature: The
minimum temperature at
which combustion starts in
a substance is called
ignition temperature of that
substance.

5. How to control fire
• Fire Control:
• Fire can be controlled by removing
any or all the factors of combustion,
i.e. fuel, oxygen (air) and ignition
temperature (by lowering the
temperature).
• By using Water
• By Fire extinguishers
• By Towel
• By sand or Soil

6. Types of
combustion
• Types Of Combustion
• There Are Following Types Of Combustion:
• Rapid Combustion: When Combustion Happens At
A Faster Rate, It Is Called Rapid Combustion. Petrol
And Gas Show Rapid Combustion.
• Spontaneous Combustion: When Combustion
Starts On Its Own; Without An Apparent Cause; It Is
Called Spontaneous Combustion. For Example;
Coal Dust In Coal Mines Can Start Burning On Its
Own. Forest Fires Is Spontaneous In Most Of The
Cases.
• Explosion: When Combustion Reaction Is So
Sudden That It Releases A Large Amount Of Heat,
Light And Sound, It Is Called Explosion.
Firecrackers Explode Because Of This Type Of
Combustion.

7. Flame
Flame is the visible and gaseous part of fire.
Only those substances which vaporize on burning produce flame
Like : Kerosene And Wax
. If a substance does not get vaporized, it does not produce
flame.
Like : Coal and charcoal

8. Candle flame image
• A is the hottest zone as almost all
combustion takes place here .
• B is the moderate zone as moderate
combustion takes place here.
• C is the coldest zone as no
combustion takes place here .

9. Characteristics of a good fuel
1) Should cause less pollution
2) Should be cheap
3) . Ignite easily
4) Burn well, but not explosively.
5) Give out a lot of heat
6) Have low smoke

10. Calorific value
Heat Produced By
Burning 1KG Of
Fuel

11. Destructions of burning fuel
• Can Cause Asthma
• Burning of most fuels' releases carbon monoxide. It is a
poisonous gas
• Burning of most fuels results in release of carbon dioxide in
atmosphere.
• Oxides of Sulphur and nitrogen mix with rainwater; to cause
acid rain. Acid rain is harmful for living beings, buildings, and for
monuments.

12. This Photo by Unknown Author is licensed under CC BY