Conduct simple experiments to demostrate importance of air in combustion

Oxygen is the gas in the air that supports burning. Without oxygen, combustion cannot take place, even if you have fuel and heat. This is why we say air (oxygen) is very important in combustion.

This is a simple experiment you can do in class or at home with help from your teacher or guardian.

What You Need

• Two candles (label them A and B)
• A matchbox or lighter
• A transparent container with one open side or an airtight jar
• A table
• A watch or clock

What to Do

1. Place both candles on the table and light them.
2. Cover candle B with the airtight jar. Make sure the jar is sealed so no air can enter.
3. Leave candle A uncovered.
4. Watch both candles for one minute and note what happens.

What Will Happen

• Candle A (uncovered) will keep burning because there is enough oxygen in the air to support combustion.
• Candle B (covered) will burn for a short time and then go out. This happens because the oxygen inside the jar gets used up, and no fresh air can enter.

Why?

The covered candle goes out because there is no oxygen left inside the jar. This experiment shows that oxygen from the air is essential for combustion to continue.

This experiment proves that air (oxygen) is necessary for combustion. When oxygen is present, fuel can burn. When oxygen is removed, the fire stops. This is why fires go out when we smother them with water, sand, or a blanket — we are cutting off the air supply.

In Tanzania, cooks use charcoal stoves for cooking food. When the fire becomes too small, people sometimes blow on the charcoal to add more air. This brings more oxygen to the fire and makes it burn stronger again. Understanding that air (oxygen) is needed for combustion helps us control fires safely when cooking and heating.