Grade 6 (age 11-12)

Combustion & Fire Extinguishing

A flame needs three things at once: a fuel to burn, oxygen from the air, and a temperature above the ignition point. Take away any one and the fire goes out by itself, which is how water or a lid stops it. After burning, carbon dioxide and water are left behind. Here you can toggle each condition and see when the fire lights and dies.

What is Needed for Fire?

🔥 Three Elements of Combustion

①Combustion needs three things together

②Fuel: wood, paper, gas, etc.

③Oxygen: fire needs oxygen to burn

④Temperature above the ignition point

⑤Remove any one and the fire goes out!

Three Ways to Put Out Fire

🧯 Principles of Extinguishing

①Remove fuel: shut gas valve or move wood away

②Block oxygen: cover with lid, blanket, or extinguisher powder

③Lower temperature: spray water

④Extinguishers do oxygen-blocking + cooling at once

Products of Combustion

Combustion Reaction

Fuel + Oxygen → CO₂ + Water (vapor) + Heat

Burning produces carbon dioxide and water

💡 Combustion Products

①Burning a candle releases CO₂ and water vapor

②CO₂: turns limewater cloudy (test)

③Water vapor: drops form on cold glass (test)

④Incomplete combustion → soot (carbon)

Summary

Conditions for Combustion

Fuel + O₂ + Temp ≥ ignition = Combustion

All three needed for fire

Principle of Extinguishing

Remove one of the three = Extinguish

Remove fuel, block oxygen, or lower temperature

🎯 Key Points

①Combustion needs: fuel + oxygen + heat (≥ignition)

②Remove any one → fire goes out (extinguishing)

③Combustion produces CO₂ and water vapor

④Extinguishers cut O₂ and lower temp together

⑤In a fire: cover nose/mouth with wet cloth, stay low, evacuate

Examples and Unit Test

Example 1

A candle covered fully by a glass goes out shortly after. Which of the three conditions for combustion was removed?

Combustion needs fuel, oxygen, and a temperature above the ignition point.

Covering it with a glass stops fresh air, so oxygen runs low.

▸ Oxygen (air) was cut off

Removing any one of the three conditions puts the fire out; that is how extinguishing works.

Example 2

After a candle burns, what substances form, and how do you confirm the carbon dioxide?

Burning a candle produces carbon dioxide and water (vapor).

Carbon dioxide is confirmed because it turns limewater cloudy.

▸ Carbon dioxide and water / limewater turns cloudy

Combustion uses oxygen and releases carbon dioxide and water.

Unit-test style

Which statement about combustion and extinguishing is correct?

①Combustion does not need oxygen

②Spraying water to lower the temperature can put out a fire

③Extinguishing means providing all three conditions for combustion

④Burning a candle creates new oxygen

⑤A fire lights easily below the ignition point

▸ ② Spraying water to lower the temperature can put out a fire

Lowering the temperature below the ignition point breaks a combustion condition, so the fire goes out.

Combustion needs oxygen (①), extinguishing removes a condition (③), burning produces carbon dioxide and water (④), and a fire needs a temperature above the ignition point (⑤).

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Use of Electricity