How can gas extinguish a fire?
Three things must be present for a fire to occur: Combustible material, oxygen (air) and heat. This is often referred to as the fire triangle. To extinguish a fire, we must remove at least one side of the triangle.
In this experiment we use CO2 gas to extinguish the fire. CO2 gas is heavier than air. The gas settles at the bottom of the tub, so the shortest light goes out first.
NB! Experiments must always follow the safety rules that apply to laboratory experiments. Remember protective gloves and goggles.
You need:
• Protective gloves and goggles
• A transparent tub or a small aquarium
• Some candles of different heights
• Baking soda and acetic acid (household vinegar)
• A measuring jug
• A long-neck candle lighter
Recipe:
1. Wear safety goggles and gloves
2. Place the candles in a row in the transparent tub
3. Light the candles.
4. Mix some baking soda and acetic acid (household vinegar) in a measuring jug. The mixture produces carbon dioxide gas
5. Pour the gas into the aquarium and see what happens!
Here is the chemical formula for what you see:
NaHCO 3 + HC 2 H 3 O 2 → NaC 2 H 3 O 2 + H 2 O + CO 2
The CO2 gas is heavier than air. The gas settles to the bottom of the tub and the shortest light goes out first.
