Fire Extinguisher!

Activity: Putting Out the Light

If you are off to enjoy the fireworks displays this weekend, you might feel inspired to try some fire activities of your own, or perhaps you are wondering about the best way to put the flames out!

You will need:

Small candle (like a nightlight) and matches
Vinegar, hot water (from the hot tap) and bicarbonate of soda
A jug with a lip that you can pour from
Another container to mix the water and vinegar

What to do:

In your container, prepare a hot water and vinegar mix, (50-50 of each).
Light the candle.
Put about a dessertspoon of baking powder in your jug, then pour on the vinegar-water mix.
Let the fizz subside for a second or so, then take the jug and carefully ‘pour’ the carbon dioxide produced in the fizzing, over the candle. It will go out, ‘suffocated’ by the lack of oxygen.

What’s going on?

A candle burns in oxygen, combining oxygen with the chemicals that make up the candle wax creating water, carbon dioxide and a bunch of other bits and pieces. If you remove the oxygen, or displace it, the candle will go out.
The mix of baking powder and vinegar produces carbon dioxide gas in the fizzing that you see. Carbon dioxide is heavier than air so when you lean the jug over the candle carbon dioxide pours out and sinks onto the flame extinguishing it.
This experiment comes from Planet Science’s Little Book of Experiments – have a look here for more science things to do with candles and other stuff you’ll find in your home.