Homemade fire extinguisher
Most people have fire extinguishers in their homes and in fact, we even place extra ones in the garage where Dad hangs out. All schools and businesses are required by law to have fire extinguishers on their premises. Fire extinguishers work by removing one of the critical ingredients for a fire – oxygen. In this experiment we demonstrate this process.
- Fill the small dish with baking soda.
- Place a short candle and a slightly longer candle upright in the baking soda
- Place the dish into the bottom of the large bowl.
- Have Mom or Dad light both candles. If Dad’s handling the matches then go get that fire extinguisher out of the garage first.
- Pour the vinegar into the dish of baking soda (not on the candles).
What happens to the candles? Which candle goes out first – the shorter one or the taller one?
When vinegar is combined with baking soda, the two react and produce carbon dioxide gas. The carbon dioxide gas is heavier than the surrounding air so it sinks into the bottom of the bowl. As the reaction continues, more and more carbon dioxide gas is produced which begins to slowly fill up the bowl. When the level of carbon dioxide has risen to the level of the flame, the flame will go out from lack of air.
Fire is the heat and light that comes from burning substances. In 1777, Antoine Lavoisier, a French chemist, proved that burning is the result of the rapid union of oxygen with other substances. As a substance burns, heat and light are produced.
Carbon dioxide is a colorless, odorless gas. It occurs in the atmospheres of many planets, including that of the earth. On the earth, all green plants must get carbon dioxide from the atmosphere to live and grow. Animals produce the gas when their bodies convert food into energy and living tissue. Animals release carbon dioxide into the atmosphere. Carbon dioxide is also created by the burning of any substance that contains carbon. Such substances include coal, gasoline, and wood. Fermentation and the decay of plants and animals also produce carbon dioxide. Carbon dioxide makes up less than 1 per cent of the earth’s atmosphere.