DIY Fire Extinguisher | Baking Soda and Vinegar

Have you ever sat around a campfire and watched it dance and glow? Have you ever wondered about the science of fire? We know it is hot. We know it needs something to burn, like paper or wood. We know it is usually orange or yellow, depending on the materials that are being burned. And we know that it needs oxygen to “stay alive”.

There are several different ways to deprive a fire of oxygen so that it will go out. You can dump water on it. You can put something like dirt or sand on top of it. For small fires, like candles and matches, you can simply just blow on it.

DIY Fire Extinguisher | Baking Soda and Vinegar

So why does a candle go out when you blow on it? One of the possible explanations is that when you exhale you breathe out a lot of carbon dioxide. That carbon dioxide displaces the oxygen around the fire, making it go out. Some fire extinguishers even use carbon dioxide (among other chemicals) to put out larger fires.

In this experiment we made our own fire extinguisher using vinegar and baking soda. The reaction of these two materials produces carbon dioxide, which you can see bubbling up through the solution. Carbon dioxide is heavier than air so it drops right on top of our candle to put the flame out.

DIY Fire Extinguisher | Baking Soda and Vinegar
This experiment can be found in The Usborne Science Encyclopedia, one of our favorite books that I consider essential in our home library.
Total Time: About 5 minutes
Safety Concerns: Use caution around fire and matches. Make sure your child understands that playing with fire is dangerous and that he or she can get burned severely, even with small candle fires.
Materials You Need:
A sturdy bottle (preferably glass)
A funnel
A small candle
5 Tbsp vinegar
1/2 Tbsp baking soda
  • Have an adult light the candle.
  • Add vinegar to your bottle.
  • Using a funnel, quickly drop the baking soda into the bottle.
  • Being careful not to spill your mixture, hold the bottle at an angle so the carbon dioxide can flow out onto the fire.
  • Notice how carbon dioxide is heavier than air and drops right onto the flame to extinguish it!

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