“Fire… begone!” These words aren’t magic, they’re science! We’ve harnessed the unique properties of a certain gas, carbon dioxide, to make our own version of a fire extinguisher. To understand how this works, we need to start with an understanding of fire. Fire requires two things in order to continue burning: fuel and oxygen. Without those fire will cease to exist. Our homemade fire extinguisher deprives fire of the second ingredient: oxygen.
We start with some dry ice. Dry ice is simply the solid form of carbon dioxide. When the dry ice heats up, it sublimates and turns into its gaseous form. Carbon Dioxide in its gas form is invisible and very dense. It’s density allows you to scoop it in a pitcher the same as you would a liquid, except that you can’t see it. When poured out it is heavy enough to push away all of the oxygen around the fire. No oxygen, no fire! Tada!