A fire extinguisher is employed to put out small fires before they get out of control. The extinguisher has to suffocate the complete fire as fast as possible. It can do this by spraying a powerful jet of water, foam, or powder. Some fire extinguishers can discharge a spray of carbon dioxide (a heavy gas which prevents burning). The type of extinguisher used will vary with the type of fire tackled, for example dry powders are used for electrical fires where water would be inappropriate.
A fire extinguisher works in a similar way to the spray can. The contents are put in the cylinder under extremely high pressure. This pressure is then used to force the substance out through the nozzle when the extinguisher trigger is pressed.
