why does water put out fire?

Answer 1

Fire needs air and water takes that away.

Answer 2

To have a fire, you need three things: fuel, oxygen, and heat. Remove any one of those and you won't have fire anymore.

Water has a very high heat capacity (it can absorb a lot of heat without as great a change in temperature). When you put water on a fire, it absorbs heat and changes into steam. This removes the heat and causes the fire to die.

Interestingly, some types of fires can not be put out by water or will be spread by water. This is most common for liquids that are less dense than water (such as oil) that will float on top of the water layer and will still be able to burn.

Answer 3

Before I answer your question, I am going to address one of your other answers.

nothingtangible's answer is incorrect even though it has a vote as the best. Heat will not cause the separation of hydrogen and oxygen in water. Any explosion in a chimney fire that he is describing comes from the fact that steam/water vapor takes up much more space than liquid water. If there is hot area such as a chimney fire and water is introduced, it has the possibility of flash boiling. This process of creating lots of water vapor/steam will cause pressure inside the chimney. If this pressure causes the chimney ruptures, the once limited amount of air in the chimney is increased from outside air through the rupture. This increased amount of air is what causes the fire to "explode" and not the separation of water into hydrogen and oxygen.

Now onto the answer to your question:
Fire needs three things to burn: fuel, heat, and oxygen.

Water cools most fuels. If the fuel is less dense than water (oils fires), the water will not cool the fuel and thus not put out the fire. In these cases, the oxygen has to be removed with either "foam" or a carbon dioxide extinguisher. There are also materials that burn hot enough to flash boil water and thus water will not work on fires of these substances. One that comes to mind is magnesium metal. It burns hot enough that water will not out it out.

Here is an interesting point. After a fire is put "out" with water, it may reignite. As the fire smolders. it is evaporating the water that was poured on it. If enough of the water evaporates, the fuel source may have enough heat left in it to reignite the fire. This is why fire departments with "hose down" a smoldering fire long after the actual flames are out.

I know my answer is rather long, but I hope it helped.

Answer 4

Water puts out fire by lowering the temperature of the materials burning.

Contrary to what many people believe, the primary function of the water is NOT to smother the fire or to eliminate oxygen. In fact, water is made up of hydrogen, an EXTREMELY flammable gas and oxygen which accelerates flames and increases the ability of materials to burn.

In case of a chimney fire, which burns EXTREMELY hot and fast, pouring water down the chimney can cause an explosion. Due to the extreme heat the hydrogen and oxygen separate so rapidly that they will explode due to the increased combustion of hydrogen in the presence of oxygen.

Answer 5

for a fire you need three things Heat, fuel,and oxygen remove any one of them and the fire goes out. Water cool the fuel lower than the flash point

Answer 6

fire requires oxygen as a gas and water would put it out by suffucating it

Answer 7

Because it has hydrogen in it in large quantity dan oxygen dat's y water puts out fire.

Answer 8

fire needs 3 elements.....fuel. heat source and oxygen
H2O smothers the oxygen,and also cools the heat source

Answer 9

Decreasing temperature.

Answer 10

cold puts out heat.