How does water extinguish fire?

In summary, water extinguishes fire by cutting off access to oxygen and cooling the fuel to below its combustion temperature. This is because water has a high specific heat, meaning it takes a lot of energy to increase its temperature. Heat is also a necessary component for fire, and when water cools the fuel below its combustion temperature, it is effectively removing that heat source. This is also why water is commonly used as a cooling agent in nuclear reactors.
  • #1
MR
16
0
How does water extinguish fire? My 5-year-old brother asked me, and now I'm really curious.
 
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  • #2
Fire needs two things: oxygen and fuel.

Water cuts off access to oxygen, and cools the fuel to below combustion temperature.
 
  • #3
OK, now I'm feeling REALLY ignorant...
What's combustion temperature?
Also, I've heard a number of times of using water as a cooling agent (especially in nuclear reactors), but why does water cool things down so well?
Thanks!
 
  • #4
MR said:
Also, I've heard a number of times of using water as a cooling agent (especially in nuclear reactors), but why does water cool things down so well?
Thanks!
water has a high specific heat, meaning it takes a lot of energy/heat to increase the temperature of 1 gram of water by 1 degree Celcius
 
  • #5
imabug said:
Fire needs two things: oxygen and fuel.

Water cuts off access to oxygen, and cools the fuel to below combustion temperature.
Make that 3 things: oxygen, fuel, and heat. Your description has all 3.

MR, when you strike a match, you are using friction to increase the temperature of the phosphorous on the match head above its ignition temperature - the temperature at which it starts to burn. After it starts to burn, it expends more energy than is needed to keep the fuel burning - so it stays lit.

Welcome aboard!
 
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  • #6
russ_watters said:
Make that 3 things: oxygen, fuel, and heat. Your description has all 3.
right, heat. i always make that mistake. I figure if you're talking fire, heat's pretty much a given.
 
  • #7
Thanks, people...This is so cool!
 

FAQ: How does water extinguish fire?

How does water extinguish fire?

Water extinguishes fire through a process called cooling. When water is sprayed onto a fire, it absorbs heat from the fire and lowers the temperature below the point where the fire can sustain itself. This stops the fire from spreading and eventually extinguishes it.

What is the role of oxygen in fire extinguishment with water?

Oxygen is a key factor in fire extinguishment with water. When water is sprayed onto a fire, it creates a barrier between the fuel (the material that is burning) and the oxygen in the air. Without oxygen, the fire cannot continue to burn and is extinguished.

Can any type of water be used to extinguish fire?

No, not all types of water can be used to extinguish fire. The most effective type of water for fire extinguishment is potable water, which is safe for consumption. Other types of water, such as salt water or contaminated water, may not be as effective and could even make the fire worse.

Does the temperature of the water matter when extinguishing fire?

Yes, the temperature of the water can affect its effectiveness in extinguishing fire. Cold water is generally more effective because it can absorb heat from the fire more quickly. However, using hot water can also be effective as long as it is applied in large quantities.

Can water be used to extinguish all types of fires?

No, water is not effective for all types of fires. It is most effective for Class A fires, which involve ordinary combustible materials such as wood, paper, or cloth. Water can actually make other types of fires, such as grease or electrical fires, worse. It is important to use the correct type of extinguishing agent for each type of fire.

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