How does water extinguish fire?

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SUMMARY

Water extinguishes fire by cutting off access to oxygen and cooling the fuel below its combustion temperature. Fire requires three elements: oxygen, fuel, and heat. Water's high specific heat capacity allows it to absorb significant amounts of heat, making it an effective cooling agent. This principle is also utilized in nuclear reactors where water is used to manage heat levels.

PREREQUISITES
  • Understanding of the fire triangle: oxygen, fuel, and heat
  • Knowledge of combustion temperature concepts
  • Familiarity with specific heat capacity
  • Basic principles of thermodynamics
NEXT STEPS
  • Research the fire triangle and its implications in fire safety
  • Learn about combustion temperature and its significance in fire behavior
  • Explore the concept of specific heat capacity and its applications
  • Investigate the role of water as a cooling agent in nuclear reactors
USEFUL FOR

Students, educators, fire safety professionals, and anyone interested in the science of fire and heat management.

MR
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How does water extinguish fire? My 5-year-old brother asked me, and now I'm really curious.
 
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Fire needs two things: oxygen and fuel.

Water cuts off access to oxygen, and cools the fuel to below combustion temperature.
 
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!
 
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 celsius
 
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!
 
Last edited:
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.
 
Thanks, people...This is so cool!
 

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