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When I was a volunteer firefighter circa 1999 we were forced to learn the definition of fire that would appease a lawyer / court in case we got subpoenaed. App

When I was a volunteer firefighter circa 1999 we were forced to learn the definition of fire that would appease a lawyer / court in case we got subpoenaed. Apparently somewhere else there had been an arson fire and the fire chief was on the stand and the defense asked him what fire was and all he could come up with was "it's hot" or something similar. I don't know if it caused the case to be won or lost but our Chiefs decided we wouldn't chance the embarrassment. I'll now forever remember that "fire is the rapid oxidation of a combustible material resulting in the release of energy in the form of heat and light". Still waiting on that subpoena and my chance to put this to good use. Or at least trivia night or something...

deleted 10y ago
[deleted]
sandworm101 10y ago
Heat and radiation, some of which is called light. Infrared energy isn't really heat, nor is it generally called light as it isnt visible. Similarly, many chemical fires release substantial amounts of UV, but i doubt anyone would see much of it in an emergency through all the smoke and ir. Think rocket fuels.
- nsxwolf 10y ago
  I've frequently seen "light" used to refer to the entire electromagnetic spectrum in physics discussions.
  - swift 10y ago
    Yeah, I typically hear visible light referred to as, well, "visible light". It may depend on the whims of the particular textbooks and professors you learned from, but in my physics classes we always used "light" to refer to the entire electromagnetic spectrum, and I only realized relatively late in life that some people don't use the terminology that way.
    - nsxwolf 10y ago
      Plus I like to think of all light as being "visible" to some material or apparatus. Our eyes just happen to be tuned to a particular part of the spectrum. You don't even have to look very far to find other animals that can see wavelengths we can't, like ultraviolet. Radio antennas "see" radio waves, film emulsions and CCDs "see" X-rays, etc. Also with radio we talk about different materials being "transparent" to one wavelength or another.
      - harperlee 10y ago
        It's amazing to think that, for the wifi module, the rest of the laptop is more or less transparent, as in a crystal case.
      - hermitdev 10y ago
        If you ever want to have some fun flying, carry some lead crystal in your carry on luggage. A number of years back, I was visiting my parents for Christmas, and they gave me a set of lead crystal tumblers. Apparently due mostly to the lead and partly to the cut of the tumblers, they appeared as hand grenades on the luggage scanner. The look of absolute puzzlement on the TSA agents' faces were priceless. They could not reconcile what they saw on their scanners with what they held in their hand, even when I explained what it was. I've had similar experiences flying with lead crystal ornaments. Which, while always a gift, I never have wrapped while I'm flying, because I know, inevitably I'd need to open it, anyway.
        nsxwolf 10y ago
        That's great! I wouldn't have helped them! I would have just said "Those are drinking glasses."
  - sandworm101 10y ago
    And ive seen oxygen and argon called "metals" (in stars). Each field has thier own terms.
    - zodiac 10y ago
      Well the metallic state has a pretty precise definition, presumably the oxygen in stars exists in that state. (Whereas oxygen in air does not)
      - MereInterest 10y ago
        Nope, not at all. In astrophysics, "metal" refers to any element heavier than helium, regardless of oxidation state. It is a useful definition, because only hydrogen and helium were present from the big bang. The metallicity of a star then determines the age of the nebula that formed it. More metals (in the astrophysical sense) means that other stars had to exist, make heavier elements, and explode prior to that stars birth. It's a different definition, but it is quite useful in the field.
      - sandworm101 10y ago
        Again, "the metalic state" is for a different field. Same root words, different definitions and uses depending on context.
- johncolanduoni 10y ago
  Physicists (even those who work in optics) routinely use light to mean anything on the EM spectrum, so I'm not sure where you're getting the "right" technical definition.
  - sandworm101 10y ago
    Because this is a firefighter's definition for use in a courtroom. It isnt about physics but the realities of flame. In the real world there are things like "invisible fire", common at racetracks during the day, that need to be accounted for. Tge physics of stellar astronomy do not.
    - johncolanduoni 10y ago
      "nor is it generally called light" sure doesn't sound like it's talking about the specific, legally relevant definition used by firefighters. Also most physicists whose work is centered around EM radiation aren't astrophysicists and plenty of them work specifically with visible light, so your patronization is off the mark.
      - sandworm101 10y ago
        Most physicists also do not have much experiance with uncontrolled fire. To say that all fires produce light will be confusing if trying to explain non-visible flames to a lay jury.
- kgwgk 10y ago
  If you want to be pedant, the energy from the combustion is released in the form of heat (some of which is called radiation (some of which is called light)).
  - bandrami 10y ago
    Eh. Heat is energy with certain entropic characteristics. Electromagnetic radiation carries that energy, but is not itself the energy.
    - kgwgk 10y ago
      I was paraphrasing a previous comment. Heat is the energy transferred between systems and that's how I interpreted the "energy is released in the form of" in the original comment. I'm not sure what is your point. Do you think that saying that the "energy is released in the form of heat and radiation" is better? To me that seems like saying "energy is released in the form of heat (i.e. energy transferred) and radiation (i.e. one the transfer mechanisms)". Do you like "heat (some of which is transferred through radiation (some of which is called light))" better?
jschwartzi 10y ago
That reminds me of how one of my Physics instructors made us memorize Archimedes' principle: The buoyant force on an object is equal to the weight of the displaced fluid.
dnautics 10y ago
to be honest I don't think that this article answers the question 'what is fire' but more 'what exactly is the flame of a fire'
- hvidgaard 10y ago
  Isn't the flames the fire? If you only have embers, you wouldn't call it a fire.
  - richmarr 10y ago
    > If you only have embers, you wouldn't call it a fire. Well, you might https://en.wikipedia.org/wiki/Coal_seam_fire https://en.wikipedia.org/wiki/Coal_seam_fire
  - marcosdumay 10y ago
    Can you have a flame without the fire? You certainly can have something very similar. Personally, I think those names are all confusing and ill-defined. Does "fire" imply in sustainability? Does it need to be combustion? Does it even have to be chemical?
  - dnautics 10y ago
    You can certainly have fires without flames. Particularly notorious is hydrogen, which burns cleanly with no flame (just heat ripples). This is one of the major challenges for hydrogen fueled vehicles:. First responders need to be aware that the combustion properties for a hydrogen vehicle are different and could be deceptively more dangerous than their trained instinct.
- couchand 10y ago
  There is mention early of fire in the technical sense, before moving on to considering flame in greater detail. For my part, on reading the headline I expected and hoped that the discussion was about flame. Naming things is hard.
jventura 10y ago
I was also a volunteer firefighter around those years as well but we had to learn the definition of fire using the fire triangle [0]. It is a simple model to reason about fire and how to extinguish it: just remove any of the three components (oxygen, heat or fuel). [0] https://en.wikipedia.org/wiki/Fire_triangle https://en.wikipedia.org/wiki/Fire_triangle
- stoolpigeon 10y ago
  That's what I was taught in the Navy for my various firefighting courses - along with types of fires, how to handle the various types, and so on. Very useful stuff.
- OscarCunningham 10y ago
  Halon fire extinguishers are interesting in that they disrupt the chemical reaction of the fire directly. There's still fuel, heat and oxygen, but they just don't react.
  - couchand 10y ago
    And that is a great example of Spolsky's Law of Leaky Abstractions.
    - harperlee 10y ago
      Although to be fair the link that was provided also adds the "chain reaction" in a fire tetrahedron.
  - leetrout 10y ago
    And fun/scary fact- they DON'T work on lithium ion batteries... I think it might slow it down but it doesn't stop them. https://batterybro.com/blogs/18650-wholesale-battery-reviews/19673027-plane-safety-systems-are-confirmed-to-not-stop-lithium-ion-battery-fires https://batterybro.com/blogs/18650-wholesale-battery-reviews...
  - hermitdev 10y ago

deleted 10y ago

[deleted]

sandworm101 10y ago

Heat and radiation, some of which is called light. Infrared energy isn't really heat, nor is it generally called light as it isnt visible. Similarly, many chemical fires release substantial amounts of UV, but i doubt anyone would see much of it in an emergency through all the smoke and ir. Think rocket fuels.

nsxwolf 10y ago
I've frequently seen "light" used to refer to the entire electromagnetic spectrum in physics discussions.
- swift 10y ago
  Yeah, I typically hear visible light referred to as, well, "visible light". It may depend on the whims of the particular textbooks and professors you learned from, but in my physics classes we always used "light" to refer to the entire electromagnetic spectrum, and I only realized relatively late in life that some people don't use the terminology that way.
  - nsxwolf 10y ago
    Plus I like to think of all light as being "visible" to some material or apparatus. Our eyes just happen to be tuned to a particular part of the spectrum. You don't even have to look very far to find other animals that can see wavelengths we can't, like ultraviolet. Radio antennas "see" radio waves, film emulsions and CCDs "see" X-rays, etc. Also with radio we talk about different materials being "transparent" to one wavelength or another.
    - harperlee 10y ago
      It's amazing to think that, for the wifi module, the rest of the laptop is more or less transparent, as in a crystal case.
    - hermitdev 10y ago
      If you ever want to have some fun flying, carry some lead crystal in your carry on luggage. A number of years back, I was visiting my parents for Christmas, and they gave me a set of lead crystal tumblers. Apparently due mostly to the lead and partly to the cut of the tumblers, they appeared as hand grenades on the luggage scanner. The look of absolute puzzlement on the TSA agents' faces were priceless. They could not reconcile what they saw on their scanners with what they held in their hand, even when I explained what it was. I've had similar experiences flying with lead crystal ornaments. Which, while always a gift, I never have wrapped while I'm flying, because I know, inevitably I'd need to open it, anyway.
      - nsxwolf 10y ago
        That's great! I wouldn't have helped them! I would have just said "Those are drinking glasses."
- sandworm101 10y ago
  And ive seen oxygen and argon called "metals" (in stars). Each field has thier own terms.
  - zodiac 10y ago
    Well the metallic state has a pretty precise definition, presumably the oxygen in stars exists in that state. (Whereas oxygen in air does not)
    - MereInterest 10y ago
      Nope, not at all. In astrophysics, "metal" refers to any element heavier than helium, regardless of oxidation state. It is a useful definition, because only hydrogen and helium were present from the big bang. The metallicity of a star then determines the age of the nebula that formed it. More metals (in the astrophysical sense) means that other stars had to exist, make heavier elements, and explode prior to that stars birth. It's a different definition, but it is quite useful in the field.
    - sandworm101 10y ago
      Again, "the metalic state" is for a different field. Same root words, different definitions and uses depending on context.
johncolanduoni 10y ago
Physicists (even those who work in optics) routinely use light to mean anything on the EM spectrum, so I'm not sure where you're getting the "right" technical definition.
- sandworm101 10y ago
  Because this is a firefighter's definition for use in a courtroom. It isnt about physics but the realities of flame. In the real world there are things like "invisible fire", common at racetracks during the day, that need to be accounted for. Tge physics of stellar astronomy do not.
  - johncolanduoni 10y ago
    "nor is it generally called light" sure doesn't sound like it's talking about the specific, legally relevant definition used by firefighters. Also most physicists whose work is centered around EM radiation aren't astrophysicists and plenty of them work specifically with visible light, so your patronization is off the mark.
    - sandworm101 10y ago
      Most physicists also do not have much experiance with uncontrolled fire. To say that all fires produce light will be confusing if trying to explain non-visible flames to a lay jury.
kgwgk 10y ago
If you want to be pedant, the energy from the combustion is released in the form of heat (some of which is called radiation (some of which is called light)).
- bandrami 10y ago
  Eh. Heat is energy with certain entropic characteristics. Electromagnetic radiation carries that energy, but is not itself the energy.
  - kgwgk 10y ago
    I was paraphrasing a previous comment. Heat is the energy transferred between systems and that's how I interpreted the "energy is released in the form of" in the original comment. I'm not sure what is your point. Do you think that saying that the "energy is released in the form of heat and radiation" is better? To me that seems like saying "energy is released in the form of heat (i.e. energy transferred) and radiation (i.e. one the transfer mechanisms)". Do you like "heat (some of which is transferred through radiation (some of which is called light))" better?

jschwartzi 10y ago

That reminds me of how one of my Physics instructors made us memorize Archimedes' principle: The buoyant force on an object is equal to the weight of the displaced fluid.

dnautics 10y ago

to be honest I don't think that this article answers the question 'what is fire' but more 'what exactly is the flame of a fire'

hvidgaard 10y ago
Isn't the flames the fire? If you only have embers, you wouldn't call it a fire.
- richmarr 10y ago
  > If you only have embers, you wouldn't call it a fire. Well, you might https://en.wikipedia.org/wiki/Coal_seam_fire https://en.wikipedia.org/wiki/Coal_seam_fire
- marcosdumay 10y ago
  Can you have a flame without the fire? You certainly can have something very similar. Personally, I think those names are all confusing and ill-defined. Does "fire" imply in sustainability? Does it need to be combustion? Does it even have to be chemical?
- dnautics 10y ago
  You can certainly have fires without flames. Particularly notorious is hydrogen, which burns cleanly with no flame (just heat ripples). This is one of the major challenges for hydrogen fueled vehicles:. First responders need to be aware that the combustion properties for a hydrogen vehicle are different and could be deceptively more dangerous than their trained instinct.
couchand 10y ago
There is mention early of fire in the technical sense, before moving on to considering flame in greater detail. For my part, on reading the headline I expected and hoped that the discussion was about flame. Naming things is hard.

jventura 10y ago

I was also a volunteer firefighter around those years as well but we had to learn the definition of fire using the fire triangle [0]. It is a simple model to reason about fire and how to extinguish it: just remove any of the three components (oxygen, heat or fuel). [0] https://en.wikipedia.org/wiki/Fire_triangle https://en.wikipedia.org/wiki/Fire_triangle

stoolpigeon 10y ago
That's what I was taught in the Navy for my various firefighting courses - along with types of fires, how to handle the various types, and so on. Very useful stuff.
OscarCunningham 10y ago
Halon fire extinguishers are interesting in that they disrupt the chemical reaction of the fire directly. There's still fuel, heat and oxygen, but they just don't react.
- couchand 10y ago
  And that is a great example of Spolsky's Law of Leaky Abstractions.
  - harperlee 10y ago
    Although to be fair the link that was provided also adds the "chain reaction" in a fire tetrahedron.
- leetrout 10y ago
  And fun/scary fact- they DON'T work on lithium ion batteries... I think it might slow it down but it doesn't stop them. https://batterybro.com/blogs/18650-wholesale-battery-reviews/19673027-plane-safety-systems-are-confirmed-to-not-stop-lithium-ion-battery-fires https://batterybro.com/blogs/18650-wholesale-battery-reviews...
- hermitdev 10y ago