Can there bee too cold to set on fire?
Fire
Eh. What do you mean? I think you'll need some good material to burn, and oxygen. I don't think it can be too cold, but I'm not a scientist. Anyone here knows something about that. I'm actually curious aswell 
You know eskimo's make fire's too! So I think it never can be too cold to make a fire
Yes, but those are under normal circumstances on earth. What if you would do it under controlled circumstances and make it very cold on purpose. I mean, we are talking about very very low temperatures here.
Well... To start a fire you need heat, fuel, and oxygen. I'm not a scientist, but here's my hypothesis on the subject (however I unfortunately do not have the materials to test this hypothesis): you will be able to light a fire at any possible temperature as long as those three elements exist. Heat will always exist because getting to absolute zero is impossible. Besides, almost anytime energy is used heat is given off as a byproduct. Fuel can be put into the equation at will. As long as all the required materials are there, I see no reason why you shouldn't be able to light a fire when it's cold...
| Afaceinthematrix wrote: |
| Heat will always exist because getting to absolute zero is impossible. |
It requires a certain amount of heat though, based on the material.
Even at extremely cold temperatures though, making the spark that starts the fire defeats the purpose of conducting the test in the cold.
Normally flammable materials could be made inflammable by extreme cold, by making the energy needed to bring them to burning temperature too high for the burning of that same material to produce: that way, a fire could not spread.
flash point is the magic word.
for each material there is a certain °C/°F/°K-value and below it is impossible to make it burn.
for eyample: fuel can not ignite below -21°C
for each material there is a certain °C/°F/°K-value and below it is impossible to make it burn.
for eyample: fuel can not ignite below -21°C
| Quote: |
| Normally flammable materials could be made inflammable by extreme cold, by making the energy needed to bring them to burning temperature too high for the burning of that same material to produce: that way, a fire could not spread. |
This is false...extreme colds do not make things imflammable, the substances volume and mass make it so.
All things can be ignited as long as the source is strong enough to reach the pre-mentioned burning temperature, as for creating the actual flame in a cold atmosphere It can always be done as long as there is oxygen. The cold will help put it out but the fire can still be made.
** There is no "lets make this colder" device to make things imflammable the object that is made has a burning point, thats it.
| StarlightStudios wrote: | ||
This is false...extreme colds do not make things imflammable, the substances volume and mass make it so. All things can be ignited as long as the source is strong enough to reach the pre-mentioned burning temperature, as for creating the actual flame in a cold atmosphere It can always be done as long as there is oxygen. The cold will help put it out but the fire can still be made. ** There is no "lets make this colder" device to make things imflammable the object that is made has a burning point, thats it. |
Well, the reason a material continues to burn and the fire spreads is because when part of the material burns, it makes the part next to it rise up to the ignition temperature. If the adjacent part of the material was cold enough, the part next to it burning might not produce enough heat to raise it to ignition temperature, so the fire wouldn't spread. For most materials, that kind of cold could only be found in a laboratory though. The normal range of temperatures on Earth won't affect the flammability of various materials very much, I think.
To see the effects of this, I think you would need to find something with a (relatively) high ignition temperature that doesn't produce much heat when it burns.
| ocalhoun wrote: |
| To see the effects of this, I think you would need to find something with a (relatively) high ignition temperature that doesn't produce much heat when it burns. |
(Actually, what you would need is something that is extremely conductive and a heat sink. What would happen is when part A burns and attempts to transfer heat to the adjacent part B to ignite it, that heat would travel right through part B into part C, then D, then E, etc. until it gets dumped into the heat sink.
If all you have is a situation with high ignition temperature but slow, cool burning... but poor conductivity... you would still get the burn spreading. What would happen is part A would have a lot of heat energy to begin with (in order to ignite), and then it would be producing more - even if not much - via burning. This energy would then be passed to part B... but because the material has poor thermal conductivity, the heat has nowhere to go, so it builds in part B until part B ignites. And again, now part B has a ton of energy and is producing more as it burns... which has nowhere to go but part C, etc.
The key is not ignition temperature, or how fast it produces heat as it burns - the key is how fast the material can ditch excess heat: the thermal conductivity.)
Basically you need Heat, Oxygen and some sort of fuel...
Than you can start a fire
Than you can start a fire
michaeljscott93 wrote:
Though I think I understand what the orginal poster is trying to say.
We DO need those mentioned above but we need to consider the situaion/surrounding factors.
Hence, kvrss' responce:
| Quote: |
| Basically you need Heat, Oxygen and some sort of fuel...
Than you can start a fire |
Though I think I understand what the orginal poster is trying to say.
We DO need those mentioned above but we need to consider the situaion/surrounding factors.
Hence, kvrss' responce:
| Quote: |
| flash point is the magic word.
for each material there is a certain °C/°F/°K-value and below it is impossible to make it burn. for eyample: fuel can not ignite below -21°C |
| Indi wrote: |
|
What would happen is part A would have a lot of heat energy to begin with (in order to ignite), |
Ah, I forgot that the energy used to start the fire would still be there.
It is possible to get too cold for the fire to be sustainable. Once the source of the flame source is gone, if it is cold enough, material would act flame retardant.
I don't know at what temperatures that would occur. I would suppose the opposite to be the case where flame retardant materials are no longer flame retardant at certain higher temperatures.
I don't know at what temperatures that would occur. I would suppose the opposite to be the case where flame retardant materials are no longer flame retardant at certain higher temperatures.
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