## anonymous one year ago What is Fire??? (Which State does it belongs to?)

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1. arindameducationusc

@harishk Fire is a process in which substances combine chemically with oxygen from the air and typically give out bright light, heat, and smoke; combustion or burning. What is the state of matter of flame? Fire is an oxidizing chemical reaction that releases heat and light. The actual flames that you see moving and glowing when something is burning are simply gas that is still reacting and giving off light.

2. anonymous

Also as there is abundance of oxygen the chemical reactions induced by fire is virally continuous so long as there are sufficient reactants

3. anonymous

So you can see whenever fire can't burn there is a lack of chemical materials with which to burn them if any of them is missing

4. anonymous

I kind of heard somebody saying it is a Plasma matter... the 4th state of matter..

5. anonymous

the flame can indeed be described as a low temperature plasma.

6. anonymous

Define Plasma... in own words...

7. anonymous

8. anonymous

since the name @PlasmaFuzer iam pretty sure it got that right over plasma.. and as according to you, plasma is actually a state of ionized gas, which is not light.. right...???

9. anonymous

Sorry I have been busy these last few days, and haven't had a chance to reply. Yes plasma is not light. Light consists of photons that can be given off by many different phenomenon. If you observe plasma in nature or on earth, it will usually be emitting a lot of light. This is because plasma is not the preferred (read lowest energy) state in which matter exists. To create a plasma, it takes input energy of some form to produce an ionization of the material (usually a gas of but not always.... google solid state plasma if curious); however even with input energy the atoms within the plasma don't just become ionized and stay that way. There is a continual process of electrons being knocked off of neutral atoms and recombining with ions and vice versa (both seeking at all times to lower their respective energy's) throughout the plasma. However this continuous cycle of ionizing and recombining generates lots and lots of photons which correspond to the energy required for an electron to neutralize an atom. Put simply, when an electron with just the right value of energy strikes the ion the excess kinetic energy the photon had is given up as an emitted photon. This photon's wavelength is tied very simply to this energy difference as follows: $(free\ electron\ energy)-(bound\ electron\ energy)=\Delta E=h \nu = \frac{hc}{\lambda}$ Where delta E is the energy given up by the electron to neutralize the ion, h is Planck's constant, c the speed of light, and nu and lambda are the emitted photon's frequency and wavelength. Quite frequently, these can correspond to the frequency/wavelength of visible light and thus we can perceive them with our eyes, and if they are within the visible light spectrum then then frequency/wavelength will determine the color we perceive. Now I have only outlined one mechanism by which light can be generated by plasmas and I have broad stroked it ignoring some more subtle details, though I hinted at it since that "just right energy" for the electron comes down to quantum mechanics. So keep in mind that this is by no means the only way light can be generated here and the mechanism can often be very complicated. Nevertheless this is a common fairly straightforward process within plasma and is fairly easy to explain so hopefully its food for thought and drives you to want to read more about it. If you would like to read more about the specific way in which fire gives off light, and the color that light takes, then I direct you here: http://www.physlink.com/Education/AskExperts/ae569.cfm Note there is a difference between exciting electrons to higher energy levels and fully ionizing electrons. In plasmas, generally speaking, most atoms are ionized most of the time; whereas in fire, only a small portion of atoms are actually ionized the rest have just been excited by the energy of the chemical reaction. The radiation I mentioned in my previous post is generated by this process of electrons emitting photons in order to lower their energy and drop to a lower energy level. So again, this is why fire is not considered a plasma.