What exactly is fire? Is it purely energy? What state of matter is it? Can it be ionized? Can it be affected by magnetism? Gravity?

Confused,..well first think read the theory and then check for yourselves...

The correct definition needed to understand fire's properties is:

"Fire is the rapid combination of oxygen with fuel in the presence of heat, typically characterized by flame, a body of incandescent gas that contains and sustains the reaction and emits light and heat."

1) Rapid combination of oxygen with fuel in the presence of heat.Oxygen, fuel, and heat are the essential ingredients of fire. 

(2) Typically characterized by flame.  "Typically" allows mus to sidestep the issue of apparently nonflaming fires, like you get with burning charcoal. But charcoal fires do create flame--we just can't see it due to the lack of impurities or incompletely burned fuel in the plume. (we can't see a fuel fire at an Indy or CART race either, because the cars run on clean-burning methanol.) 

(3) Body of incandescent gas. Flame defined. Most encyclopedia and dictionary definitions blow past this entirely, allowing persons such as yourself to imagine that fire is "pure energy" or similar nonsense. We say "body" because the gas has a characteristic structure and composition. We say "incandescent" because (a) it sounds scientific, (b) it means "luminous with intense heat," precisely what we are attempting to convey. 

4) Contains and sustains the reaction. Flame isn't just the result of fire; it is the fire. What's more, without the flame's heat the fire would go out.

(5) Emits light and heat. Duh. However, we mustn't overlook the obvious.



 

Now to your other questions:

Is fire purely energy? Clearly not. The dancing flames are glowing gas--your suspicions confirmed.







                               

Can fire be ionized? Is it affected by magnetism? Not so's you'd notice. You're thinking of plasma, which is ionized (and thus electromagnetically reactive) gas, often described as the fourth state of matter. You see it in welding arcs, lightning bolts, and the sun. Ordinary fire isn't plasma.





Is fire affected by gravity? Of course--gas has mass. Flame is shaped by convection, a function of gravity (hot air rises). In low- or zero-G environments, fire looks way different: a candle flame on the space shuttle isn't yellow and tapered but blue and nearly spherical.







 





 

So there you have it. One step closer to a better world.Rates and comments awaited....