Good morning John!  

I have been a person who professionally talks about science for - uh - years now.  It's a wonderful job.  And I love almost every question I get.  

There are two kinds of questions that I don't love to get.  

One is questions that I've answered a bunch of times before, and I'm like, 'alright, somebody else handle this one.'  

And second is questions that seem like they should just be very easy to answer, but they. .  . aren't.  

And. . . they're. . . they just sit there, and I don't answer them, and then I'm like 'UUUGHH! Why is this so hard?'  

And no question in this second category is more common than the title of this video  "what state of matter is fire?"  

If you ask this question to Google, you get all wrong answers.  

Why are we doing this to ourselves‽  What is so hard here‽  

Well, we are doing this to ourselves because it is very, very, not simple.  

Now, matter really does mostly exist in a few discreet states.  And that's literally because of how the atoms and molecules are interacting with each other.  

But i think what mostly sticks with us isn't like, thinking about, in terms of particles, it's just sort of the qualities.  

So, a solid keeps its shape.  A liquid keeps its volume, but its shape can change.  And then a gas - its volume and shape can change.  

And if you just take that, and you put it on fire, you're like "well, none of that's true".  

So let me, instead, just answer this question with a question.  

What state of matter is a waterfall?

Now, you're going to think to yourself 'Hank, that's a liquid'.  

But, no, the water in the waterfall is a liquid, but the waterfall is not matter.  It is a process caused by a bunch of liquids, and gasses, and solids, in a specific situation.  A waterfall does not have a state of matter because a waterfall isn't matter.  It's a process.  

Now, you can look at it, and you can say 'that cliff  is made of rock, and the water is a liquid, and the air that's sort of tossing up those water droplets, that's a gas.  

So I can kinda answer the question 'what state of matter is a waterfall?'

It's a bunch of different states of matter.  And so the natural thing to do is to do this with fire - just label the constituents.

And this is why water is harder than a waterfall - because the molecules in a fire - unlike the molecules in a waterfall - are  undergoing rapid chemical reactions.  

And while those chemicals are still made of matter, they are reacting.  They do not have a state of matter because their electrons are jumping from atom to atom, molecules are rearranging, and in the space between one chemical and another, we don't really know what things are, because we can't put them in bottles.  

We can, however, stop them.  

I'm gonna do that for you right now.  

I'm gonna pause the chemical reaction while it is going on.  

If I pass my spoon through my fire, what I get is soot.  And this is why a lot of people say that the state of matter of fire is a solid.  

What is happening in this fire is that wax is evaporating, and then it is combusting.  It's burning.  

In the process of that combustion, lots of different, weird chemicals are formed.  And they are all turned into these little, tiny particles that, in the flame, while they are undergoing their own chemical reactions, glow with heat.  

As they continue through the flame, they continue to react, and at the end of this process, you don't have this solid any more.  

But in there, most of what you see in the fire is solid pieces of soot glowing.   But there's also a component of the flame, the blue part, to be exact, that is NOT caused by soot particles glowing.  This is excited atoms of gas emitting light as as well.  

But also, because there are so many reactions happening so quickly in combustion, the matter in the flame isn't behaving like how we think mater behaves.  Like, because it's in the midst of a chemical reaction.  

So those atoms, and electrons, and ions, and molecules and inbetween-y molecules, they. . .  kind of aren't any state of matter.  

And maybe we will understand all of that better some day.

But really, it's just a place where these usually quite hard lines between things kind of breaks down.  

For me though, there's a real answer that's so much simpler than this: fire does not have a state of matter, because fire is not matter.  

Fire is a process.  

John, I'll see you on Wednesday.  Tue. . . Wednesday?  Tuesday.  

By the way, this year's Project for Awesome calendar is now available, we do it a little before the Project for Awesome so you can actually have it.  

This year's calendar celebrates a lot of the history with Nerdfighteria, with different images from, kind of, different eras of this wonderful, bizarre thing, that also is very difficult to describe.