The atoms like each other to different degrees. Oxygen, for instance, in the
air, would like to be next to carbon, and if they get near each other, they snap
together. If they're not too close, though, they repel, and they go apart. So
they don't know that they could snap together. It's just as if you had a ball
that was trying to climb a hill, and there was a hole it could go into, like a
volcano hole, a deep one. It's rolling along. It doesn't go down in the deep
hole, because it starts to climb the hill and then rolls away again. But if you
made it go fast enough, it'll fall into the hole. And so if you have something
like wood and oxygen, there's carbon in the wood from the tree. And the oxygen
comes and hits it, carbon, but not hard enough. It just goes away again. The air
is always — nothing's happening. If you can get it faster, by heating it up
somehow, somewhere, somehow, get it started, a few of them come fast, they go
over the top, so to speak. They come close enough to the carbon and snap in. And
that gives a lot of jiggly motion, which might hit some other atoms, making
those go faster, so they can climb up and bump against other carbon atoms and
they jiggle and they make others jiggle, and you get a terrible catastrophe,
which is one after the other all these things are going faster and faster, and
snapping in, and the whole thing is changing. That catastrophe is a fire. It's
just a way of looking at it. And these things are happening. The perpetual...
Once it gets started, it keeps on going. The heat makes the other atoms capable
of reaching, to make more heat to make other atoms and so on. So this terrible
snapping is producing a lot of jiggling. And if I put... With all that activity
of the atoms there, and I put a cup of coffee over that mess of wood that's
doing this, it's going to get a lot of jiggling. So that's what the heat of the
fire is. Then, of course, you see, this is what happens when you start to think.
You just go on and on. You wonder where — how did it get started? Why is it that
the wood's been sitting around all this time, with the oxygen all this time, and
it didn't do this earlier or something? Where did I get this from? Well, it came
from a tree. And the substance of the tree is carbon. Where did that come from?
That comes from the air. It's carbon dioxide from the air. People look at trees
and they think it comes out of the ground, that plants grow out of the ground.
But if you ask where the substance comes from, you find out — where do they come
from? The trees come out of the air? They surely come out of the — no. They come
out of the air. The carbon dioxide in the air goes into the tree and it changes
it, kicking out the oxygen. And pushing the oxygen away from the carbon, and
leaving the carbon substance with water. Water comes out of the ground, you see.
Only — how did it get in there? It came out of the air, didn't it? It came down
from the sky. So, in fact, most of the tree, almost all of the tree, is out of
the ground. I'm sorry. It's out of the air. There's a little bit from the
ground. Some minerals and so forth. Now, of course I told you the oxygen — we
know the oxygen and carbon stick together very tight. How is it the tree is so
smart, as to manage to take the carbon dioxide, which is the carbon and oxygen
nicely combined, and undo that so easy? Ah, life. Life has some mysterious
force? No, the sun is shining. And it's the sunlight that comes down and knocks
this oxygen away from the carbon. So it takes sunlight to get the plant to work.
Документальный фильм "Richard Feynman 'Fun to Imagine' 2: Fire"
