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Is Light Matter?

Is LIght Matter

  • Total voters
    105
Hokulele said:
(I wasn't trying to argue that ynot's case is correct, simply trying to explain in context why Ziggurat was saying, by ynot's definition, only hydrogen atoms can be considered the smallest unit of matter.)
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I believe that the definition that an atom is the smallest (indivisible) unit of matter is a really old one. After all, that's the one I learned. :blush:

You meddlin' kids with all these atom-splittin' devices are gonna get yers! See what ya get by messin' with tradition? Now ya can't even define matter! When I was a kid, we had the atom and we had to be happy with it. We had no choice!

mummble..mumble..snore
 
ynot said:
Thanks. Are you saying that a hydrogen atom can’t be divided in to another atom, or that it can’t be divided in to anything?
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If you would like my personal opinion, rather than just an expansion of other people's thoughts, I am saying that a hydrogen atom cannot be divided into other atoms, but can be divided into fundamental subatomic particles. For example, free electrons are fundamental subatomic particles. I am not saying that all electrons come from hydrogen atoms, but that they can exist without being bound. This is essentially how electricity gets from the power plant to your house, unbound electrons "moving" through the wires.

http://en.wikipedia.org/wiki/Electron
 
Ziggurat said:
I understand that. But if you want to say that matter is anything made of atoms, well, you're still left with all atoms except hydrogen being divisible into into smaller atoms.
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Sure, but I don’t see that whether atoms are divisible or not is of any consequence to the definition. The definition is that atoms are matter, regardless of whether they can be divided in to other atoms or not. If an atom is divided in to something that is not and atom (subatomic particles), it’s not matter according to the definition.
 
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Slimething said:
I believe that the definition that an atom is the smallest (indivisible) unit of matter is a really old one. After all, that's the one I learned. :blush:

You meddlin' kids with all these atom-splittin' devices are gonna get yers! See what ya get by messin' with tradition? Now ya can't even define matter! When I was a kid, we had the atom and we had to be happy with it. We had no choice!

mummble..mumble..snore
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Thanks - I needed a good laugh :)
 
And we had to walk five miles in the snow to get our atoms too, uphill both ways and those are country miles not your tiny city miles and when we got there we had to wait in line all polite for the atoms....
 
Hokulele said:
I wasn't disagreeing with you (or agreeing for that matter), simply trying to clear up the "hydrogen" comment. By your last statement, "In other words, when an atom is divided, it is no longer matter by that definition", you are running into the difficulty Ziggurat mentioned. Basically, one atom can be split into two other atoms, hence divisible, but still resulting in matter. For example, when an atom of Uranium-235 is split by fission (such as in a bomb), two atoms of Thorium-231 result. You can keep going down the chain until all you have left is hydrogen. So in other words, hydrogen is the only atom that cannot be divided into two other atoms.

http://en.wikipedia.org/wiki/Uranium-235

I hope this clarifies things a bit.
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I think you mean one atom of Thorium-231 and one atom of Helium.
 
I cheated and read through everybody else's comments before I voted. While I can see the validity of the "context" argument by people who obviously know more about physics than I do, I'm still going with "matter has mass, light doesn't, light isn't matter," reasoning I came in with.
 
Amapola said:
A *POLL* to decide whether light is matter or not? Yikes. :boggled:
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It could be like a survey on public knowledge.

I would shudder to think the original poster had a Creationist intent where voting constitutes scientific fact.
 
RecoveringYuppy said:
@Houklele and Wollery


And actually that's describing the alpha decay mode, not fission as in a bomb or reactor.
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Heh. Serves me right for trying to think up an example off the top of my head and not doing my homework. Thanks wollery and RecoveringYuppy for setting the record straight. :)

* Hangs head in shame and goes back to lurk mode *
 
ynot said:
Sure, but I don’t see that whether atoms are divisible or not is of any consequence to the definition. The definition is that atoms are matter, regardless of whether they can be divided in to other atoms or not. If an atom is divided in to something that is not and atom (subatomic particles), it’s not matter according to the definition.
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It's a huge problem. Atoms are divided in everyday life. Cations, for example, are missing an electron. You can easily create cations by dissolving some salt in water. In any context, saying that by dissolving salt, you can destroys matter, is absurd. You might claim that cations are still mostly atoms, but then what about hydrogen cations? It's just a proton, clearly a subatomic particle. We can destroy matter by adding acid to water, or by creating a plasma. This would also leads to the conclusion that the vast majority of mass in the universe is not matter, as it's composed of proton-electron plasmas.

The definition of atoms as the smallest indivisible unit of matter is from Democritus, who was not a scientist (though he had some - in hindsight - good guesses as to how the universe works). Since then, chemists happily adopted atom to mean something similar, the smallest uncharged unit of an element.
 
Dilb said:
It's a huge problem. Atoms are divided in everyday life. Cations, for example, are missing an electron. You can easily create cations by dissolving some salt in water. In any context, saying that by dissolving salt, you can destroys matter, is absurd. You might claim that cations are still mostly atoms, but then what about hydrogen cations? It's just a proton, clearly a subatomic particle. We can destroy matter by adding acid to water, or by creating a plasma. This would also leads to the conclusion that the vast majority of mass in the universe is not matter, as it's composed of proton-electron plasmas.

The definition of atoms as the smallest indivisible unit of matter is from Democritus, who was not a scientist (though he had some - in hindsight - good guesses as to how the universe works). Since then, chemists happily adopted atom to mean something similar, the smallest uncharged unit of an element.
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Thanks - interesting stuff.
 
Voters:

Now that 100 votes have been cast, and there have been 154 posts, I wonder if the debate in this thread has caused anyone to change their mind from their original vote? I still wouldn‘t define light as matter, but now have a better understanding of why some people do.
 
ynot said:
Now that 100 votes have been cast, and there have been 154 posts, I wonder if the debate in this thread has caused anyone to change their mind from their original vote? I still wouldn‘t define light as matter, but now have a better understanding of why some people do.
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Yeah, I'm now a subscriber of the light has no mass school. So, light has momentum but no mass. I am also convinced that once I catch up with all the physicists here, I also will have trouble defining mass.

I think this is a perfect example of science moving past earlier concepts. Or, to put it another way, the more you know, the more you don't know.

Great thread/poll, ynot!
 
trvlr2 said:
Maybe it would be better to think of "matter" as a manifestation of energy?
Then, you could go on to define the cut-off point?
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However, the energy of a photon is defined as E=hf, where h is Planck's constant and f is the frequency, and since, in theory, you can just keep reducing the frequency of the light, you can end up with a photon with an energy of approximately zero.

In theory. ;)
 
Slimething said:
Yeah, I'm now a subscriber of the light has no mass school. So, light has momentum but no mass. I am also convinced that once I catch up with all the physicists here, I also will have trouble defining mass.

I think this is a perfect example of science moving past earlier concepts. Or, to put it another way, the more you know, the more you don't know
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That’s a surprise! I expected that any movement would be towards the affirmative. I think “that lot” put up some good arguments.;)

Great thread/poll, ynot!
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Thanks :)
 
Ziggurat said:
Does the plasma of the sun count as one object? Only in the sense that it's got a reasonably well-defined boundary - inside, everything's all mixing together. But the plasma state of the early universe had no boundary, and the components were not fixed in place, so I don't think the "one object" picture makes much sense.
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Is the Sun the best analogy for the quark-gluon plasma? I tend to think of a neutron star as one atom. Did the quark-gluon plasma of the nascent universe have a lot of unoccupied states or few? (it's still mostly semantics though)
 
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