States of Matter

[rahuldandekar]

Why are there three states of matter? Why are there definite boundaries separating them? Why doesn't matter just thin or thicken gradually, instead of schanging drastically at melting and boiling points?

[antoniseb]

Originally posted by rahuldandekar@Jan 12 2005, 02:06 PM
Why are there three states of matter? Why are there definite boundaries separating them?
There are more than three, but there's only three that we see in day to day life.

The reason there are boundaries [at least at low pressure] is that there are certain temperatures where the vibrational energy of the molecules making up the matter is either above or below the energy that cohesively binds the molecules to the other molecules. At sufficiently high pressure you can't really tell liquid from gas.

Other states of matter include Bose-Einstein Condensate, Plasma, White-Dwarf Degenerate Matter, Neutron Star Matter, Quark Soup, and perhaps others as we learn more about the behavior of extreme matter.

[StarLab]

Remember the four forces? At certain temperatures, these forces may weaken in some way, or form interesting combinations with each other. We merely live in a spacetime whence solids, liquids and gasses are the norm.

Of course there are other states of matter, but we can only truly exist in three of them...

You see, it's not matter that changes...it's the binding forces which change. These forces can either separate or squash matter.


Rahul, If you haven't already, you should take a chemistry class.
Anton, is there a site for laypeople with info on all the different forms of matter discovered (the stuff on your list as well as anything else) and their properties?

[antoniseb]

Originally posted by StarLab@Jan 12 2005, 06:44 PM
is there a site for laypeople with info on all the different forms of matter discovered (the stuff on your list as well as anything else) and their properties?
I don't know of such a site [which means you have an opportunity here]. I was just listing the ones that came to mind, and have been discussed recently in the papers and articles I've read.

That being said, aside from BEC, most of them are, as you point out, simply getting hot enough to break a force. Your sense of it is pretty good.

[Duane]

Anton, is there a site for laypeople with info on all the different forms of matter discovered (the stuff on your list as well as anything else) and their properties?

Try here: States of Matter (http://www.visionlearning.com/library/module_viewer.php?mid=120).

[Nereid]

You probably know that as a liquid gets hotter, it gets less dense, and as a gas is compressed it gets more dense. So what happens if you compress a gas so much that its density is the same as that of the (hot) liquid form of the same material?

(If you've already seen a demonstration of this, do let us know what your impression was, the first time you saw it :D )

[StarLab]

As I understand it, for example, at 32 degrees Fahrenheit water ever so slowly transitions between states of matter. So at 212, essentially you'll get a portion of the material as vapor, and a portion as boiling liquid. I'm not sure of any phase between liquid and gaseous.

[Matthew]

The fourth "standard" matter state is the Plasma state where electrons are ripped off the atom.

[Moseley]

Nice link Duane - I have always wondered what Bose-Einstein Condensates were.
I did also see recently some work on some electro-polymers which are liquid (goo) until a high voltage is connected across them when they solidify. This is apparently a fifth state although it seems to be a similar form to solid/liquid as we normally think of them.

[StarLab]

So instead of a higher temperature, after the plasma state all that's needed to form a new state of matter is a voltage increase?

I had imagined that the fifth state would be the breakup of nucleons, and the sixth would be the breakup into quarks.

[Ola D.]

Solids were witnessed to be acting like superfluids under certain conditions by researchers from Pennsylvania University. That was suggested formerly as a theory, but now it has been tested experimentaly.

Here's the article (http://www.sciam.com/article.cfm?chanID=sa004&articleID=000D26B6-0A03-11BF-AD0683414B7F0000)

[alainprice]

0- Bose-Einstein condensate (kinda special, and rare)
1- Solid
2- Liquid
3- Gas
4- Plasma

That's the basic 5 arranged in order of temperature.

I don't see how applying a voltage to go from liquid to solid qualifies as anything new.
I did however recently see an article on a substance that goes from a liquid to solid as temperature increases. That's gotta be worth an honorable mention.

[rahuldandekar]

OK, another question. According to Stefan's Law,

dQ/dt = rho * T^4,

where dQ/dt is rate of loss of heat ( or emission of heat) ,
T is absolute temperate,
rho is Stefan's constant.
rho = 5.67 x 10^-8 SI units.

That is because we take the temperature in Kelvin. Shouldn't we adopt a unit for temerature such that rho = 1.
Wouldn't that be the true natural unit for temperature?