Pop quiz: States of matter

[unixronin]

OK, folks, let's test your scientific knowledge.

[Poll #1278483]

Most grade school science classes still teach that there are three states of matter — solid, liquid, and gas.  But there are several others.

• If you heat and compress any substance beyond its thermodynamic critical point, the result is a supercritical fluid that behaves in many respects like a liquid and like a gas simultaneously.  If you drink decaf coffee, it's likely it was decaffeinated using supercritical carbon dioxide.
• If you pump sufficient energy into any substance possessing atomic structure, its electrons become dissociated from the atomic nuclei, forming a plasma, a highly energetic cloud of free electrons and nuclei.  Plasmas behave like gases in most respects, but have several useful additional properties.  Fluorescent lights (including CFLs) and neon tubes employ plasmas, as do the various experimental fusion reactors that rely on magnetic confinement.
• Compress any normal atomic matter enough, and its atomic structure collapses.  This gets us into a whole class of states of matter known collectively as degenerate matter.  The most common form of degenerate matter is probably the electron-degerate matter believed to compose white dwarf stars, while the best known is what used to be called neutronium, now more correctly termed neutron-degenerate matter.  Weirder, possibly speculative members of the family include strange matter, quark matter (aka QCD matter), and possibly preon matter.
• As several people have reminded me, if you cool a substance sufficiently, slowing its atomic motion until the atoms are essentially at rest, their position becomes uncertain due to Heisenberg's uncertainty principle, and the wave functions of the atoms spread out accordingly. If you can cool therm enough that their wave functions overlap, you get a Bose-Einstein condensate — a cloud of atoms all in exactly the same quantum state, acting as though they were one giant atom.  (However, the atoms you start with have to be bosons.)

So if you answered "Six or more", you're correct.  Probably.  As far as we know.  For now.  And remember, this isn't an exhaustive list.

Comments

[otherbill.livejournal.com]

I said six. I could only come up with five, but figure there's at least one we haven't discovered yet.

(On a completely unrelated note, would you mind weighing in here (http://otherbill.livejournal.com/360284.html)?)

[unixronin.livejournal.com]

I saw that, but couldn't really come up with a better suggestion than VNC, which you'd already mentioned. It works well, it's fast, and it's free.

[otherbill.livejournal.com]

How much should I worry about security here? gundo said to wrap it in ssh, but I don't know how to do that.

If it's sitting behind a reasonably-secured wireless router, will the free version be sufficient, or should I shell out the $30 for the Personal Edition (w/ security/encryption)?

[unixronin.livejournal.com]

Well, that's not necessarily a simple thing to do. Basically it means you have to create an ssh tunnel either to the box in question, or to some other machine in between that can gateway for you. This means the remote end of your tunnel needs to have an sshd, which for most purposes means it has to be some flavor of *nix box.

The basic concept is like this: You tell ssh on your box that it is to establish a persistent SSH connection to a specified port on the remote machine, listen for connections to port X, and forward them over that SSH connection. Meanwhile, the remote machine has been told that packets coming in over that SSH connection are to be forwarded to the VNC port on the target machine. (And vice versa in the other direction.) You open a VNC connection to the designated port on your own machine, and through the magic of ssh tunnelling, the other end of the connection gets attached to the target machine.


As for the second question, that's really unanswerable without knowing how secure you need it to be. My first reaction, though, is that wireless connections are slow to start with. VNC over an encrypted wireless connection is likely to be agonizing. It'll be usable in an emergency, but I wouldn't want to do work over it on a regular basis.