Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Gas, Liquids, and solids : Details

  1. Sep 15, 2010 #1
    From what I know, a liquid is H2O and its atoms are moving constantly. But when it freezes it atoms start to slow down and the liquid is a solid. So the question is there any other way to turn a liquid into a solid?
  2. jcsd
  3. Sep 15, 2010 #2


    User Avatar

    Staff: Mentor


    If the picture doesn't display - please let me know.

    Try to read what happens when you increase pressure for a given temperature.
  4. Sep 15, 2010 #3

    Just to add a bit of information to Borek's phase diagram in case you have any difficulties, the blue part represents all the solid phases of water. Pick any point in the green area, the liquid phase. If you follow a straight vertical line, you are keeping the temperature constant. By going up into this line, you are increasing the pressure without changing the temperature and you can reach the solid phase doing that.

  5. Sep 16, 2010 #4
    So can a gas turn to a solid?

    And also thanks for the info.
  6. Sep 16, 2010 #5


    User Avatar

    Staff: Mentor

  7. Sep 23, 2010 #6
    Another question is that can electricity be positive. Like can it be protons instead of electrons?
  8. Sep 23, 2010 #7


    User Avatar

    Staff: Mentor

    I would love to know what you are asking about.
  9. Sep 23, 2010 #8
    Yes. In a metal, the e- are the obvious charge carriers.

    However, in a crystal, whether it is metallic, semi-conductor, ionic etc, there are always vacancies. Those are locations where there should be an atom, but it is missing. This allows all the other atoms, which may be effectively positive or negative, to move in the vacancy ("hole") successively. Effectively, it looks like if it was the hole that was moving. In semi-conductors especially, a hole can also be a missing electron.

    Another example is cell membranes, including our own nerve cells. The carriers here are ions of various atoms. Some are positive and some are negative. Here is a nice diagram:


    Becoming those carriers is somewhat the destiny of the salt in the food we eat. Actual proton currents can also be found in some specialized areas of living organisms.

    The current within a battery is also ionic, the carriers can either - and + ions as far as I know
    Last edited: Sep 23, 2010
  10. Sep 23, 2010 #9


    User Avatar
    Staff Emeritus
    Science Advisor

    Valence electrons in a conductor (IE a wire) are able to move through the material by jumping from atom to atom i beleive. That is electricity in a nutshell, the movement of those charged particles. I can't see an easy way to create useful electricity using Protons.

    Edit: Dr Lots-o'watts post above has good examples of using positive ions to accomplish something. Strictly in the sense of powering electronic devices and transporting electrical power, only electrons are used. The positive ions in a battery are merely a place for the electrons, from negative ions, to deposite themseleves. The electrons run from the negative side of the battery, throughout the circuit, and end up attaching to the positive ions on the positive side of the battery. I guess it all depends on what you mean by your question Kienken, as it is pretty general.
    Last edited: Sep 23, 2010
  11. Sep 24, 2010 #10


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Please do not ask multiple unrelated questions in the same thread. Instead, you should start a new thread with an appropriate title (but first search the forum to make sure your question hasn't already been asked and answered).

    Post #8 by Dr L'oW provides a very good answer to your question. If you need to follow up or discuss it further, please ask to have this separate discussion split off into a different thread.
  12. Sep 24, 2010 #11
    Thanks and I will start this on a new thread.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook