Talk:Phase (matter)

message: There are several misconceptions of phases, and specifically phase transitions in this article. Mostly, it completely ignores second-order phase transitions, in which the free energy function stays differentiable, even at the transition. This also means, that the latent heat (energy related to the change in phase) is zero at the critical value. A perfect example of this is mentioned just above here: the superconducting phase transition. At some critical temperature (or critical magnetic field strength, but this is a bit touchy, as some energy is related to displacing the magnetic field around the superconductor), metallic superconductors become superconducting, which, as mentioned, is a different phase of matter. However, no energy is released in the process, nor is any taken up. This is in clear contradiction to a number of statements in the "General definition..." section. The page on phase transitions has a much clearer description, which should be linked to in stead.
195.215.65.50 (talk) 21:59, 28 November 2007 (UTC)
thread_title:  Second order phase transitions 

message: According to   there should be more than 500+ phases -- 70.24.247.127 (talk) 01:27, 25 December 2012 (UTC)
thread_title:  500+ phases 

message: I would like to have all known phases of matter listed somewhere, either in the form of a bullet list or as a table. Currently, you just have to read the text in hope of finding them all implicitly listed somewhere, although they are not. Could anyone who know which all these phases are please make a list of them? —Kri (talk) 21:03, 21 July 2014 (UTC)
thread_title:  List of phases? 

message: Can we have a section on the history of the discovery of phase structures, please?  — Preceding unsigned comment added by 176.252.227.106 (talk) 13:08, 25 January 2015 (UTC)
thread_title:  History 

message: In the last paragraph under number of phases is the following: "By charging the right amount of water and applying heat, the system can be brought to any point in the gas region of the phase diagram. " 
1) The syntax of charging the right amount of water seems a bit clunky and probably refers to a specific experimental apparatus? I interpret it to mean controlling the amount (mols I assume - but that is problematic because we don't have a vloume) of water in the described system.
2) Going from the amounts issue above: the relative amounts of material in a system is a variable that can affect phase but is not what is represented in the attendant 2D phase diagrams (only T & P are). It is probably best to avoid adding compositional axes too for this discussion.
Suggestion: Could we edit this to say something like "By controlling the temperature (degrees K) and the magnitude of pressure (here shown in MPa) the system can be brought to any point on the phase diagram. From a point in the solid stability region (left side of diagram) increasing the temperature of the system would bring it into the region where a liquid or a gas is the equilibrium phase (depending on the pressure).
By CrispGeochem  — Preceding unsigned comment added by 151.213.119.209 (talk) 16:27, 1 May 2020 (UTC)
replies: text: Good suggestion. I have copied most of your two sentences into the text, although I left out the units since other units could be chosen also. Dirac66 (talk) 15:32, 9 May 2020 (UTC)
thread_title:  Right amount of water