Talk:Physical change

done

Recommend Edit Protection
Apparently, some people have decided it be fun to edit this page. I recommend that either semi edit protection or full vandalism protection be enacted to prevent future vandalism. 75.181.53.227 (talk) 23:05, 16 December 2008 (UTC)
 * Rule of thumb: The more likely a page will be read by junior high students, the more likely it is to be modified inappropriately. I favour semi-edit protection. So, how do we set it up? Ronstew (talk) 04:08, 17 December 2008 (UTC)
 * ? 50.238.66.122 (talk) 12:19, 9 September 2022 (UTC)
 * no 50.238.66.122 (talk) 12:19, 9 September 2022 (UTC)

Yamate ugh — Preceding unsigned comment added by 136.158.82.47 (talk) 01:26, 4 October 2021 (UTC)

Ions in solution?
When NaCl dissolves in water, it dissociates into Na+ and Cl- ions. Do we consider this a chemical reaction? Simple evaporation of the water restores the salt crystals. Ronstew 03:50, 22 February 2007 (UTC)

. —Preceding unsigned comment added by 121.54.2.85 (talk) 07:04, 2 October 2010 (UTC)

Dispute over some examples
User 72.140.220.86 put this in the body of the article:
 * THESE ARE NOT PHYSICAL CHANGES! Crumpling a paper doesn't change the paper. Similarly, smashing a piece of ice is not a physical change. MELTING THAT ICE IS A PHYSICAL CHANGE. Physical changes involve a change in the intermolecular forces between molecules. Chemical changes are changes between the intramolecular forces resulting in a new bonding conformation.


 * Maybe one of us needs to add some references, no?

It would be nice if the user had offered a reference of his own, but we should consider the comments. I note that in the user's terms, smashing ice IS a physical change. Intermolecular bonds are broken, which seems to me to be a new conformation.

User 72.140.220.86, can you give an example of a physical change that is not a state change? I wonder (and am not being sarcastic) if the creation of an artificial diamond from graphite might qualify under your definition. Ronstew (talk) 06:12, 9 February 2009 (UTC)


 * Smashing a piece of ice and melting them would both be physical changes, it isn't changing what it's made up of. Glacialfox (talk) 23:12, 15 December 2011 (UTC)

No i'm sorry, but smashing ice would not be a physical change whereas, melting ice would be, when you smash ice it doesn't actually change in anyway, apart from becoming smaller, melting ice would be completing changing the state of the ice, therefor it's a physical change and smashing ice isn't. — Preceding unsigned comment added by 94.175.58.221 (talk) 18:58, 4 June 2013 (UTC)

Problems with this page
It is not al all clear what this page is about. There is no referenced definition and the scope of the article could potentially be enormous including much of metallurgy, crystallography, materials science etc etc. It reads very much as if it originated from an introduction to science lesson at school in which the teacher tries to highlight the differences between chemical reactions and other things such as simple mixtures. I suspect if this was well thought through it might almost become a copy of Physics. At present I do wonder what purpose it serves. If it can't be improved it might be better served at AfD.  Velella  Velella Talk 07:29, 21 November 2011 (UTC)


 * Yes, the fuck and baddely used in school textbooks, but is problematic and a poor example. I always had trouble with that when teaching intro chem classes, because we would later in the course cover chem reactions involving dissolved salts as ions in solution.
 * The page along with physical property, chemical property, chemical change (all of which need work) could perhaps be in a category:Introductory chemistry. Vsmith (talk) 14:05, 21 November 2011 (UTC)
 * Added definition from Zumdahl college chem text. Vsmith (talk) 15:01, 21 November 2011 (UTC)


 * I have added further and also substantially re-written Chemical change. Still no references which I will try and seek out given time. I would welcome views whether these changes have actually made any improvement or whether presenting science at this level in an encyclopaedia (rather than the class-room) is doomed to inevitable failure.  Velella  Velella Talk  23:44, 23 November 2011 (UTC)


 * Yup, this page is incomplete. I'll try to help. A random person 22:37, 8 December 2011 (UTC) — Preceding unsigned comment added by YOPbottle (talk • contribs)

Semi-protected edit request on 22 March 2015
the way a chemical reacts is also the way a dog barks.

166.62.152.231 (talk) 23:28, 22 March 2015 (UTC)


 * as you have not requested a change. Please mention the specific changes in a "change X to Y" format. --I am  k6ka  Talk to me!   See what I have done  23:37, 22 March 2015 (UTC)

Alloys
Could one please add, that some alloys e.g. high tin bronze form intermetallic phases which are regarded by many chemists as new compounds, but not as mixtures? They behave in the same way as silver oxide, which is a chemical compound, but not a mixture of oxygen and silver, although one can simple heat silver oxide to seperate it into oxygen and silver. The structures of those intermetallics are very different from the lattices of the pure elements and inded they are in many aspects more like ceramics than metals. This shows us, that the difference between chemical and physical changes can be blurred in "real" settings although the concept is very useful for idealised and simplyfied model settings. — Preceding unsigned comment added by Xyrofl (talk • contribs) 13:35, 30 April 2015 (UTC)