Talk:Evaporation

message: This article is wrong when it says evaporation is when liquid becomes gasous without being heated to boiling point. I'll fix it--124.186.101.229 08:42, 14 November 2007 (UTC)
thread_title: Wrong

message: Has anyone ever fixed "evaporation is when liquid becomes gaseous without being heated to boiling point"? Apparently not. I'll fix it. Dan Hickman (talk) 23:55, 11 December 2007 (UTC)
thread_title:  Evaporation 

message: "On average, the molecules do not have enough energy to escape from the liquid, or else the liquid would turn into vapor quickly." -- this is stupid Needs to be rephrased, as in various cases the liquid does turn into vapor more or less "quickly". -- Writtenonsand (talk) 16:03, 24 July 2008 (UTC)
replies: text: Done (to my few, two eyes).  That segment looked in need of edit to me too, I interpreted it as though they were trying to paint a picture of "what evaporation is in the real world, in contrast to boiling" but they didn't describe "the molecules" enough, and painting a picture doesn't work with too much abstraction.  Now it goes "the molecules in a glass of water," which I think paints the picture they were going for a lot better.  I also tossed in the word & link to "boil," which was left out and I believe the intended contrast the original author meant to make, that is, I don't think it was mere coincidence that the logical phrase "unless it is boiling" is the 100% perfect catch to the statement... although if the glass of water is very near boiling point, some may precive it's rate of evaporation as "quick" but hopefully it is an easy thing to read past.  I'm glad it didn't just delete it, it's a pretty important distinction to make.  —Preceding unsigned comment added by 96.18.60.113 (talk) 08:04, 5 December 2008 (UTC)
thread_title: Needs rephrase

message: Re: "Three key parts to evaporation are heat, humidity and air movement." 
1)  Humidity is a key part of the (important) evaporation of water but not of evaporation in general?
2) Surface area is a key part to evaporation?
Bill B  —Preceding unsigned comment added by 216.69.46.3 (talk) 20:33, 8 September 2008 (UTC)
replies: text: Basically agree with Bill B. When there is a gas-liquid interface with two different components (e. g. air and water), the gaseous part will accept the evaporated liquid only until relative humidity reaches 100 %; then condensation will compensate evaporation; in case of external heat source, the change in temperature may modify the gas-to-liquid ratio in the saturated mix, but nothing more. On the other hand, if the gas-liquid system has a single component (e. g. boiling water), the above simply does not make sense; you may evaporate as long as you feed enough energy. Re point 2 - no, surface area is NOT a key point; it might be influent - sorry for the brutal simplification - since a larger area makes evaporation easier, but the key points is the energy input to the system; in my understanding, also humidity and air movement are not key factors in the change of physical state; they are to be taken into account only as long as you refer to natural evaporation from water reservoirs (lakes, sea, etc.).--Ub (talk) 17:09, 9 September 2008 (UTC)
replies: text: Looking better into the article. The problem is in chapter 2 : Factors influencing the rate of evaporation. The previous part is quite correctly dealing with evaporation; this one concerns psychrometry. Therefore, the considerations by Bill B and myself are in the wrong place. The idea is to look at the main article (psychrometry) and to arrange this one accordingly. Hope to find the time. --Ub (talk) 18:46, 10 September 2008 (UTC)

text: At 0.1 bar water evaporates considerably faster, to the extent that at 50 °C it actually boils, even in dry air.  Your reasoning about partial pressures is fine for a mixture of ideal gases but not when there are phase changes. Vaughan Pratt (talk) 03:08, 19 November 2013 (UTC)
thread_title:  Needs reworking 

message: Link is gone!
DGerman (talk) 00:20, 31 July 2012 (UTC)
thread_title:  Energy costs of form change 

message: this article needs to explain why, after running a dishwasher, plastic or tupperware dishes are commonly still wet long after smooth glass or china dishes are dry.  —Preceding unsigned comment added by 70.131.106.2 (talk) 00:34, 30 June 2010 (UTC)
thread_title:  evaporation time  

message: Isn't viscosity of the liquid a factor whereby there is less evaporation from more viscous liquids? - perhaps more so than density? Is there an expert who can advise on this? Eeno11 (talk) 15:14, 6 September 2011 (UTC)
replies: text: There are effects from viscosity but as AlanParkerFrance said, not in a simple picture.  As a simple example, a thick layer of a viscous 10% polymer solution in a solvent may lose solvent by evaporation at its surface, faster than the solution is mixed by diffusion etc.  This leads to an increase in solids content at the surface, an increase in viscosity, a decrease in mixing etc until the solution has formed a solid or near-solid 'skin' at the surface while the lower layers are still liquid.  The evaporation of these lower layers is now extremely low.  But I wouldn't have thought this degree of complication would be helpful to include in the article.Gravuritas (talk) 12:39, 26 December 2013 (UTC)
thread_title:  Factors affecting evaporation rate 

message: We need an engineer to work on this.  I can supply some input from having worked with evaporators in the pulp and paper industry, but I don't really have time to do it now.  Also I need someone to check my work.  Thanks.Phmoreno (talk) 20:50, 29 April 2013 (UTC)
thread_title:  Help needed 

message: Is the article's account of evaporative cooling complete?  Certainly the statistical account, that the vapor molecules leaving the liquid are the faster ones, must be part of the explanation.  But for it to be the whole explanation, the average translational energy of the departing molecules would have to equal that of the air into which they escape.  (The vibrational and rotational energy need not be the same since water vapor is triatomic and bent while oxygen and nitrogen are only diatomic, but that only makes the cooling effect even greater.)  This seems highly unlikely, even for air well below 0 °C.
More likely, surely, is that on entry to air the molecules are initially well below average in translational energy and are speeded up to average by collision with the other air molecules, and moreover additional rotational and vibrational energy is absorbed.  This will reduce the temperature of the skin layer of air, and then it's a good question how that cooling effect on the skin layer is divided between the liquid below and the air above.
Is this in fact the case, and if so is there a source for it?  If there is it should go in the article.  If not it sounds like a nice little project for a physics student to investigate, especially the question of how the skin layer cooling is apportioned between liquid and air, presumably as a function of the temperatures of the respective phases.  Vaughan Pratt (talk) 18:43, 28 October 2013 (UTC)
thread_title: Mechanism of evaporative cooling

message: It seems to me that this article could have been edited less arrogantly and destructively.  Is it necessary to say, "This article is wrong", or, "this is stupid"?
Due to the way this Talk page was edited, I'm not sure who asked, "what is the answer then?", or whether the question was ever answered.  However, the fact that the question was asked after two people said they would "fix it", suggests destructive editing.
Hopefully, obsolete explanations will not be included in the, "wrong", and, "stupid" categories; they are history, and should be included in the History section.  Ideally, a History section about a chemistry subject would go back at least as far as Alchemy, and perhaps back to ancient applications of the subject. In the case of Evaporation that would probably include early stills and porous ice trays and jugs such as ancient Egyptians and others used to chill water, and Mesoamerican descendants continue to use. Downstrike (talk) 13:33, 15 November 2013 (UTC)
replies: text: Are you asking about the history of this talk page or the history of evaporation?  Your comments seem to be addressing both.  For the former, use the history tab to locate specific examples of "destructive editing" of this talk page (I took a look and was unable to find any).  For the latter, see Evaporative cooler and distillation, both of which have long history sections.  Evaporation itself presumably began not too long after the Big Bang, what would you like to see about its history in this article?    Vaughan Pratt (talk) 17:02, 15 November 2013 (UTC)
thread_title:  Where's the History? 

message: in "Factors influencing the rate of evaporation" the "Concentration of other substances in the air" should not have effect, the correct factor should be "Concentration of other substances in the liquid".
139.78.154.131 (talk) 18:34, 24 February 2016 (UTC)
replies: text: Not done: as you have not cited reliable sources to back up your request, without which no information should be added to, or changed in, any article. - Arjayay (talk) 19:14, 24 February 2016 (UTC)
thread_title:  Semi-protected edit request on 24 February 2016 

message: The final sentence of the lead seems to me to be a bit odd. "The tracking of evaporation from its source on the surface of the earth, through the atmosphere as vapor or clouds, and to its fate as precipitation closes the atmospheric water cycle, and embodies the concept of the precipitationshed." 
First off, it's a bit of an awkward sentence to make sense of.
Second, and more important - why is precipicationshed there? It's a bit of a niche concept, and consensus on Talk:Precipitationshed seems to be that it's not really a word. Why is it even mentioned in the lead paragraph of the article on evaporation? 
I think this sentence could be tidied up grammatically, and should drop the mention of the precipitationshed (while perhaps retaining reference to the water cycle). Girth Summit (talk) 07:08, 31 October 2016 (UTC)
thread_title:  Precipitationshed in the lead? 

message: 223.235.143.135 (talk) 08:59, 12 June 2020 (UTC)
replies: text: Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format and provide a reliable source if appropriate. TheImaCow (talk) 10:48, 12 June 2020 (UTC)
thread_title:  Semi-protected edit request on 12 June 2020 

message: Oxidation state 102.143.9.200 (talk) 04:01, 5 April 2022 (UTC)
thread_title:  Chemistry 

message: Fggg 171.76.86.157 (talk) 15:00, 31 July 2022 (UTC)
thread_title:  Evaporation