Talk:Superheating

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Superheated fluid in nature[edit]

"Because a superheated fluid is the result of artificial circumstances" - I remember watching a program on undersea life, and it said that underwater volcanoes can heat water to extremely high temperatures, but because of the immense pressure it does not turn into a gas. I cannot remember the name of the program, and thus there is no source. But I'm sure that superheating occurs in nature.

Still, this woulnd't count as superheating, since it is true that at those pressures, water isn't at its boiling point. As the pressure increases, so does the boiling point- and thus those underwater vents don't actually superheat. Superheating requires that the temerature exceeds the boiling point, something that I'm doubtful can happen in nature.

it was on the whale program on bbc1 just now Wolfmankurd 19:26, 31 May 2006 (UTC)

Microwave Section Rewrite[edit]

This paragraph needs a rewrite.

"However, that is not to say that an old container automatically is safe. It may happen that you have heated water in an old glass hundreds of times with no problem, then one day while you are doing that the phone rings and you shut down the microwave just to be safe. Ten minutes later, when you heat the water again, you touch the glass and it explodes. The problem is that the scratches holding bubbles, first of air and then of water vapor, were preventing the water from exploding, but when you heat it and let it cool all the bubbles are reabsorbed, so when reheating there are no nucleation points." Bold added for emphasis JohnJohn 04:47, 2 November 2006 (UTC)

I think the term 'common' is probably misleading, since even the linked documeunt (snopes) says true but rare. I don't think this is even a truely relevent section for that matter.

I have experienced "exploding" water from a microwave years ago but I could not comprehend what happened. My son had some superheated chowder explode and burn his face a few days ago. My comments are 1)the microwave section is relevant, 2) currently the references to the microwave are about water, not about a fluid like chowder. I did not just go and change the word water to fluid because it may not be fully supported by the reference. Thanks for the great info. Jim Derby (talk) 15:19, 2 January 2014 (UTC)

Clarify[edit]

To prevent this, adding something to the water prior to heating it is suggested.

This cannot be let this way in the article, and has to be subst. clarified. Otherwise it should rather be replaced with a more forceful warning. --Slicky 11:25, 16 February 2006 (UTC)

What is your source for slow nucleation => superheating?

CaveShvig


I think there are major problems with your "microwaving" discussion. The liquid / solvent system boiling point changes with the addition of an electrolyte. The system is not superheated because it is not above the boiling point!

CaveShvig


elaborate please —Preceding unsigned comment added by 203.39.51.116 (talk) 04:40, 5 August 2010 (UTC)

"Defervescence"?[edit]

This term was cute, but struck me as odd. The meaning of this term is the subsidence of a fever, and has nothing to do with superheating (although the root words are related). A quick google search showed that all but one indexed incidences of this word in the context of superheating go back to the text in the Wikipedia article. Adding a search term that removed pages with text from the article was used to narrow it down, and the only pages remaining were a few spam sites, sites using the correct fever-relating meaning of the word, some translations of the wiki text that left the word unchanged, and the previously mentioned single page.

On the page where it was used outside of the context of the article, the author appeared to be new to the word, and I have a hunch he got it from the article in question.

I realize that Google is not good research material, however I think it can be used here as compelling given the lack of research provided in support of the assertion, unless someone comes up with a real citation.

Relevant search terms in Google.

The only page I could find that actually uses the term this way.

134.50.7.201 10:18, 17 December 2006 (UTC)

After more searching of French-language pages (the redirect asserts that "defervescence" means superheating in French), I still can't find any pages using the term in any context other than relating to the fever-related medical condition. I believe the redirect's assertion is bogus as well.

134.50.7.201 10:30, 17 December 2006 (UTC)


Superheated steam?[edit]

Is superheating with regards to superheated steam a different sort of superheating? There, it refers to heating water again after it has become steam, so that the steam can reach temperatures above 100 degrees Celsius at sea level (300 degrees is possible). The article seems to be referring to something else. --204.4.131.140 11:15, 29 October 2007 (UTC)

Uhm... water in liquid form and an normal pressure can reach 100C before is turns into stream... but after that, the gaseous water can - of course - be heated as much as you like (until it becomes plasma).... just as ice can be cooled significanlt below 0C.
So... what is the question here? I'm not sure I understand you. --J-Star 12:28, 29 October 2007 (UTC)

No superheated steam is different and should have its own page. xbgs351 11 March 2008 —Preceding unsigned comment added by 123.243.254.204 (talk) 00:31, 11 March 2008 (UTC)

Impure water and superheating[edit]

I've made some amendments to the following part of the article so that it's now clearer.

"However this is very, very rare and can only happen under certain conditions, like the water having no impurities. Any foreign object in the water, whether it be a spoon or a salt cube, greatly diminishes the chance of an explosion because it provides nucleation sites."

This information is wrong according to this. [1] Anyone care to try microwaving cooled coffee and adding sugar to it?

Mysterial (talk) 11:38, 23 November 2007 (UTC)

Placed it under another section as Myth to avoid confusion and did a slight bit of rewriting and cited sources. Mysterial (talk) 08:07, 24 November 2007 (UTC)

Impure substances without seed-bubbles cannot superheat?[edit]

This is untrue because nucleation points for boiling do not include solid nucleation centres, but rather, seed-bubbles that occur due to the presence of solid nucleation centres. In other words, if there are solid nucleation centres in a substance (e.g. impure water) but without seed-bubbles (e.g. leaving impure water to stand or boiling it once to rid the water of the bubbles), superheating cannot occur.

This seems internally contradictory and inconsistent with the cited sources. The last sentence perhaps should read instead, "...if there are solid nucleation centres in a substance but without seed-bubbles, superheating will occur."


Mechanics Section Rewrite?[edit]

The mechanics section reintroduces the "microwaving coffee" example several times. The section should be rewritten to condense the paragraphs about this phenomena into one. —Preceding unsigned comment added by W09110900 (talkcontribs) 17:25, 1 July 2008 (UTC)

The Myth of the Boiling Point by Hasok Chang[edit]

Might be of interest here, especially the part on the superheating race.

Chang, Hasok (18 October 2007). "The Myth of the Boiling Point". Gower Street, London WC1E 6BT, Great Britain: University College London, Department of Science and Technology Studies, Faculty of Mathematical and Physical Sciences. Retrieved 13 May 2009.CS1 maint: location (link)

Superheat: The Best Way to Tune an Air Conditioning System[edit]

http://contractingbusiness.com/residential/cb_imp_17963/ I think this should be added to this topic as it is The Method to determine air conditioning (and heat pump) performance. I will put it in my own words in the future. Please read link and make suggestions or feedback to me thanks!Avaghnn (talk) 02:04, 2 December 2011 (UTC)

I read the link. I can't tell if the term "superheat" in that link is really referring to the same thing as this WP article. That's not to say it isn't relevant, but I just want you to be aware that they could be talking about something completely different. And therein lies a big problem with the link: the wording isn't very clear. They just say "hotter than the boiling point"; they don't say it's because of lack of nucleation sites or what. They further the confusion (in my mind anyway) by using "superheat" as a noun. Spiel496 (talk) 18:38, 5 December 2011 (UTC)