Talk:Vacuum flask

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A good Thermos resource link[edit] seems to cover a wide range of Thermos items and articles and would be a good link resource for readers. 15:12, 27 March 2006 (UTC)

Perfect insulation?[edit]

I removed the following paragraph

In theory, a vacuum flask could therefore approach arbitrarily close to perfectly insulating fh, for example keeping a cup of coffee hot for a decade. In practice, however, the inside wall of the container must meet the outside wall, usually at the mouth of the container, at which point slight heat conduction does occur between the inside and outside walls (the vacuum being in between).

since I think it is misleading. While conduction is the primary route of heat loss for most materials, radiation is also important. I can't imagine decade-scale insulation, since heat would necessarily be lost through radiation. Thoughts? --TeaDrinker 19:53, 13 November 2006 (UTC)

Sounds like you were correct to remove it. (talk) 21:19, 22 November 2007 (UTC)
Yes, it's always important to get "consensus" from anonymous sources. That's how science is done in the contemporary political climate. Phhhht! —QuicksilverT @ 16:11, 2 April 2009 (UTC

Radiation is a factor but is minuscule because of the shiny coatings. Decades, no, but it does transfer more heat from the conduction at the neck than anyway else.

Vacuum flask was invented by Adolf Ferdinand Weinhold[edit]

Already in 1881 Adolf Ferdinand Weinhold published a book in which he described a vacuum flask, similar to the "Dewar flask", for use in the laboratory. Only 10 years later did Dewar invent the flask for a second time. Should be mentioned. -- (talk) 14:27, 26 January 2008 (UTC)

Surface Area[edit]

Should the low surface-area:volume ratio of the inner flask be mentioned? (i.e. that it minimizes heat transfer) —Preceding unsigned comment added by LaFoiblesse (talkcontribs) 20:49, 14 February 2008 (UTC)

No, surface-area:volume ratio is not relevant. The flask of any shape inside that has double walls with nearly vacuum in between will be therefore still a Dewar flask. There are different ways to reduce heat dissipation; one of them (double walls with vacuum in between) is the topic of this article. Other strategies (reducing of the surface-area:volume ratio, additional heating/cooling of the outer walls, etc.) can be used, but they are not the topic of this article. Adams13 (talk) 12:32, 23 January 2013 (UTC)

Could anyone please supply a photo for the domestic variant? :)[edit]

I can only see the industrial variant for liquid oxygen or nitrogen, which -- no doubt -- would not have much importance in everyday life. :) -andy

You mean like making liquid nitrogen ice cream?
I saw them "cook" with liquid nitrogen on Iron Chef. Perhaps a picture of that, if we can obtain the rights?
The most popular everyday domestic use of liquid nitrogen, I believe, is freezing random objects and smashing them.
Let me know what sort of photo of domestic use you want, and I'll take one when I get my dewar in a couple weeks. Minetruly (talk) 01:28, 10 August 2010 (UTC) (talk) 22:24, 28 October 2008 (UTC)


Not sure why this article is labelled start-class. I looked it up and found all the information I wanted (and more). --Martin Wyatt 20:16, 19 March 2011 (UTC) — Preceding unsigned comment added by MWLittleGuy (talkcontribs)

History is wrong in article[edit]

and German Reinhold Burger built then Vacuum flasks after the ideas of chemist Adolf Ferdinand Weinhold (talk) 22:11, 7 May 2013 (UTC)

I looked at the German wikipedia article on Weinhold for a reference, instead they give an earlier date for Dewar, with reference: Dewar had used a vacuum vessel as an insulator in calorimetrical experiments in 1874, at the University of Edinburgh. This date came out after a claim of Louis Paul Cailletet who thought he antedated Dewar in this invention. [1]. I don't know the significance of the 1892 date in this context, so I leave it to someone else to correct the article...Ssscienccce (talk) 22:14, 6 September 2013 (UTC)

Wrong Units in Eq. 3[edit]

It seems that the mass term has been dropped from Eq. 2 to 3. The units don't work out for Eq. 3. I think Eq. 2 should have had 1/m since both entrophy and enthalpy contain 1/m. Sameb112 (talk) 18:37, 4 October 2013 (UTC)

  1. ^ Sloane, Thomas O'Connor (1900). Liquid Air and Liquefaction of Gases. New York: Norman W. Henley & Co. pp. Chapter XI, especially page 232.