SNAVEZNAD Posted October 17, 2005 Share Posted October 17, 2005 Is there anything that is evn older than liquid Helium:confused: or isit the coolest of the cool? Link to comment Share on other sites More sharing options...
YT2095 Posted October 17, 2005 Share Posted October 17, 2005 it`s the coolest. at 4.215 kelvin Link to comment Share on other sites More sharing options...
RyanJ Posted October 17, 2005 Share Posted October 17, 2005 As far as I know Solid state Helium is the coldust any substance needs to be coolled too in order to freeze. Some interesting properties of liquid helium are that it seems to defy gravity and climbs up the side of container... very odd stuff... Its melting point is -272.2 and so at anyhting below that temperature it is solid, just a few degrees above absolute zero (−273.15) which is the temperature that we can never reach.... Cheers, Ryan Jones Link to comment Share on other sites More sharing options...
Klaynos Posted October 17, 2005 Share Posted October 17, 2005 a mix of two isotopes of helium can be made that has a temperature below 1K It is possible to make things colder with laser cooling I belive... Link to comment Share on other sites More sharing options...
swansont Posted October 17, 2005 Share Posted October 17, 2005 4 Kelvin? Bah! I thought you wanted cold! Simple laser cooling in my lab gets Cesium and Rubidium down to about 2 microKelvin. Bose-Einstein Condensates get down to nanoKelvintemperatures. Link to comment Share on other sites More sharing options...
CanadaAotS Posted October 17, 2005 Share Posted October 17, 2005 Bose-Einstein Condensates? Thats when all the molecules sorta stick together and act like a big molecule (when its really cold), right? I wish I had some solid helium lol *Throws a helium ball at the forum* heh Link to comment Share on other sites More sharing options...
YT2095 Posted October 17, 2005 Share Posted October 17, 2005 LOL, Hey, I`m just a humble Chemist dude, that`s what`s in the data book as the BP Link to comment Share on other sites More sharing options...
jdurg Posted October 17, 2005 Share Posted October 17, 2005 The only way you get solid helium is by putting liquid helium under pressure. Under normal atmospheric pressures, helium is I believe the only element/substance that does NOT have a solid phase. (Helium is only solid at very low temperatures and higher pressures). Link to comment Share on other sites More sharing options...
RyanJ Posted October 17, 2005 Share Posted October 17, 2005 The only way you get solid helium is by putting liquid helium under pressure. Under normal atmospheric pressures, helium is I believe the only element/substance that does NOT have a solid phase. (Helium is only solid at very low temperatures and higher pressures). Really, thats kind of cool Makes helium quite a unique element! Also, when in its liquid form it seems to defy a lot of the laws of physics, it climbs up the side of beakers and stuff - its really wierd! Cheers, Ryan Jones Link to comment Share on other sites More sharing options...
swansont Posted October 17, 2005 Share Posted October 17, 2005 Bose-Einstein Condensates? Thats when all the molecules sorta stick together and act like a big molecule (when its really cold)' date=' right? [/quote'] The (well, one) neat thing is that they don't stick together - it's still a gas. Link to comment Share on other sites More sharing options...
5614 Posted October 17, 2005 Share Posted October 17, 2005 Like swansont said, they don't stick together because it is still in the gaseous state, however they can 'act as one', for example like in this article: http://www.world-science.net/othernews/051014_emptyfrm.htm (As a side point that article is actually a very good read for basic/intermediate in wave/particle duality, uncertainty, bose-einstein condensates and the whole article is generally about virtual particles... but maybe the link would go down better in the physics section.) Link to comment Share on other sites More sharing options...
vrus Posted October 18, 2005 Share Posted October 18, 2005 Also' date=' when in its liquid form it seems to defy a lot of the laws of physics, it climbs up the side of beakers and stuff - its really wierd! [/quote'] One of my book says that there exists a 'super-fluid allotrope' of Helium, the can climb out of its cantainer ! A super-fluid is a fluid that has or creates no friction right ? Link to comment Share on other sites More sharing options...
RyanJ Posted October 18, 2005 Share Posted October 18, 2005 One of my book says that there exists a 'super-fluid allotrope' of Helium' date=' the can climb out of its cantainer !A super-fluid is a fluid that has or creates no friction right ?[/quote'] Yup, correct - its nuts like I said it seems to break the laws of physics in some cases! Cheers, Ryan Jones Link to comment Share on other sites More sharing options...
CanadaAotS Posted October 18, 2005 Share Posted October 18, 2005 so lets just say you wouldnt get immense hypothermia and die quickly if you slathered this stuff all over you. you do it, then you could slide up walls and stuff lol does it defy laws of physics, sort of like how superconductors can make things hover? Link to comment Share on other sites More sharing options...
The Thing Posted October 18, 2005 Share Posted October 18, 2005 Superfluidity is the ability to flow without viscosity. Superfluids do "defy the laws of physics", as it can move along (due to its shortage of any viscosity) without friction. It's kind of like superconductors, as it is a super-thermal-conductor, and like it is impossible to set a voltage difference in a superconductor, it is impossible to set a heat gradient in superfluids. Link to comment Share on other sites More sharing options...
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