[neilep (OP)]

Dearest  Coldologists !


'Absolute Zero' is well cold innit ?   


As a firm believer in empirical study  I snuck into my neighbours house at 3am this morning and put his air con onto max and dangled some ice cubes over his head. I also pipe fed him his favourite brand of vodka despite his playful protestations that he had just become clean after 15 years of going to AA. Oh well.


Anyway, the best I could do is drop his temperature a single degree. I blame his body's lack of cooperation. So, no luck there then !


What I was attempting to achieve is to see what would happen at Absolute Zero but found this very difficult to achieve.......then.....after stuffing my neighbour in the freezer I realised after 5 hours that it's impossible to achieve absolute zero and gave up and came home.


however, I thought "How Is The Temperature of Absolute Zero Known If We can Never Achieve It ?"




I dunno, shrugging my shoulders and stuff  !


Please to be accommodating my request with an answer.


Thank Ewe




hugs et les shmishes
mwah mwah mwah !!


neil
xxxxxx


ps: I later found out that my neigbours freezer was defrosting.
pps: The Naked Scientist Website does not condone stuffing your neighbour into the freezer. Sheepy is a trained sheep and knows what he is doing.

[Halc]

How Is The Temperature of Absolute Zero Known If We can Never Achieve It ?

How was it known to today's precision?  I don't know the history of that. The law of gasses gives a good guess.
It says that "the pressure of a given amount of gas held at constant volume is directly proportional to the Kelvin temperature" so you grab a bottle, fill it with some gas, seal it, put the bottle in a vacuum, and then measure the temp and pressure. Then do that at other temps. Graph what you get. It should give a pair of straight lines for pressure and temp. Extrapolate the lines down to where the pressure is zero and where the temp line is yields absolute zero, Kelvin.

I say I don't know how because that only gets you an approximation.  You cool a gas enough and it suddenly becomes liquid and that has to mess with the pressure curve since it is now (mostly) sitting at the bottom of your bottle and is not so busy pressuring it.

[Bored chemist]

The temperature of absolute zero is exactly zero- by definition.

What you measure is the temperature, (relative to the temperature  of the triple point of water) of the freezing and boiling points of water to establish what 0^oC and 100^oC are

[Petrochemicals]

If temperature is a measure of movement over time it creates a problem. If you take an instant, a photographic moment that is impossible to have, all matter would essentially be not moving and therefore absolute zero, coversley any measure over time is open to infinity.

[paul cotter]

??

[alancalverd]

The question is unanswerable because it is backwards!

We define absolute zero as the temperature of a heat sink at which a Carnot engine would reach 100% efficiency.

What makes it intriguing is that this condition would be independent of the temperature of the heat source.

What makes it unreachable is the inverse rider that it would require the expenditure of an infinite amount of energy to remove the last infinitesimal amount of heat from an object.

[Bored chemist]

If temperature is a measure of movement over time it creates a problem.

But it isn't, so there's no problem. Obviously.

This is the sort of thing that PC's signature refers to as "repetitive antagonism".