Great Western Coffee Shop

Celcius, rather than Centigrade.  ;) ;D




Edit note: As this discussion was going 'off topic' from the original 'turbo refurbishment' thread, at http://www.firstgreatwestern.info/coffeeshop/index.php?topic=6176.msg71734#msg71734, I've split the following erudite posts into this new topic. CfN. :)

That would be Celsius. My cousin lives a couple of doors down from his former home in Uppsala http://www.uu.se/en/node899. And while centigrade does have a very respectable track record for meaning exactly the same thing, I wouldn't want to get into trouble with the scientists again.

Touch^.  ::)

I can vouch for that. It's been pretty unpleasant on the mid-Atlantic east coast for a month or more now. The daytime maximum temperature hasn't been below 90F (about 33C) for weeks, and has more often been around 95-100F (35-38C) which combined with significant humidity makes going outside a bit of an ordeal.

I'm a bit puzzled by the press story about the DC metro though, I've used it several times including in the height of summer and never encountered a train without working a/c, so the suggestion that three trains in a row had none seem, erm, a little surprising to me. And it's also factually incorrect becuase the stations aren't air conditioned!


No need to worry about that, real scientists use Kelvin anyway ;) The gradations are the same as the Celcius scale but the zero point is set to absolute zero, the point at which all atomic vibration in a crystal would cease. It's a theoretical temperature because no-one's ever managed to get anything that cold, although it's possible to get very, very close. Net result of which is that water freezes at 273K rather than 0C, and boils at 373K instead of 100C.

Science lesson over.

273.15K and 373.15K actually! ;)

Which, as I'm sure you'll remember from you school maths lessons, rounds to 273K and 373K as the nearest whole numbers ;)

For what it's worth, in the entire four years of a chemistry degree when I had to learn an unpleasant amount of stuff about thermodynamics and quantum mechanics, from people with much more of a flair for the subject that me, no-one ever once used the .15  :P

I'll admit that I ignore it as well. However, in this post... couldn't resist! :-\ :P

Good luck finding some equipment able to heat to that degree of accuracy ;)

I've previously used a heating block (for epi tubes containing my DNA, in case anyone is interested!) which was accurate to ^0.3K.  I think it only cost around ^500, so I'd imagine there must be more accurate equipment on the market.

I'm not quite sure how we've managed to deviate from the Turbo refresh to discussion of accuracy in laboratory heating blocks  ??? ::) :P

The equipment on FGW's Thames Turbos could do with being accurate to ^10K, let alone several orders of magnitude lower! :o

Oh really **art ****, maybe Hydrogen Hydroxide has a melting point of 273K (0C) but the Boiling point Varies upon pressure. In a Vacuum melting Hydrogen Hydroxide Boils at 273K (0C)

Where I live Hydrogen Hydroxide (I'll call it water from now) boils at around 371.5K (98.5C) due to the slightly lower air pressure here!



Edit note: Quote marks amended. CfN.

So what you are saying is how hot a cup of FGW coffee i depends on where on the route you buy it



Edit note: Quote marks amended. CfN.

You're right, I am so terribly sorry to have caused offence. Time I handed the PhD back, I've obviously forgotten it all ;)

I neglected to mention that the quoted melting/boiling points of water applie to a standard pressure of 1 bar, or 760 mmHg. It would have taken me a little while (not to mention a significant amount of stalking) to list the different boiling temperatures at the altitude where each different coffeeshop member lives. And in fact it will vary slightly from one day to the next due to changes in atmospheric pressure, so I doubt it's boiling at 98.5C every day at smokey towers. It'll boil slightly lower on a day with low pressure and higher on a day with high pressure.

For the sake of accuracy there will be a very, very, very, very tiny variation in the freezing point of water with pressure since there is a volume change during the phase transition given the hydrogen-bonding networks that form in the solid, meaning that ice actually has a slightly larger volume than liquid water (which is why frozen pipes burst, and is one of water's very unusual chemical properties. The volume change between liquid and solid is normally to all intents and purposes negligible, but with the solid taking up an infinitesimally smaller volume than the liquid).

Better?  :P

So you live at 1500 feet above sea level?

Off topic - have you ever tried boiling potatoes at 10,000 feet ... they take an age - especially after a day's skiing!

Erm ... The highest point anywhere in Cornwall is (if you'll pardon the expression) Brown Willy (http://en.wikipedia.org/wiki/Brown_Willy), at 1,378 feet above sea level.  ;) :D ;D

I'm guessing that the type of water being boiled is also a factor. Tap water has various minerals in it that will affect it's boiling point.

If I remember my schoolboy chemistry correctly 100^C is the boiling point of pure water at standard conditions for temperature and pressure (STP).