[Closed] Metric after brexit?

We'll go further back, bring back rods, chains, furlongs and so on!

Doesn't matter. In 2021 we'll be back to bartering.

trade you four toilet rolls for a quart of goats milk?

We won't have any manufacturing so it will be irrelevant.

If you're only sources of national income are fish exports, raspberry jam, Stilton cheese and backhanders from Russian oligarchs, you don't need precise or logical measurement.

Now's not the time to get bogged down in detail and practicality like measurements. Just wait for the latest non threatening northern voiced radio advert telling us how we've left Europe and how we'll have to pay attention now going on our hols rather than coming and going as we pleased.

Bumble. Bluster. Bluff.

Give 'em an inch and they'll take a m...

I'll get my cloak...

I think the EU has historically been blamed for converting the UK to metric.

Except that’s bollocks, and we adopted the metric system in 1968, I gather encouraging the Commonwealth and Ireland to do likewise. They’ve all completed the job, we bottled it.

The Quitters can come and take SI units from my cold, dead hands.

@crikey Useless fact: the formal definition of an inch is 25.4mm and has been since at least the 1960s…

We're all joking, but at every turn the Tories surprise with their stupidity & Populist barrel scraping

FTFY - Give ’em an inch and they’ll take a m…....63360 of them

I love metric BUT.

Fractions aren't as daft as they sound. Dead easy add and subtract without getting into the o.oooo1 precision.

@joshvegas There’s nothing wrong with fractions, but plenty wrong with units that change subdivisions as you go from one to the next.

Plus, as a child of 1980s Scotland I wasn’t taught imperial measurements at school. I know what a kg looks like (as it’s about the same as a litre of Hartmann’s) but have no frame of reference for a lb, nor how many oz there are in it.

Didn't JRM tell his office personnel to only use imperial or something once The Party came to power?

Anyway, if you believe in imperial enough it will still be world beating and ultimately lead us to that great Moon Shot moment.

You must just believe.

JRM did, and I would suggest that anything he does should be used as an example of what not to do.

No.

Next question?

The irony is that the Cabinet is full of people in the age groups that never learnt Imperial units.

Imagine Priti Vacant trying to explain that 30cm is longer than 11 3/4 inches but shorter than 11 7/8th inches?

Bring back the groat; best unit of currency we ever had.
Closely followed by the Widow's Mite.
I have a very old 'ready reckoner' from my grandfather, I think, and in there is an approximate weight calculator for animals going to market based on height/length/girth.
The tax calculators are great - but slightly outdated.

I have a very old ‘ready reckoner’ from my grandfather, I think, and in there is an approximate weight calculator for animals going to market based on height/length/girth.

Ooh, I've got something similar for gestation periods.

There’s nothing wrong with fractions, but plenty wrong with units that change subdivisions as you go from one to the next.

Oh aye totally.

That dial reminds me of being a kid, when we used to go visit my grandparents we used to drive past a factory that made 'animal identification systems'

I later learned it was ear tags and the like, but my Dad convinced me it was flow charts for farmers - does it have 4 legs? Is it as big as a big dog? Does it have wool? It's a sheep.

I couldn't fathom that men whose job it was to rear livestock didn't know horse from chicken without a system but it was my Dad telling me and therefore to a four year old, gospel.

Just putting this out here, but the biggest use of imperial* measurement is that there United States.

* obviously half of the US units are different sizes or amounts of volumes or whatever, when compared to original UK units.

but it was my Dad telling me and therefore to a four year old, gospel.

Top child rearing! Love it.

@Cougar - that looks well used. Did you use it to impress the ladies in pubs?

I couldn’t fathom...

Excellent work, Sir, well done

Just putting this out here, but the biggest use of imperial* measurement is that there United States.

Yeah but even they don't use it completely. Science is still in SI and engineering is a mix.

Anyway which imperial system? When in Hong Kong there were some old ladies still sell some green veg in an old Chinese imperial measure.

my Dad again, but when he bought a new adjustable spanner justified it to me by claiming this one was his metric adjustable, the old one was imperial.

I can't fathom why anyone would plumb the depths by using imperial units. There's no mileage in it.

Being more serious, most of the world uses metric now including most of US industry so machine tools are (mainly) metric. That'll make it rather hard to go back to imperial units for proper work. I really don't want to have to dig out my 3/4 inch spanner rather than my 19mm on. I certainly don't want to start adding a few though to 3/8 inch for clearance.

I couldn’t fathom…

Excellent work, Sir, well done

That’s deep.

Yeah but even they don’t use it completely. Science is still in SI and engineering is a mix.

https://www.simscale.com/blog/2017/12/nasa-mars-climate-orbiter-metric/

I wouldn't put it past the shysters that brought us blue passports to go for some sort of re-imperialisation. Easy win in the culture wars era to make a big thing about "bring back the pound" or some such.

"Metric after Brexit" is a very satisfying title

"God on a quad" is equally pleasing

Considering the UK didn't fully adopt the full metric system, we still use many imperial units take the roads for instance, everything is still in miles. Do you think if we went back to imperial system everything would be changed, or we would end up with an even more mismatched system?

Even on the roads it's mixed. Speed limits and distances are in miles but other signs such as width restrictions and bridge heights vary seemingly on which way the wind blows.

We should completely ditch imperial and adopt metric. There are now 2 generations who don't understand the differences and use metric most of the time anyway

 most of US industry

No, sadly. Or maybe you could explain to my colleagues in NJ why they should adopt the metric system in order to process the materials we do that are exclusively measured in microns. F knows I've been trying for the past 20 years... 🙄

After Brexit we'll have a new measurement system, it's called the Boris, but no one will understand how it works.

I weigh individual bike components in grams and then quote the overall bike weight in lbs for some reason.

I also run in KM and ride in miles. Weird huh?

“Metric after Brexit” is a very satisfying title

“God on a quad” is equally pleasing

One sends my anxiety levels up to 11

The other puts me one notch (a metric notch) above hibernation

Ogmios for me (and for PM).

@Cougar - that Silcock Gestation Table; 'date of service' isn't the last time it was calibrated is it??

After Brexit we’ll have a new measurement system, it’s called the Boris, but no one will understand how it works.

Especially Boris.

After Brexit we’ll have a new measurement system, it’s called the Boris, but no one will understand how it works.

It won't work.

Or if it does, only in a half assed part time kind of way.

Aside from all that, I'd propose a new unit,

"The Boris"

being an amount of work, say, equal to around 1mJ.

I'm sure the rose tinted Spitfires over the white cliffs lot wold love it... even if they didn't have much of a clue what it was. I think most rational people would think that going back to teaching imperial measurements in schools now would laughable, but then again... with this lot.

Was it 1974 when they actually stopped teaching imperial? Just as JRB was starting school then, so if he uses Imperial it's for some faux nostalgic reason (or more likely he's just a **** who knows his audience). That's not to say that schools had taught imperial up to 74 and then made the change over-night, most had switched much earlier. Most people who were taught imperial are now reaching retirement and have 2 generations coming after them who think metric, that tide has loooong turned.

No, I think the thick as mince Sun readers will get all giddy about being able to buy "pintas" in glass bottles again, "pints of beer" and bendy Bananas because the EU banned all those things didn't they?

As for our Yank friends, don't think they haven't got a clue what Metric is, the ones I know use both, they're not an insular as you might think. They don't have a full understanding - weirdly it's Temp they seem to struggle with, my SIL just couldn't get that 0c was freezing, 100c was boiling and a decent guess in between. To her 30c was cold, but she understood litres and had a better grasp of Kms than I do. Also, if you think you'll need an Imperial socket set to work on an American car, you'd be wrong. They've used metric fixings for years and I'm not just talking about the ones they sell here, but cars they sell in the US as well.

There's actually a good argument why Fahrenheit is easier for the general public to understand. If you say today it will be sunny with low 70s, or high 70s, that's easy to grasp and there isn't a huge difference between them. One is pleasant, the other is a bit hotter.

If you use deg C, then say today it will be in the 20s, it doesn't work as well. 20C is nice, 29C is chuffin hot. People are simple, deg F is easier for most people to understand for weather. For other stuff it gets less useful very quickly!

Go do some work in the oil industry in the US (all imperial) then go to Canada and see the horrible miss mash they have. Deca Newton for force, sacks for powered goods, bar for some pressures psi for others. Barrels for fluid volumes (of course this the oil industry) litre for other fluid volumes.

easier for the general public to understand

which is often the reasoning behind old units, I think

inches were handily close to fingertip/knuckle
yard, average stride
foot, your imagination can run riot

agricultural units
how much field can you plough with an ox in one day, that's an acre
one ox goes for one furlong before it needs rest, 220 yards
one oxgang, that's a limit on your farm size if you have just one ox, about 15 acres
and there's a bazillion* more of those

* not an imperial measure

If you say today it will be sunny with low 70s, or high 70s

If you use deg C, then say today it will be in the 20s, it doesn’t work as well

Er... taking you first example... "low 20s", "mid 20s" or "high 20s"... or... now you may think this is crazy... "about 22", or a more real example... "temperatures could reach as high as 28 degrees today in some areas, with night time lows of about 6 degrees". And why include the helpful "sunny" in the F example, and no similar qualitative language in the C example?

I'm 45. People of about my age may well remember this toy:

When I was very little I remember asking my dad what the "inch" scale on the ruler was about, and was met with a reassuring "oh it's an old measurement that you kids won't need to know about." Well, that certainly hasn't been the case.

I've ended up fluent in both Imperial and metric distance measurements, and a spell working at the fish counter and in the meat department in the local supermarket as a teenager gave me a bit of an idea of pounds and ounces (a pound is a good handful of mince, or haddock), as has baking cakes using recipe books I got from my mum. Other than that I'm probably mostly metric.

I certainly don't "get" the Fahrenheit scale, while it may seem intuitive to some it's just not as present in my day-to-day life as Imperial weights and distances are. I know what temperatures of low, mid and high 20s will be like, I have no clue how they equate to Fahrenheit temperature.

I'm certain though that a certain grumpy old sort will have seen Brexit as meaning a glorious return to buying their fruit and veg in ponds and ounces, though.

All the common imperial units are now actually derived from metric.

An inch is fixed at exactly 25.4mm, which makes a yard exactly 91.44cm and so on.

The pound is similarly defined as a precise number of grams.

I think the UK is fairly unique in using the two systems interchangeably.

Bikes are pretty bad for throwing together a mix of imp / metric: Your cranks are 170mm but the pedal treads are 9/16th. Your 150mm travel forks use a 1.25 to 1.125 inch steerer.

Cars and motoring are even worse though.

You drive a mile to fill up the car with 40 litres of petrol. On the way there you get 35mpg. Your engine has 247hp and 420N/m of torque. When you buy tyres they are 18" x 235mm. Stopping distances, height restriction and the space you should give a bike in the highway code are all in meters, but all speeds are still in mph.

Fractions aren’t as daft as they sound. Dead easy add and subtract without getting into the o.oooo1 precision.

Indeed, well, until you need to be more accurate than 1/16 or 1/32 anyway.

Because machining a crank down to 20/20 is so much easier when you have to do 1 13/16 minus 20/1000 in your head compared to 46.00-0.05.

And that's before you get into the quagmire of whitworth Vs UNC threads and spanners.

Your 150mm travel forks use a 1.25 to 1.125 inch steerer

But do they? I mean is the steerer tube actually made to an imperial measurement with a tolerance expressed in imperial or is it, in fact just commonly referred to as 1.25 inches but all the manufacturing, QA etc happens in the metric equivalent?

I may be splitting hairs, but isn't this just an anomaly unlike 27.2 seatposts where it's now expressed in mm, the forks are just a still described using "old money" but actually made to metric measurements? Genuine question from a pedant 🙂

@kelvin - I was just repeating a recent conversation with a US colleague (answering why they like using it)

PS with your name you're views are biased anyway !

There’s actually a good argument why Fahrenheit is easier for the general public to understand. If you say today it will be sunny with low 70s, or high 70s, that’s easy to grasp and there isn’t a huge difference between them. One is pleasant, the other is a bit hotter.

If you use deg C, then say today it will be in the 20s, it doesn’t work as well. 20C is nice, 29C is chuffin hot. People are simple, deg F is easier for most people to understand for weather. For other stuff it gets less useful very quickly!

That's familiarity, and is completely subjective. I haven't used Fahrenheit for years, and I couldn't tell you when the 70s go from pleasant to hot - I know both 71 and 79 are t-shirt weather, but that's about it.

When I was at university in the 80s doing mechanical engineering, one of the labs revolved around a hydraulic pump coupled to a hydraulic motor with some other bits and pieces. All the gauges used a mixture of different units. It was pretty much impossible to do the calculations - we all complained to the lecturer the next day. He had a good laugh - the whole point of the lab was to show how difficult it is mixing units, he wasn't really worried about us getting the calculations right.

I feel for anyone mixing imperial and metric. Thoughts and prayers.

There’s nothing wrong with fractions,

In the States, Wendy's introduced the 1/3 pounder burger, one upping McD's 1/4 pounder. It sold terribly, as people thought it was smaller.

The usability of the units individually depends entirely on your life experience as to whether you find a foot or a pint to be easy to visualise.

the benefits of metric is the interlinking. A 100mm cube of water is a litre, which weighs a kilo. A metre cube of water is a tonne if you are thinking bigger. Everything else you can reckon up with a basic estimate of linear distance, and density compared to water.

These are the useful ones for life, temperature and energy and so on are linked too.

But do they? I mean is the steerer tube actually made to an imperial measurement with a tolerance expressed in imperial or is it, in fact just commonly referred to as 1.25 inches but all the manufacturing, QA etc happens in the metric equivalent?

Yeah no doubt, especially given than inches are precisely defined in millimeters.

So 1.25" is exactly 31.75mm and 1.125" is exactly 28.575mm

Whether they actually round to 31.8mm and 28.6mm to meet the "standard" I don't know

I was just repeating a recent conversation with a US colleague

Well we all understand "sunny" better than just some numbers.

with your name you’re views are biased anyway !

It's 284K here today. I can see how that's much less intuitively useful than 11˚ (and less friendly than "in the low 50s"),

the benefits of metric is the interlinking. A 100mm cube of water is a litre, which weighs a kilo

and "a pints a pound the world around" - at least in the USA

I mean is the steerer tube actually made to an imperial measurement with a tolerance expressed in imperial or is it, in fact just commonly referred to as 1.25 inches but all the manufacturing, QA etc happens in the metric equivalent?

It probably depends where the factory is.

We make and export stuff worldwide, and the 'language of the factory' is metric. Many US customers send us imperial drawings which we re-draw in metric for manufacture (taking into account that rounding isn't allowed for tolerances, which means that the metric tolerances edge in slightly). When we send them the parts, they will check them to the imperial drawing.

But contrarily, kph is idiotic. the per hour introduces a 3600 which is definitely not helpful for anything.

Using m/s on the roads would make sense, practical range from zero to 40m/s, gives enough spread that multiples of five are useful subdivisions, no danger of getting to 3 figures (ruining road signs, and the aethetics of digital speedometers).
Might make people think about stopping distances too...

I feel for anyone mixing imperial and metric. Thoughts and prayers.

I've spent my entire career, just about, in the oil and gas industry so I got used to converting units very early on. The best argument against the use of imperial units is that to do anything meaningful with any measurement the first thing you have to do is convert to a metric type unit.

That being said Base 12 or Base 64 number systems have a lot to recommend them. Just a shame that imperial units don't use a consistent base number.

and “a pints a pound the world around” – at least in the USA

even in every country where its not, its a good approximation, but what happens when pints and pounds are not scale appropriate. How many ounces in a gallon?

Yea, not buying Fahrenheit being easier either.

There's actually some research done somewhere that determined people like scales around 30.

30kg is as much as you can sensibly carry
30C is a hot day
30 miles is (a bit longer) than a marathon
30meters is about as far as healthy eyes can read a number plate
30psi in your tires

Given several sets of units, people tend to settle on the one that puts 'normal' at about 30. E.g. at work I use all sorts of pressure units (kpa, bar, psi) but generally know the conversions to bar in my head as bar tends to be the one that gives you numbers that are 1-100 rather than 100,000.

But do they? I mean is the steerer tube actually made to an imperial measurement with a tolerance expressed in imperial or is it, in fact just commonly referred to as 1.25 inches but all the manufacturing, QA etc happens in the metric equivalent?

A 1.1/8 steerer is imperial (28.6mm) . But the bearing race at the bottom is metric(30mm).

A 1.1/8 headtube is 34mm though.

A 1.5 steerer is the same, 38.1mm, but 40mm where the bearing sits and a 44mm headtube. Then it all gets complicated as they add/subtract 0.1mm to achieve a tight fit!

How many ounces in a gallon?

Us or imperial?

Anyone who thinks metric has basically taken over and Imperial units are just used out of habit are delusional. If somone can do a quick search for 12.5 micron shim I could do with a bit right now...

Kpsi commonly used in our industry 😄🙄

I feel for anyone mixing imperial and metric. Thoughts and prayers.

The railways rang, they want a word.

ElShalimo
Free Member
“Metric after Brexit” is a very satisfying title

“God on a quad” is equally pleasing

But "God on a Cod" makes for a better mental image.

The Fahrenheit scale makes no sense though: Set 0 at the freezing point of Brine ( to some unspecified water/salt mixture, for reasons lost to history), and 96 (not 100 obviously, as that would be way to straightforward) as the approximate temp of a "healthy man"  (whatever that definition means, and a complete guess that turned out wrong anyway).

vs Celsius; 0 set at the point water freezes, and 100 at the point it boils...

Yeah, one seems slightly more intuitive than the other to me for some reason....

All the common imperial units are now actually derived from metric.

An inch is fixed at exactly 25.4mm, which makes a yard exactly 91.44cm and so on.

The pound is similarly defined as a precise number of grams.

Hang on...

So you think because you can convert one to another, they're derived from each other because it's "fixed at exactly" 1" = 25.4mm or 1 yard = 91.44cm and a Pound is defined as at a "precise" 453.592g.

In fairness when we're thinking about Imperial measurements, there may be some sense to that, no logic of course, but maybe it makes sense on some "it's the size of your Aunt Vera's big toe" Imperial measurement kind of way.

The Fahrenheit scale makes no sense though: Set 0 at the freezing point of Brine ( to some unspecified water/salt mixture, for reasons lost to history), and 96 (not 100 obviously, as that would be way to straightforward) as the approximate temp of a “healthy man” (whatever that definition means, and a complete guess that turned out wrong anyway).

The numbers were originally 1/4 of those values; nobody knows why Fahrenheit multiplied them all by 4 at some point. The numbers used were to do with factors and ease of divisibility - in the days before calculators using fractions made a lot of sense and it was originally devised by an astronomer who wanted 60th and 8th involved.

Good video here:

I've just rewatched the video and the Fahrenheit link to the expansion of mercury is interesting.

@ratherbeintobago

Plus, as a child of 1980s Scotland I wasn’t taught imperial measurements at school. I know what a kg looks like (as it’s about the same as a litre of Hartmann’s) but have no frame of reference for a lb, nor how many oz there are in it.

Well in those kind of approximations a lb is about 1/2 a litre of hartmann's (or a proper jar of jam) and there are 16 oz in a lb, which makes an ounce a smidge under 2 tablespoons of water.

do you describe your height and weight in kg and m? Bizarely despite being of the same era I still refer to humans in imperial...

Yes, describe my height and weight in metric. Why wouldn’t I?

Hang on…

So you think because you can convert one to another, they’re derived from each other because it’s “fixed at exactly” 1″ = 25.4mm or 1 yard = 91.44cm and a Pound is defined as at a “precise” 453.592g.

Imperial measures were originally derived from some physical, often human or animal definition. An inch is a 1/12 of a foot (inch being a rough translation of "twelfth" in Roman) and a foot was defined as well the size of a foot, exactly whose foot is lost to history.

But there were lots of competing definitions (there were Scottish feet, which were naturally a bit bigger)

In the 50's the Imperial measures were standardised and defined using precise metric measures. So they are now defined by metric measures and the metric SI units are all now derived from physical constants of the universe

Imperial measures were originally derived from some physical, often human or animal definition. An inch is a 1/12 of a foot (inch being a rough translation of “twelfth” in Roman) and a foot was defined as well the size of a foot, exactly whose foot is lost to history.

But there were lots of competing definitions (there were Scottish feet, which were naturally a bit bigger)

In the 50’s the Imperial measures were standardised and defined using precise metric measures. So they are now defined my metric measures and the metric SI units are all now derived from physical constants of the universe

Ah, I understand so pre 1950s imperial measurements weren't standardised. Thanks.

As a few people asked about the calculator on the previous page,

My first home when I was very young was a dairy farm. There's a few throwbacks from my grandparents still in this house, that was on the shelf under the stairs. I have no idea why, unless they kept it as a souvenir or curiosity.

I think the UK is fairly unique in using the two systems interchangeably.

I think we are, broadly, metric these days. Certainly for new stuff, it's legacy things that are killing us. Road signs for instance, the cost and labour involved in changing pretty much every single sign in the country would be astronomical and the benefit relatively minimal. Milk and beer is sold in 568ml servings, again the reason for this is pretty obvious - can you imagine the front cover of the Daily Express if we metricised the pint to 500ml?

There is still a small, gammony subset of the population still dreaming of halcyon days of pounds, shillings and pence and spending their retirements "correcting" footpath signs. But they're surely few and far between by now. Anyone under the age of 50 will have grown up all their lives being taught it, and much older than that and it's not like they've not had time to learn. It's wilful ignorance, the same attitude that would turn up their noses at anything other than meat & two veg as "foreign muck."

For me, being in my 40s I grew up with both, metric via school and imperial via (grand)parents. I'll favour metric but will use whatever's most convenient. Eg, I was measuring a drawer earlier this week, 407mm... oh, no, wait, it's 16".

Wendy’s introduced the 1/3 pounder burger, one upping McD’s 1/4 pounder. It sold terribly, as people thought it was smaller.

Missed a trick there, they should've changed nothing and called it the 2/8 burger.

This is happening with mobile phones now incidentally, have you noticed? Your standard widescreen ratio is 16:9, they're now doing ultra-wide screens at... 18:9.

and “a pints a pound the world around” – at least in the USA

Not even in the USA, it's an approximation. A pound is 454g, a US pint is 473ml. They're 20(ml|g) different.

vs Celsius; 0 set at the point water freezes, and 100 at the point it boils…

0'C is the melting point of ice, not the freezing point of water. I'm not really sure what the difference is, maybe there's a small gap or overlap, but my GCSE Physics teacher used to think it was important.

0’C is the melting point of ice, not the freezing point of water. I’m not really sure what the difference is, maybe there’s a small gap or overlap, but my GCSE Physics teacher used to think it was important.

My Science teacher used to say something like Water was as close to magic as could be found in real life because it didn't conform to many scientific norms. I'm sure he said 0c was the temp in which it could be found in all 3 forms, solid, liquid and gas.

He was however, a heavy drinker so... you know.

Yes, 0C is the triple point of water. He was right.

My GCSE memory is that it also contracts as it cools until about 4° or something where it starts expanding again. Or something. Great stuff, water.

EDIT : And that's why ice floats and fish don't die when ponds freeze.

Plus, as a child of 1980s Scotland I wasn’t taught imperial measurements at school. I know what a kg looks like (as it’s about the same as a litre of Hartmann’s) but have no frame of reference for a lb, nor how many oz there are in it.

A kilo isn't 'about the same as a litre,' it's exactly a litre (of water at any rate, I know not the density of whatever Hartmann's is).

This is the embuggerance of it all when people complain they don't understand metric. It's really not hard, I'm certain that in many cases it's rather they don't want to understand it.

For an approximation of what something 'feels' like, if you understand yards you understand metres. 100 metres up the road and 100 yards up the road are close enough for most practical purposes.

A kilo is 2.2 pounds. You don't know what 10kg is? It's 22lbs. Not good at maths then just double it, you'll be in the right ballpark. 7kg = 14lbs (plus a bit).

A mile is ~1.6km. Maths fail again? 5km is a smidge over 3 miles. I (hypothetically) ran the Manchester 10k last week. What's that gran, you don't know how far it is? It's six miles. (Plus about 400 yards but does that matter?)

Fahrenheit to Celcius. Most people I think know that the formula is C = (F-32) * 5 / 9, who's going to do that in their head? Converting say 76F, what's 220/9? But it's pretty easy to get accuracy to within 100ths of a degree (and I actually made this method up, I've no idea why it isn't taught anywhere). Subtract 32, add the result to itself shifted right one decimal place, halve the result. So as above, 76 - 32 = 44. 44 + 4.4 = 48.8. 48.8 / 2 = 24.4'C. [ The proper conversion comes out at 24.44(recurring)'C ]

Still too complicated? A fair approximation is to subtract 30 and halve it, you'll get within a degree or two if you're dealing in weather ranges. 76F - 30 = 46, /2 = 23'C.

Yes, 0C is the triple point of water. He was right.

Sorry, how do you get water vapour at 0'C?