Author Topic: UK back to "imperial" measurements ?  (Read 15261 times)

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Offline PlainName

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Re: UK back to "imperial" measurements ?
« Reply #125 on: June 02, 2022, 12:12:09 pm »
Quote
I remember having to do far too many LSD[1] calculations in school arithmetic lessons. Life's too short for that crap.

But it did help to stave off a sedentary mind.
 

Online tggzzz

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Re: UK back to "imperial" measurements ?
« Reply #126 on: June 02, 2022, 12:16:40 pm »
I must be an American thing. It's such an easy thing to program. My kitchen scales can even be set for pounds and ounces, although the resolution drops from 0.05oz to 0.1oz on the pounds setting, because the display doesn't have room for the extra decimal place.

I don't think it's entirely about programming. It would be so confusing. Suppose your receipt said this: "0 lb 8.5 oz at $8.99/lb thus $4.76"

Can you imagine the confusion? How could you ever check whether you had been charged the correct amount without a calculator?

The reality is that America is decimal, and has been for quite some time.

In engineering, weights are in pounds (lb), thousands of pounds (Mlb), or millions of pounds (MMlb).

Distances are in feet, hundreds of feet, or thousands of feet. Road signs will say "500 ft" when giving a distance to a hazard.

Also in engineering, measurements are in inches and thousandths of an inch (mils). The dimension of a part will be given as 2.351 inches. Pins on ICs or headers are 0.1 inches apart.

It makes sense. Decimal is the only sensible way to make measurements and do calculations.
Why not use ounces? I personally fine 1.25lb more confusing than 1lb 4oz or even 20oz. I'm pretty sure things were sold in pounds, as well as ounces before the UK went metric.

Because I always forget whether I should be using base 14 or base 16 arithmetic.
Then why not simply go metric instead of using decimal imperial, which is more confusing?

I do normally use metric, especially where arithmetic is necessary.

I don't use metric when checking my weight daily, although I do for other purposes. I still tend to think in terms of a portion of meat being 4oz, but anywhere from 100-150g is an acceptable approximation.
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Online tggzzz

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Re: UK back to "imperial" measurements ?
« Reply #127 on: June 02, 2022, 12:20:00 pm »
Quote
I remember having to do far too many LSD[1] calculations in school arithmetic lessons. Life's too short for that crap.

But it did help to stave off a sedentary mind.

Only if you have an indolent mind that lies dormant until necessary!

Back then I was far too interested in cyphers, electronics, making things to have an indolent mind :)
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Online IanB

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Re: UK back to "imperial" measurements ?
« Reply #128 on: June 02, 2022, 05:30:33 pm »
Hmm, nope.
In Engineering, weights are in Newton (N), lengths are in meters (m)
Even in the USA.

You are being funny, of course.

But while it is true that a mix of units is in use, depending on discipline, and while it is true that engineers understand SI units, it does not mean that SI units are in any way standard across disciplines. It is also the case that "weight" is a common synonym for mass, and will be used as such even in professional exams where the context is clear.

Here's one example among many you can find where customary units are in use:

https://www.pegenius.com/civil-pe-review-daily-questions

(I just learned to my amusement that while "Mlb" is a common abbreviation for one thousand pounds mass, "kip" is an abbreviation for one thousand pounds force.)

Here's an example (attached) from an FE practice paper. It shows that even today students are being taught to deal with these kinds of units. From a European perspective this feels rather strange.
« Last Edit: June 02, 2022, 05:32:06 pm by IanB »
 

Online Kleinstein

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Re: UK back to "imperial" measurements ?
« Reply #129 on: June 02, 2022, 05:57:53 pm »
The simple imperial units are relatively easy, but I really don't like BUT/sq. ft * inch / °F for thermal conductivity.

I don't think the UK would really more back to the imperial system, maybe a slight slow down in finally getting rid of the rests of the imperial system.
 

Offline mclute0

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Re: UK back to "imperial" measurements ?
« Reply #130 on: June 02, 2022, 06:08:29 pm »
So just for fun, and in the spirit of inclusivity and human/universe coexistence, I think we need some new standards of measurement that are universal and not based on human truths.

Why do I say this? I really like the Asimovian idea that at some point, maybe a megaannum from today, we will meet other intelligences and if out systems are based on universal truths our ability to communicate will be much improved.

What do I mean by universal? I would perhaps start with say the wavelength of the first spectral line of Lyman series for Hydrogen as the base unit of measurement of distance.

Is that the best we could do? Probably not, but it gives you the idea. What we call the measurements is not nearly important as the understanding of their context. Like using base 2 with computers and not human centric base 10, adapting to a new system is only more mathematics, but using that new system improves the related system of communication.

Just hope we don't meet the Mule.

I wonder if Asimov would have done TikTok.

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Offline free_electron

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Re: UK back to "imperial" measurements ?
« Reply #131 on: June 02, 2022, 06:17:39 pm »
So the new unit of voltage is pound times square inch per coulomb per square second? I will try to remember ;D
Is there an imperial unit of charge I forgot about?
seconds need to be defined in fractions of fortnights...
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Offline TimFox

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Re: UK back to "imperial" measurements ?
« Reply #132 on: June 02, 2022, 07:12:00 pm »
There is a "customary" unit for magnetic flux density (B-field):  lines/in2.
1 line/in2 = 15.5 uT.
(The "line" corresponds to the old cgs unit "Maxwell" or Mx)
In older electrical engineering, one can find "Mx/in2" and "Wb/in2".
In modern SI, 1 T = 1 Wb/m2 is the preferred name for magnetic flux density or "magnetic induction" B.
In rationalized units, the other field H in A/m is called the "magnetic field", just to confuse people.
 

Online IanB

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Re: UK back to "imperial" measurements ?
« Reply #133 on: June 02, 2022, 07:27:44 pm »
In rationalized units, the other field H in A/m is called the "magnetic field", just to confuse people.

If I envisage a long, thin, straight conductor in free space, and I want to consider the magnetic field strength in the proximity of that wire, then the only two considerations are the current in the wire, and the distance from the wire. The magnetic field increases with current, and is presumably proportional to the current, so it is "A times something". The magnetic field decreases with distance from the wire, so we will be dividing by distance. At the simplest we therefore have "A/m".

What is the intuition that tells is it is A/m rather than, say, A/m2 ?

The best I have is that the inverse square law typically applies to distance from a point source (zero dimensions). Since in our case we have a long straight wire (one dimension instead of zero dimensions), the inverse square law loses a dimension and becomes a simple inverse.
 

Offline TimFox

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Re: UK back to "imperial" measurements ?
« Reply #134 on: June 02, 2022, 07:33:39 pm »
That's as good an "intuitive" explanation as any.  Another explanation is that if you do a line integral of H along a closed curve, it equals the total current (in Amp-turns) crossing the 2D surface enclosed by the curve.
In electromagnet design, H is often measured in "Amp-turns/meter" for that reason.
The difference between "rationalized" units, including modern SI, and "unrationalized" units, such as "Gaussian" cgs is where to put the 4 pi in the equations.
In Gaussian units (preferred by some physicists who don't own Simpson 260 meters), B and H are in the same units (Gauss), although H is sometimes called out as "Oersteds", even though that equals the Gauss.
In "rationalized mks" (SI) units, they are related in vacuum by B = (4pi)x10-7 x H, where the factor (permeability of free space) is an exact constant that defines the Ampere through the other equations.
« Last Edit: June 02, 2022, 08:05:12 pm by TimFox »
 

Offline Terry Bites

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Re: UK back to "imperial" measurements ?
« Reply #135 on: June 05, 2022, 03:04:16 pm »
I have seen this discussion in What Bollocks magazine.

I'm sure us Brits would love to use cubits per salck cullishigay . Lots of old codgers (not me, obviously) and our legion morons would like to go back to the sixties when LSD (£sd) was real money.
We'd need to get off those milligrams while we're at it. I'm going make my apothecary weigh it out in grains while I watch. He said "Would you prefer the liquid formulation, 6 carats per drachm? "
I struck him for his insolence of course!

Soon I expect the tori grandees to consider adopting the gold standard and making rickets compulsory.

 

Offline Terry Bites

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Re: UK back to "imperial" measurements ?
« Reply #136 on: June 05, 2022, 03:14:14 pm »
Skeggy OMG. Too many wasted childhood hours. I know a bloke who lives in the middle another town of Lincoln county - Scunthorpe.
 

Offline TimFox

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Re: UK back to "imperial" measurements ?
« Reply #137 on: June 05, 2022, 03:58:23 pm »
I remember (late '60s) ordering from an ad in Wireless World to a UK firm for delivery to the US, when the Carolingian currency denominations were still in use.
At that time, the exchange rate was 1 GBP = 2.40 USD, which made the conversion very easy if I just converted the UK price to pence.
Long before credit cards, I went to my local small-town bank for a bank draft, payable in sterling.
At that time, banks were still independent, but small banks used a "correspondent bank", in this case Chemical Bank of New York.
(Later, during the merger frenzy, Chemical Bank acquired several other large banks, but the successor used the most famous name of the group, Chase.)
The teller at the small-town (Iowa) bank referred me to a vice president, who filled out the draft by hand.
He mis-spelled shilling, confusing it with the Austrian schilling.
I was so embarrassed.
 

Online tggzzz

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Re: UK back to "imperial" measurements ?
« Reply #138 on: June 05, 2022, 04:55:44 pm »
I remember (late '60s) ordering from an ad in Wireless World to a UK firm for delivery to the US, when the Carolingian currency denominations were still in use.
At that time, the exchange rate was 1 GBP = 2.40 USD, which made the conversion very easy if I just converted the UK price to pence.
Long before credit cards, I went to my local small-town bank for a bank draft, payable in sterling.
At that time, banks were still independent, but small banks used a "correspondent bank", in this case Chemical Bank of New York.
(Later, during the merger frenzy, Chemical Bank acquired several other large banks, but the successor used the most famous name of the group, Chase.)
The teller at the small-town (Iowa) bank referred me to a vice president, who filled out the draft by hand.
He mis-spelled shilling, confusing it with the Austrian schilling.
I was so embarrassed.

I did almost the same, but in reverse. I orderer new-fangled 0.5" LEDs from California, and had to get a special international money order.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline rfclown

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Re: UK back to "imperial" measurements ?
« Reply #139 on: June 05, 2022, 09:33:33 pm »
I grew up in the US with our goofy units. I was told as a child that we were going to convert to the better way... but it never happened. With our tools (nuts and bolts) we have a mix, so I have to have both English and metric wrenches and socket sets, which is a pain. I prefer when the socket is metric and I don't have to figure out if 9/32" is bigger than 16/64" (as opposed to 7mm vs 6mm) when I rummaging for the next bigger or smaller socket. For nuts/bolts, it would be nice if things were all metric... except that I'm an RF guy and I use mostly 3.5mm (SMA) connectors which have 5/16" nuts. Aaagggghhhh!

What I never understood was kg, which is mass, but used as force (weight). Why was that done wrong? If you're going to make us switch to different units, don't make it wrong units. At least in our goofy units we didn't weigh is slugs. When I see pressure gauges with kg/cm2 scales I want to throw them across the room. I guess we can't expect to make people to change when they've done the wrong thing too long. And then those same people throw stones at those who are using old goofy units.
 

Offline bd139

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Re: UK back to "imperial" measurements ?
« Reply #140 on: June 05, 2022, 09:48:45 pm »
Kg was never used as a force. Force is N (newtons)
 

Offline TimFox

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Re: UK back to "imperial" measurements ?
« Reply #141 on: June 05, 2022, 09:50:00 pm »
I grew up in the US with our goofy units. I was told as a child that we were going to convert to the better way... but it never happened. With our tools (nuts and bolts) we have a mix, so I have to have both English and metric wrenches and socket sets, which is a pain. I prefer when the socket is metric and I don't have to figure out if 9/32" is bigger than 16/64" (as opposed to 7mm vs 6mm) when I rummaging for the next bigger or smaller socket. For nuts/bolts, it would be nice if things were all metric... except that I'm an RF guy and I use mostly 3.5mm (SMA) connectors which have 5/16" nuts. Aaagggghhhh!

What I never understood was kg, which is mass, but used as force (weight). Why was that done wrong? If you're going to make us switch to different units, don't make it wrong units. At least in our goofy units we didn't weigh is slugs. When I see pressure gauges with kg/cm2 scales I want to throw them across the room. I guess we can't expect to make people to change when they've done the wrong thing too long. And then those same people throw stones at those who are using old goofy units.

Yes, in metric countries engineers often (incorrectly) express force in "kgf" instead of Newtons.
In US customary units, the "lb av" is often used (incorrectly) as a unit of mass, although technically it should be a unit of force and weight.
Specifically:  when the local consumer-department inspector checks the setting on a sales scale, he places a known artifact on the scale to check the reading.  The marking on that calibration mass assumes a standard gravitational acceleration value (roughly that at sea level at 45o latitude) to know the actual weight at that standard location.  (NIST considers that acceleration value to be a defined constant, like 1 in = 2.54 cm exactly.)
However, he will use the same set of reference weights in Denver as in New York, even though a pound of steak transported to Denver weighs less at high altitude.  (Don't go into your local grocery store and ask for slugs--they might have a weird imported food section.)
I find it hard to believe that you can't quickly determine that 9/32 = 18/64 is larger than 1/4 = 16/64.  We live in a binary world.
I own two sets of sockets from Sears, one for inch and one for mm, that both have 1/4 inch drive.  Each set fits nicely into its small rack.
Owning a full set of US number drills, letter drills, and fractional-inch drills means that I can get close enough to any mm size.
 

Offline TimFox

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Re: UK back to "imperial" measurements ?
« Reply #142 on: June 05, 2022, 09:50:49 pm »
Kg was never used as a force. Force is N (newtons)

You have never seen a pressure gauge calibrated in kg/cm2 or kgf/cm2?
Do they only export those gauges to the US?
 

Offline eti

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Re: UK back to "imperial" measurements ?
« Reply #143 on: June 05, 2022, 09:51:29 pm »
Source -> https://www.mirror.co.uk/news/politics/boris-johnson-bids-jubilee-boost-27090524

Quotes :

... BoJo is planning to announce that imperial measurements will be revived to mark the Queen's Platinum Jubilee...

... the move represents a victory for 'metric martyrs' it is a largely symbolic one to address gripes about EU interference in traditional English life. ...  ???

Oh "THE MIRROR"? Well in that case it MUST be true...  :palm: The cheapest brand of novelty printed toilet roll.
 
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Offline bd139

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Re: UK back to "imperial" measurements ?
« Reply #144 on: June 05, 2022, 09:55:36 pm »
Kg was never used as a force. Force is N (newtons)

You have never seen a pressure gauge calibrated in kg/cm2 or kgf/cm2?
Do they only export those gauges to the US?

That’s a pressure not a force. And it should be pascals.
 

Offline TimFox

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Re: UK back to "imperial" measurements ?
« Reply #145 on: June 05, 2022, 09:57:11 pm »
Source -> https://www.mirror.co.uk/news/politics/boris-johnson-bids-jubilee-boost-27090524

Quotes :

... BoJo is planning to announce that imperial measurements will be revived to mark the Queen's Platinum Jubilee...

... the move represents a victory for 'metric martyrs' it is a largely symbolic one to address gripes about EU interference in traditional English life. ...  ???

Oh "THE MIRROR"? Well in that case it MUST be true...  :palm: The cheapest brand of novelty printed toilet roll.


I do remember this from a member of HM government:  https://www.politicshome.com/news/article/jacob-reesmogg-orders-staff-to-use-imperial-measures-and-double-spacing-in-leaked-memo
and the colourful version from the Financial Times:  https://www.ft.com/content/e0556f76-afc6-11e9-8030-530adfa879c2
I don't disagree with his attempt to ban the usage "to meet with", however.
 

Offline TimFox

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Re: UK back to "imperial" measurements ?
« Reply #146 on: June 05, 2022, 09:59:57 pm »
Kg was never used as a force. Force is N (newtons)

You have never seen a pressure gauge calibrated in kg/cm2 or kgf/cm2?
Do they only export those gauges to the US?

That’s a pressure not a force. And it should be pascals.

Yes, but pressure is a measurement of force per unit area.
Before the pascal was defined, the proper measurement in mks units was N/m2, or dyne/cm2 in cgs.
1 Pa = 1 N/m2.
 

Offline tooki

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Re: UK back to "imperial" measurements ?
« Reply #147 on: June 05, 2022, 10:04:36 pm »
Kg was never used as a force. Force is N (newtons)

You have never seen a pressure gauge calibrated in kg/cm2 or kgf/cm2?
Do they only export those gauges to the US?
Probably. At least in Europe, it’s really not used any more. Germany apparently outlawed it in 1978.
 

Online IanB

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Re: UK back to "imperial" measurements ?
« Reply #148 on: June 05, 2022, 10:52:09 pm »
What I never understood was kg, which is mass, but used as force (weight). Why was that done wrong? If you're going to make us switch to different units, don't make it wrong units. At least in our goofy units we didn't weigh is slugs. When I see pressure gauges with kg/cm2 scales I want to throw them across the room. I guess we can't expect to make people to change when they've done the wrong thing too long. And then those same people throw stones at those who are using old goofy units.

Yes, in metric countries engineers often (incorrectly) express force in "kgf" instead of Newtons.
In US customary units, the "lb av" is often used (incorrectly) as a unit of mass, although technically it should be a unit of force and weight.

Kg was never used as a force. Force is N (newtons)

Oh boy  :palm:

Weights and measures is a convention. What is correct depends on your local culture and custom. To argue otherwise is like arguing that green beans are fruits and it is wrong for people to call them vegetables. Why would anyone give you the time of day?

So yes, the kilogram can be a unit of force, just like the pound. Hence the customary pressure unit of psi -- pounds (force) per square inch. Or the force unit of kip used by structural engineers -- kilo-pounds. Likewise, kg/cm2 is a common unit of pressure (somewhat universal in Japan and other parts of Asia, for example).

Would you go to Germany and insist they follow American customs because you are American and you think they should do things your way? I would hope not.

The pound, and the kilogram, obviously, are also used as units of mass. The key point being "used as". Thus, in engineering, you will find flows measured in MMlb/day (millions of pounds per day), and in other parts of the world you may find such flows measured in kt/day (thousands of metric tons per day).

Another foolish thing is arguing the difference between mass and weight. The world of commerce would fall apart if this were ever an issue. Are you going to question your 5 lb bag of rice because it might not contain 5 lb (mass) of rice?

Speak the language of the people you are dealing with and everything will be smooth. Speak a different language and they will look at you funny.
 

Offline TimFox

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Re: UK back to "imperial" measurements ?
« Reply #149 on: June 05, 2022, 11:10:58 pm »
I explained the legal meaning of a 5 lb bag of rice in a post above (reply 141).
In careful scientific and engineering usage, the kg is an SI unit of mass, the N is an SI unit of force or weight, and the lb av is a customary unit of force or weight.
What is correct is defined by statute.
What is common may be defined by custom.
 


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