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Imperial vs Metric

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Cheshirechappie

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Hmm.

Seems that metric is 'scientific', and imperial is 'human'.

It's a bit easier doing engineering calculations in metric units (speaking from long and sometimes bitter experience), so they have their place. But so do imperial units, including time. When the day can be divided as so many fractions of the time between one sunrise and the next, it's easier to get a handle on than multiples of the numbers of oscillations of a certain atom in a vaccuum, and distances being measured in the length of your foot, or multiples or divisions thereof, is likewise more readily comprehendable than the fractions of the distance between the Earth's pole and it's equator.

Thus, they both have their place. Personally, if I'm ever again called upon to undertake the calculations necessary to prove that a chemical plant piping system will survive an earthquake of a given magnitude, I'd prefer to do said calcs in metric and base 10. But I'd still prefer to work wood in feet, inches and tads, and finish the day somewhere around sunset, perhaps with with a contemplative pint.
 

Andy Kev.

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Please can someone now tell me something useful to put my mind at rest. I would like to get my head around what was there before the (assumed) Big Bang. Also how can I imagine infinitesimal space? I feel this is sucking me in.
Try this:


Cracking book although the equations should perhaps have a parental advice warning.

The problem is that before the big bang it would appear that all time and space was in the same dot, then time began. But there must have been something outside the dot … another dot i.e. another universe? This is what keeps clever people awake at night.
 

Phil Pascoe

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But as said, I'm just a simpleton, so you can keep all your beery and watery stuff thanks - mine's just a goodly-size (Imperial or Metric, I don't care) of Malbec. :)
Another bit of weirdness when we went metric - why wasn't a bottle of spirits left at 75cl - very nearly the same as it measured before, 26 fl.oz? It's an unnecessary problem if you're a licensed trade buyer as you have to work out the prices per cc of both bottles and litres (or 1 1/2ltrs). So much simpler if you could look and think instantly ah, the bottle's ten quid, the litre's £12.50 so it's cheaper, or the litre's £13.75 so it's more expensive.
 

TheTiddles

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The beauty of imperial is that it then uses divisions and multiples of feet in human terms e.g. a furlong is a furrow long (if memory serves that's the length of a ploughed furrow and it comes in at 220 yards). What this adds up to is that imperial has a very pleasant, villagey feel about it whereas metric is perfect for the cold, unimaginable distances of the cosmos and the equally unimaginable tiny spaces within atoms. It's sort of the difference between enjoying a pint while watching a cricket match on the green versus downing a mineral water while discussing this year's accounts.

Mine's a Guinness.
except it isnt, and hasn't been for over a century, as even before then, people knew that having something that variable was a bad plan in the new modern world of the early-19th century, it took another 75 years (and a big fire) to totally do away with it, as you‘ve said, it’s just at a way of dividing up a known standard as agreed upon by everyone. You could measure everything in otter‘s tails if you so desired, you might not find them on tape measures but thankfully they are exactly 34mm wide, at which point, you may as well skip a stage and just use the mm straight.

Aidan
 

AJB Temple

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Try this:


Cracking book although the equations should perhaps have a parental advice warning.

The problem is that before the big bang it would appear that all time and space was in the same dot, then time began. But there must have been something outside the dot … another dot i.e. another universe? This is what keeps clever people awake at night.
I find the more I study the less I understand. Back in the day I studied maths at PhD level and spent (ie wasted) a lot of energy theorising about infinity. There are numerous learned theories about the dot. The one I like best contrives that there is a huge expansion, followed by a huge contraction into a dot again (takes a while). There could be an infinite number of dots doing this - not necessarily at the same time (using "time" in its wider sense). But it still leaves me with "how did the dots get there?" and "are the dots contained by anything?"
 
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Andy Kev.

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I find the more I study the less I understand. Back in the day I studied maths at PhD level and spent (ie wasted) a lot of energy theorising about infinity. There are numerous learned theories about the dot. The one I like best contrives that there is a huge expansion, followed by a huge contraction into a dot again (takes a while). There could be an infinite number of dots doing this - not necessarily at the same time (using "time" in its wider sense). But it still leaves me with "how did the dots get there?" and "are the dots contained by anything?"
It seems to me that we have a choice of options to believe in. The problem with one of them is that being physical creatures in this universe, it is almost impossible for us to imagine and that is the Single Dot Hypothesis. How can we cope with the notion of all time and space being contained in one infinitely small dot? I think it very difficult because, being of this universe, while we can accept the existence of a dot, we instinctively say, "But there must be something outside the dot" and as far as I can see the SDH demands that there be nothing outside.

Therefore I tend to the Multiple / Infinite Dot Hypothesis but on the basis of nothing more than as a creature of this universe, I am not equipped to conceptualise anything else.

As a kid I came to the conclusion that infinity isn't worth bothering about because it is scuppered every time by two words: Plus One. I can accept that some things are infinite, time being the obvious candidate and space possibly running it a close second. However, as a definable working concept it's a bit of a non-starter.
 
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J-G

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Whilst we are discussing 'Imperial' as opposed to 'Metric' we are also limiting our discussion to the 'British Imperial' measures. On a wider front has anyone an opinion on the Russian Imperial system and whether that is more useful for some tasks than the Metric system?

In weight - 1 Rad is 14 Pud and a Korob is 7 Pud but a Berkovets is 10 Pud. 1 Pud is 40 Funt and a Funt is 96 Zolotniks whilst a Lot is 3 Zolotniks.

In Length - 1 Verst is 500 Sazhen, a Sazhen = 3 Arshen and an Arshen is 16 Vershok. There were 4 Chetverts to the Arshen but the Chetvert as also a liquid measure being a ¼ of a Bochka or 10 Vedro.

No wonder they came to their senses in 1917 when they changed to the Metric syatem !

I feel a quiz round coming on :)
 

J-G

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As a kid I came to the conclusion that infinity isn't worth bothering about because it is scuppered every time by two words: Plus One.
I remember very clearly that Infinity cost me a relationship 😄

Trying to explain the concept to someone who couldn't divide by 10 !!! Yes, she couldn't use metric, the idea of cutting a round cake into 10 portions was beyond her comprehension.
 

bjm

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Please can someone now tell me something useful to put my mind at rest. I would like to get my head around what was there before the (assumed) Big Bang. Also how can I imagine infinitesimal space? I feel this is sucking me in.
I was listening to a scientist recently who said that when explaining theories, such as Quantum Mechanics, there comes a point where words fail to make sense and only the maths becomes plausible. The only problem with that explanation is that very few people, including mathematicians, can claim to grasp these constructs. Accept it/deny it - that's your choice?
 

AES

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@J-G: " ........... the idea of cutting a round cake into 10 portions was beyond her comprehension."

I can't see why that would be a problem if there was only the two of you :)

(Yup, I'm determined to keep this thread right down at the - low - level that I maybe understand) :cool:
 

bowmaster

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You seem to be picking on one part of the meaning of the word "metrically" - the use of "metric prefixes" like nano. You can use metric prefixes with any system (look at the thou for an example - effectively one milli-inch). That is only one part of the metric system; another very important one being the concept of Coherence, which to my understanding basically means that you very rarely need arbitrary constants when performing calculations. For example, a watt is one joule per second whereas a horsepower is 550 foot-pounds per second.

The second as a unit is metric in the sense that it is a fundamental part of the metric system of units known as SI and is coherent with the other metric units. It is now defined in terms of things that don't change anywhere in the universe, as are all elements of the metric system (and other elements like the inch that are defined in terms of the metric system).

All units are arbitrary in that you have to pick a number to start with. The fact that the metre was initially picked as a (not very accurately measured) part of the earth's circumference, the second was picked as part of a day and the foot was picked as the length of someone's foot is irrelevant. The derived units are arguably more important as things like the watt are simple whereas things like horsepower need conversion factors.

Imperial units might well be better for measuring furrows but for most things that any of us are going to use in a workshop, there's no fundamental difference in what the two systems are capable of. The inch and the millimetre are based on the same standard (the metre) after all. Whether you prefer working to millimetres or 1/32", or prefer microns or ten-thousandths of an inch is arguably personal preference, although having multiple systems of units in the world (and even just in this country) makes things more difficult for everyone.

The metric system is objectively better for scientific use and having two systems undoubtedly increases confusion, as does the imperial system's habit of switching between fractions and decimals arbitrarily - I've seen mechanical drawings with instructions like 'drill with a #6 drill, then bore to 0.240", then ream 1/4" '. I for one would much rather see 'drill with a 5.2 mm drill bit, then bore to 5.8 mm, then ream 6 mm". Similar comments can be made about material thicknesses in AWG or SWG. I would be much more in favour of inches if they were used consistently.

One thing I will say in favour of imperial stuff is that quite a few of the imperial conventional sizes (with lots of exceptions of course) are slightly bigger than the metric equivalents. That means if I buy a bit of 1" stock and stick it in the lathe, I can turn it down to 25 mm and guarantee concentricity with diameters. If I'd bought 25 mm stock, that wouldn't be possible!

I also think there's a special place in hell reserved for people who quote temperatures only in Fahrenheit...



I'll have 50 ml of Springbank.
I'm off to speak to my accountant......
 

bowmaster

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You learn something every day.

@ J-G I'd not heard the equator to N Pole thing before and that is of course also necessarily arbitrary. Agreed about basing the metre on the absolute constant of the speed of light (in a vacuum?) but am I not right in thinking that it still does no more than precisely define in absolute terms the the length of the arbitrary metre. We could just as easily determine the foot in terms of the speed of light but it would be no less arbitrary. I'm not suggesting that arbitrary is in any way inferior but the more I think about it, the more arbitrary units of measurement seem to be unless the unit of measurement is itself an absolute e.g. the mass of a proton.

@Dr Al I agree with all of that. I do however, have the impression that metric is presented as being somehow superior. It can't be of Course, as we agree that all units of measurement are arbitrary. What it undoubtedly is, is mathematically more convenient, especially for physicists, engineers etc. The woodworker has a choice of which system he finds to be more convenient. I tend to prefer imperial for woodwork because it seems natural to consider halves, quarters, eighths of units (in this case the inch) for practical purposes. Obviously other people prefer metric. I was brought up with both systems and have come to prefer imperial for the real world and metric for when e.g. I'm trying to understand astronomy or nuclear physics.

Isn't the real problem time? (Genuine question.) We're not quite sure what it is and it is - almost incredibly - relative due to the famous speeding up/slowing down aspects of it for high speed space travellers.

@Droogs I refuse to offer an opinion on black holes until I've heard Paul Sellers on the topic. Also Einstein was not known for his mortices and tenons which does of course cause the thinking man to raise an eyebrow.
Who knows what Einstein did dressed in a leather apron on a weekend in a darkened room - only he knew <lol>
 

bowmaster

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Try this:


Cracking book although the equations should perhaps have a parental advice warning.

The problem is that before the big bang it would appear that all time and space was in the same dot, then time began. But there must have been something outside the dot … another dot i.e. another universe? This is what keeps clever people awake at night.
If time is an unknown phenomenon (introduced by man to rationalize about changes from one event to another) then how can we say that time began at the moment of the big bang?
 

Andy Kev.

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If time is an unknown phenomenon (introduced by man to rationalize about changes from one event to another) then how can we say that time began at the moment of the big bang?
Because it's a component of spacetime. I think the idea is: no space, no time. But that is another notion that we, as creatures of this universe, find hard to accept.
 

Andy Kev.

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I'm sure AJB will correct this if it's too far off line, but the idea of the dot is that it is infinitely dense (sort of like oak but more so) and infinitely small which is obviously bonkers because if it has got the whole universe in it and as we can calculate the mass of the universe from observation, the dot is clearly finite. That perhaps speaks in favour of the multi-dot version i.e. lots of universes.
 
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J-G

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I can't see why that would be a problem if there was only the two of you
She was a Care Assistant in an old folks home so cakes were often provided by visitors to be shared out :(
 

bowmaster

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I'm sure AJB will correct this if it's too far off line, but the idea of the dot is that it is infinitely dense (sort of like oak but more so) and infinitely small which is obviously bonkers because if it has got the whole universe in it and we can calculate the mass of the universe from observation, the dot is clearly finite. That perhaps speaks in favour of the multi-dot version i.e. lots of universes.
This could be a long night........ if there was a multi-dot scenario then what do the scientists believe happened to the others - assuming only one (ours) made it to the big bang would they have been consumed after the event into our universe or would they have gone on to create parallel universes with their own attendant big bangs? I'm off to do some research - quite what this has all got to do with cutting the perfect dovetail I'm yet to discover....
 
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