Metric vs Imperial units

[strad]

with graphs,,,we need graphs

[Richard]

All timber sections are quoted in 'nominal' sizes - the actual size of sawn timber or the size of a machined timber section before any planing or moulding. The actual 'finished' sizes of machined timber will be 4-6mm less than those listed.

http://www.mertontimber.com/conversions ... icimperial

[Just_a_fan]

Back to topic.
When I go to study in England do I need to learn imperial units?
I am not very keen on calculating with hands and feed.

No, it'll be ok if you use metric. A foreign accent will be a help because any time you get it wrong, in a shop for example, they'll think "bloody foreigners" and help you.

Seriously, just about the only things that are imperial are drinks sold in pints (a good thing because a pint is bigger than 500ml ) and the speed limit / town distance signs (which are in miles). Everything else is dual-units or metric.

Although lots of people in the UK claim that the UK is imperial, in reality it is metric with a few 'traditional' units thrown in for fun.

[Jersey Tom]

Mep... if you're going into engineering or science for study, I think it would be worth your while to be familiar with dual units. Was required in many of my classes. I wasn't keen on using meters, kilograms, and pascals... but that's life.

And honestly... with the math and problem solving you'll be doing, unit conversions will be the least of your concerns and trivially easy by comparison to everything else.

[mep]

It’s a master course so I already know most of the metrical units.
The question is do I have to learn the imperial versions of them.
In my opinion it doesn't make sense to use imperial system for science. The metrical is simply better. Of course unit conversion is a minor problem but even in metrical world it takes some time to do it. Time you might not have in exams. You need a feeling for it and it’s good to build it up ahead.

Btw:. Race Car Vehicle Dynamics is written in imperial units.
Is it because it’s a quite old book?

No, it'll be ok if you use metric. A foreign accent will be a help because any time you get it wrong, in a shop for example, they'll think "bloody foreigners" and help you.

I don't care what they use in shops. I have been in countries where I could not even speak the language and still got my food.
I am not sure if it helps to have German accent in England?
Some might think "bloody Nazi".
Also on this forum I had to learn that Germans have no sense of humor.

[xpensive]

Way to go mep, don't bother with imperials at all, focus on understanding scientific relations, which is so much easier with SI only. You can always convert the end result to imperials if there's a need for ksi, BTU, gpm or Farenheit.

[Jersey Tom]

In my opinion it doesn't make sense to use imperial system for science. The metrical is simply better.

I've used both systems plenty, while in school and professionally. I don't agree that metric is better. It is no different. Either are trivially easy to use. After having metric extensively in years of physics classes, I still prefer imperial.

If you're already learning that Power = Torque * Angular Velocity, it's no more difficult to remember HP = Ft-Lbf * RPM / 5252. I'm sure just about every redneck, hillbilly gear head in the US can call that out from memory, so there's no excuse for professionals to not be able to handle it.

If you're already learning that 1 bar = 100 kPa, it's no more difficult to remember 1 atm = 14.7 psi, or 760 mmHg, or whatever. You have to remember Planck's constant for physics class being 6.626e-34 J, why is any other number challenging?

If I'm working on a car and know most of the suspension hardware is 6 & 8mm, that's no different than knowing that it's 1/4 and 5/16" (and need 7/16 and 1/2" wrenches)

Even C and F for temperature... if you know freezing is 0 and boiling is 100, why are 32 and 212 any damn different? A number is a number. There's nothing intuitive about boiling point being 100. Could be 1000. Could be 10. Could be 999. Doesn't matter!

Btw:. Race Car Vehicle Dynamics is written in imperial units.
Is it because it’s a quite old book?

No. Not that old, mid 90's. It is written in imperial units because it was put together by Americans. Those are the units we use. Still plenty widespread in pro motorsport here. Could we switch to Metric? Sure, we could. It would require changing over absolutely outrageous amounts of equipment and instrumentation, for really no gain. Just a different set of numbers to use.

In the real world when you're in industry and especially manufacturing and anything involving North America, chances are you're going to have to use Imperial and Metric units at some point in your career. Might as well learn it now and be done with it. It's not going away.

[Jersey Tom]

And honestly, the definition of a meter is no less silly than that of a foot, or that a foot is 12 inches. A human foot I can at least conceptualize in terms of scales of magnitude.

The definition of a meter used to be what... "one ten-millionth of the length of the meridian through Paris from pole to the equator." That doesn't exactly jump out at me for being easy to conceptualize.

Likewise with the current definition of "The meter is the length of the path traveled by light in vacuum during a time interval of 1/299 792 458 of a second."

Clearly that just jumps right out at ya

[Pup]

I believe the foot is 12" because it was originally a measure of the shoe and not the foot, as it would be a bit of a pain to take your shoes off every time you needed to measure something. And since it was likely standardized on the king's foot, that just made it doubly inconvenient. And while feet were smaller back then, along with everything else, shoes were generally bigger, since they were pointy. I made that up of course. Still, the primary reason that cathedral construction took so long back then - generations - is that every time you needed to measure something, you'd have to find a king and then convince him to take his shoes off, which they were invariably reluctant to do what with the open sewers and livestock on the streets and all.

My New Balance 9 1/2 MT100's, by the way, are precisely 12" stem to stern, which is less convenient than you'd think, since I only wear them when I run. If New Balance were to make a cathedral building shoe, I'd be set.

[Pup]

By the way, here's a link to a most excellent 40-page (US letter) history of lumber sizing in the US, for those who are interested.

http://www.fpl.fs.fed.us/documnts/misc/miscpub_6409.pdf

You can thank me later. For not copying and pasting the entire article here, that is.

[xpensive]

@JT;

Now that you've mentioned Planck's constant twice on this thread, could you please xplain what you use it for?

[marcush.]

It’s a master course so I already know most of the metrical units.
The question is do I have to learn the imperial versions of them.
In my opinion it doesn't make sense to use imperial system for science. The metrical is simply better. Of course unit conversion is a minor problem but even in metrical world it takes some time to do it. Time you might not have in exams. You need a feeling for it and it’s good to build it up ahead.

Btw:. Race Car Vehicle Dynamics is written in imperial units.
Is it because it’s a quite old book?

No, it'll be ok if you use metric. A foreign accent will be a help because any time you get it wrong, in a shop for example, they'll think "bloody foreigners" and help you.

I don't care what they use in shops. I have been in countries where I could not even speak the language and still got my food.
I am not sure if it helps to have German accent in England?
Some might think "bloody Nazi".
Also on this forum I had to learn that Germans have no sense of humor.

of course we don´t have any of that .one british team I had close relationships to called me Schulmeister ( I only learned later on that this indeed has war relation-rommel was nicknamed Schulmeister)...

I think you cannot afford to be ignorant and just ignore what is common practise in a team ..would you make the tyre guy learn psi and K just because you are more at ease with ? You will be quite lonely in the paddock in a short time then I`d guess... and K is of course only buying you a nod from the thermodynamic guys ...
so´my view is to listen to what is used in your environment and be sure to give information so everyone is understanding you ..plus be prepared to convert everything you hear to units you got a proper feel for plausibility..

[jon-mullen]

If you're already learning that Power = Torque * Angular Velocity, it's no more difficult to remember HP = Ft-Lbf * RPM / 5252. I'm sure just about every redneck, hillbilly gear head in the US can call that out from memory, so there's no excuse for professionals to not be able to handle it.

Of course you're right that it's easy, but it's still an extra conversion factor where SI derived units just get a name change. Either way is certainly "trivially easy" as you put it, but that doesn't stop people from making stupid mistakes, and they're more likely with our system. Actually the only thing that stops people from making stupid mistakes is knowing what's a reasonable magnitude for their answer to begin with, and that's why it would be convenient for us all to be on the same page, so we've all got an intimate feel for the same units.

If New Balance were to make a cathedral building shoe, I'd be set.

I bet they'd be the most comfortable cathedral-building shoe on the market, too.

[Richard]

mep - All education in the UK will be in metric. Forget imperial, until the day you get a job in the USA.

The only thing you will need to change is to use mm instead of cm, and a full stop ( . ) for a decimal place not a comma ( , ).

Oh, you'll need to learn to drink British beer, lots of it.

[Pup]

And he'll have to learn to drive on the wrong side of the road.