Mixing Metric and Imperial units

[Araucaria]

This is from the Grauniad's report today of the Grayrigg train crash:

"You can only see 15ft [4.6m] in front of you," he told the inquest.

"Had I noticed the points out of synch, I could not stop the train. With

300 tonnes of metal at 95mph it is going to go wherever it wants. I had

no control.

"We stopped at 300m (984ft) that night because we were hitting stuff."

An

automatic braking system was triggered within seconds of the derailment

but even under normal conditions, a train at that speed would need half

a mile of track to stop.

Do we really need to be given those equivalents?

As the driver was speaking, rather than writing down his evidence, how does the reporter know he meant 300 (metric) tonnes rather than 300 imperial ones - a difference of about 5 tons (or 5 tonnes, you can take your pick)?  And did someone measure those 300 meters and make sure it really was 984 feet rather than an equally round 1000 feet? And what stopped the reporter from converting that "half a mile of track" into "[805m]"?

Mind you, this isn't the worst I've seen. Reports of ocean racing nowadays frequently have "tonnes" of water crashing into the cockpit of the yacht. If they had been "tons" instead it would, of course, have been 1.5% less water coming over the side. Far less frightening.

[Anton Redman]

I do not know. Went to price 20 cubic metres of storage in UK last week only to have to recalc in cubic feet for the benefit of somebody who was young enough to be my great grand son

[idun]

Unless you had pointed it out, I wouldn't have even noticed. I mix things all the time and they do in France a little too even though they don't think about it at all.

[Chancer]

I took great pleasure in telling a market trader that the livres of strawberries that he was selling should be 454 grammes not 500 and that for once he was selling his-self short not the customers.

I love throwing in the odd imperial unit to throw people off their guard, I was cutting some worktops for a pal today he had asked me to explain how the jig worked and why we had to deduct 136mm from the length that we required, simple said I the slot is central, the jig is 284mm wide you just have to subtract the width of the cutter, une demie pouce from 284mm and then divide by 2 and you get the 136mm [;-)]

[Gardian]

Frankly, I don't think that its that big a deal.

For us living out here, we're all quite accustomed to metric and almost certainly use it for everything. We think of food in its €'s / kilo and can decide whether its cheap or expensive. When we go back to the UK, we have to adjust back to sterling / imperial.

The UK is a bit of a mixed bag. Foodstuffs as above, metric for DIY measurements (because it's easier), miles for distances (because its ingrained), etc, etc.

I remember having a slightly drunk conversation with our Belgian neighbour who's a maths teacher. "This Imperial - its so illogical. 16ozs to a pound, 14lbs to a stone, 12 inches to a foot .......... " and so on. She got quite cross about it.

I just said to her that you can't change it and why should you? The British are quite relaxed about it and happy with the way it works for them. Come back in a hundred years time and maybe then. We then had another brandy.     

[idun]

A maths teacher would perhaps have had to work a bit harder if it wasn't all 'tens'.

 

It is logical. I think when I bake bread it is  beautifully illustrated, ONE  pint of water TWO pounds of flour and THREE spoons of salt. It is all tordue in metric. .568 water and .907kgs flour. It illustrates to me why our ancestors ALL used methods for measuring and weighing that were easy for everyone and not invented by scientists.

[Clarkkent]

[quote user="Gardian"]

Frankly, I don't think that its that big a deal.

[/quote]

I agree entirely. All food in the UK (with the exceptions of milk and ale) is sold in metric quantities. And frankly, it doesn't matter. I would guess that most people look at the size of the pack and determine their choice that way. Who cares how the weight is expressed if that's the size you want to buy.

I buy the fuel for my car in litres and express its consumption in miles per gallon (which is more intuitively acceptable than litres per 100 km, anyway.)

Those of us who went to school and learned Imperial measures are better at mental arithmetic than those who only know metric ... aren't we?  [Www]

[idun]

There is one thing that appears to be inevitableto me. When there is complete conversion, ie £SD to £p and FF to Euros prices increase....... a lot. I often wonder IF we still had gallons at the pumps whether they would have got away with the amount I am currently paying for a gallon of diesel and that is £6.26.

[Anton Redman]

For what it is worth the journalist was following the Guardian style guide

http://image.guardian.co.uk/sys-files/Guardian/documents/2004/07/15/styleguidepdfjuly2004.pdf

metric system

The Guardian uses the metric system for weights and measures; exceptions are the mile and the pint. Since understanding of the two systems is a matter of generations, conversions (in brackets) to imperial units should be provided wherever this seems useful, though usually one conversion — the first — will suffice. Imperial units in quoted matter should be retained, and converted to metric [in square brackets] if it doesn’t ruin the flow of the quote.

It is not necessary to convert moderate distances between metres and yards, which are close enough for rough and ready purposes (though it is preferable to use metres), or small domestic quantities: two litres of wine, a kilogram of sugar, a couple of pounds of apples, a few inches of string. Small units should be converted when precision is required: 44mm (1.7in) of rain fell in two hours. Tons and tonnes (metric) are also close enough for most purposes to do without conversion; again use tonnes.

Body weights and heights should always be converted in brackets: metres to feet and inches, kilograms to stones/pounds. Geographical heights and depths, of people, buildings, monuments, etc, should be converted, metres to feet. In square measurement, land is given in sq metres, hectares and sq km, with sq yards, acres or sq miles in brackets where there is space to provide a conversion. The floor areas of buildings are conventionally expressed in sq metres (or sq ft). Take great care in conversions of square and cubic measures

[PaulT]

[quote user="Araucaria"]This is from the Grauniad's report today of the Grayrigg train crash:

"You can only see 15ft [4.6m] in front of you," he told the inquest. "Had I noticed the points out of synch, I could not stop the train. With 300 tonnes of metal at 95mph it is going to go wherever it wants. I had no control.

"We stopped at 300m (984ft) that night because we were hitting stuff."

An automatic braking system was triggered within seconds of the derailment but even under normal conditions, a train at that speed would need half a mile of track to stop.

Do we really need to be given those equivalents?

As the driver was speaking, rather than writing down his evidence, how does the reporter know he meant 300 (metric) tonnes rather than 300 imperial ones - a difference of about 5 tons (or 5 tonnes, you can take your pick)?  And did someone measure those 300 meters and make sure it really was 984 feet rather than an equally round 1000 feet? And what stopped the reporter from converting that "half a mile of track" into "[805m]"?

Mind you, this isn't the worst I've seen. Reports of ocean racing nowadays frequently have "tonnes" of water crashing into the cockpit of the yacht. If they had been "tons" instead it would, of course, have been 1.5% less water coming over the side. Far less frightening.

[/quote]

and were they gas or electric meters [6]

[Araucaria]

Thanks for all the replies. I apologise for confusing PaulT - I picked what I think is an American site to do the conversions - http://www.asknumbers.com/MetersToYardsConversion.aspx - and perpetuated the American spelling (which my dictionary tells me was commonly the English spelling in the late 18th century).

My chief complaint about all this is what I think is called "spurious accuracy". No-one weighed the train afterwards to find its weight at the time of the crash. I doubt whether anyone measured those 300 metres either, so 1000 feet (or 300 yards) would have done just as well. Recipes very seldom need to be converted from ounces to a precise number of grams - in idun's example with a pint of water and two pounds of flour, it would probably work just as well with 600cc of water (instead of 568cc) and a kilogram of flour (instead of 0.907kg) - though the end result would be slightly larger.

And I don't see why "tonnes" should always be substitued for "tons" in modern writing, whatever the Guardian's style guide says, when it's impossible to tell the two words apart when they are spoken, and where the words are being used in circumstances where the difference in actual weight isn't important. For example, I got nearly 10 million Google hits for the words "tons of people" and only 400,000 for the metric equivalent. I was surprised it was even that many.

[Anton Redman]

For what it is worth I always prefix with Long Short or Metric.