Whilst away on a short weekend break, I decided to buy a length of chain for my clutch handbag. As most of the contributors appear to be male, I should explain that a clutch handbag has no handles and is held all the time. This fashion was around in pre-mugging days. (The bag is french patent and is as sophisticated as it was when I bought for £3. 3. 0d. in Simpsons sale all those years ago). Anyhow enough nostalgia. I went to an ironmongers and we discussed the attachments we need to give the bag a strap. Then we came to the length. I was told the price per metre.
I measured the chain by draping it over my shoulder and finding the right length. The man produced a yard stick. The chain dangled below the 36" mark. He judged that bit to be about 3". I looked and agreed with him and I paid for a metre. A private contract reached to a successful conclusion by two satisfied parties. That's it. End of story.

We all see now that metric is much better for everyday use than imperial... ;-) Long live the metre !

Well done for totally missing the point!

Nice to see such consistency though, with a new year here and all that.

Some bloke is putting up a cat pen in my garden, BTW - not a metric measure in site - I can assure you!

This has nothing to do with consumer topics or clutch handbags but as everyone else gets off the suject, so shall I. Is that good grammer?) Whilst watching the Antiques Roadshow, the next generation, a boy of about eleven gave the length and width of a crocodile (dead)he had in Imperial.

"a boy of about eleven gave the length and width of a crocodile (dead)he had in Imperial. "

This is what the metrifascists hate the most.

Of course in their world this doesn't happen!

Reminded me of the BBC London news item that callenged the whole idea of this "young people use metric" thing:

Setting: Boys fishing
Lady interviewer: What's the larget fish you've caught
8 yr old boy: Oh, about 4 or 5 pounds
Lady Interviewer: Do you know what that is in kilos?
8yo: Nods (no)
Ldy Intv to other boy: Is it deep here?
other 8yo: Well I know that over there (points) its about 6 foot
Ldy Intvw: Do you know that in metric?
other 8yo: I dunno.

This was the scene after a lady from the UKMA announced that within 10 yrs everyone will know only metric!

BTW: The actual numbers I've used were re-guessed - I don't go around making notes about every minor detail!

Parental influence due to our partially converted system. The most annoying aspect of this whole debate.

It's also peer pressure, the playground community and the language of the street - it's called "community" or "society" (depending on which side of the fence you sit on). It's ageless, colour blind, and involves both sexes.

When the government steps in and controls our way of life and freedom of speech - THATS when we'll be taught a lesson on how to conform.
I'm sure MI6 (or is it MI5) have the technology to bug houses, playgrounds etc from a distance without the need for solid state microphones and the like. They could infiltrate these communities and sort things out from the inside - for good, that with subliminal hypnosis on TV and radio. Surely modern technology has the capability of breaking us and moulding us to a clone of the "perfect individual"? Then perhaps they can sort this mess out where we keep changing governments just because "people on the street" want to adjust who governs us. This "democracy" thing is such a "partial" thing - lets scrap it and conform to just one rule for all aspects of our lives.
Its so embarrassing that Britons can work in both metric and imperial - but how can we be made to "de-learn" without the use of neuro-surgery?

Yeah, I know I'm talking all "fantasy-like"

Just like if you heard someone say 10 years ago that it would be a criminal offense to sell a pound of bananas in 2003.

Ten years ago we knew that would be the case.

In 1996, the Labour Party (then in opposition) said that it opposed making the use of lb/oz a criminal offence.

Sorry, if -10 yrs ago- I said that a greengrocer would receive a criminal record for selling a pound of bananas I would be told that I was a rabid anti-european scaremongerer who takes the Sun very seriously on all issues "Europe".

Here's one to test the water - "it will be illegal for a manufacturer to put "inches" on one side of a ruler"

Ok, all we need to do now is wait 10 years!

[whistles]

[tapping foot]

[....]

Steveh: Here's one to test the water - "it will be illegal for a manufacturer to put "inches" on one side of a ruler"

Steveh, that's not a hard one is it ? Everybody knows that it will be like that.
Try to be more inventive, eg. within 25 years it will prohibited to sell beer by the pint; beer will be served in half litre or quarter of a litre glasses.

Conrad, so you honestly say that your fascist leanings make you presume that government will be involved in the production of rulers in the future?

Do you presume that in the future parents will get fines for teaching ordinary measures to their kids too?

If you had any influence you would truly be a dangerous man.

But you don't so I just laugh!

"Everybody knows that it will be like that".

Conrad - do you believe that 12-inch markings along a piece of wood will be unlawful in 2010? If so, do you think this is a good idea?

BWMA: "Do you believe that 12-inch markings along a piece of wood will be unlawful in 2010? If so, do you think this is a good idea?"

No, I don't think they will be unlawful. But I do think that they will mostly be replaced by 1-metre markings (or maybe 25-centimetre markings) since virtually all building plans will be done in metric by then.

at the risk of being a bore may I return to my clutch handbag and metre of chain measured with no more than a yardstick and a good eye, when I got home and remeasured I decided it really needed to be shortened by 3". Odd that it may seem to some contributors to this site, I use both metric and imperial. Sometimes, I use both when measuring an article for length and width. Recipes - I mix there. Methods of measurement are there for our convenience and pocket dictators in Parliament and Brussels should mind their own business.

I totally agree - if govt and brussels weren't involved I would be bothered getting involved myself.

I usually use millimetres for very small measures - it's convenient and I'm allowed to!

Traitor.

If you really think so.

Sorry to go on about this, but I have decided to shorten the chain even more. 21" this time. Perhaps someone might like to convert that into what-nots for Ralf. That way, he can be totally bored with my messages as the Imperialists.

I feel sorry for anyone who can't see the benefit of using a single coherent system of measurement for all purposes, especially one that is so well standardised and un-ambiguous as SI.

Vicki,

The trader you dealt with was pricing by the metre.
That means he should be measuring properly and selling by the same units. He shouldn't be guessing at anything.

Using a yard stick in those circumstances is irresponsible and potentially cheating on his customers.

How does using a yardstick constitute cheating?

"I feel sorry for anyone who can't see the benefit of usi.."

I actually feel sorry for you. Anyone who hates the word "yard", "inch" etc is surely batty. Furthermore you must have chronic blood pressure living in Britain with it all around you!

Please forgive my older brother "Metre Man" - he's been mixing with the "wrong sort" (our Mum's words) and he's got some dilusions of grandure (or however you spell it!).

He's taking special tablets though

"Furthermore you must have chronic blood pressure living in Britain with it all around you!"

Tell me about it!

I did say "potentialy" cheeting.

You cannot measure a metre accurately with a yard stick in the way this trader did.

Vicki didn't say whether the yard stick had cm calibrations as well as inch, but he did have to "guess" at the extra length, i.e. he didn't use cm markings on the stick to say measure the length in two 50 cm parts.

Vicki was happy with the transaction, fine. But practices like these are likely to produce errors. The errors may not be deliberate but the trader did not act responsibility and did not seem concerned about making sure of accuracy.

If he trades in metres he should equip himself with the right measuring equipment.

Ross: "Tell me about it!"

Do you honestly get flustered by words?

No, but everytime I hear such measurements I think of the failure of metrication.

Nicely put

<<
I feel sorry for anyone who can't see the benefit of using a single coherent system of measurement for all purposes, especially one that is so well standardised and un-ambiguous as SI.
>>

Then go ahead and use it. No one's stopping you.

I feel sorry for anyone who thinks that spending taxpayer money to convert a country to a new system of measurement and passing laws restricting their rights to choose what system they want to use is worth whatever benefit may be gained from having an "un-ambiguous" (what's the ambiguity in the English system) and "standardized" (how is the English system not standardized?) system.

By the way, I think you mean metric, not SI. SI, remember, does not include degrees celsius, liters, and many other measurements commonly used in "metric" countries.

"I feel sorry for anyone who thinks that...passing laws restricting their rights to choose what system they want to use is worth whatever benefit may be gained"

We have had such controls on the systems of measurement we may choose to use for centuries. There is nothing new here.

<<
By the way, I think you mean metric, not SI. SI, remember, does not include degrees celsius, liters, and many other measurements commonly used in "metric" countries
>>

While the litre is not strict SI, it is listed as one of the units that may be used indefinitely in conjunction with SI. (See pages 104/5 of the SI brochure - www.bipm.fr).

The degreee Celcius is defined by the BIPM as the offset from 273.15K. See page 96 of the same SI brochure.

have you changed your speedo dial to "m/s" yet?

Who cares whether litres, celcius, etc are not in conjuntion with the SI system. Weather forecasts all over the world for decades have given the temperatures in Celcius and is internationally recognised. I am unsure of the SI volume term. If it is cm^3 (same as a millilitre), then litres can easily be converted into these.

The SI units (e.g. metres per second, Kelvin, etc) are used in scientific formulae in maths, physics, chemistry, etc. I know this because I studied A-Level Chemistry and Maths at school. Does anyone know, is the kilojoule a unit of SI? Also, where does the calorie fit in? Is this metric or imperial?

The Joule is the SI unit of energy. kJ is an accepted and integral part of that.

The calorie or Calorie (kcal) is not part of SI.

And we tend to try to burn off our "calories" so we can lose a few inches and hopefully a stone or two.

I recommend "Atkins" by the way!

(how many people here actually know what "Atkins" is? - and no, it's not an old imperial measure!)

<<
And we tend to try to burn off our "calories" so we can lose a few inches and hopefully a stone or two.
>>

Calories are an old metric unit - one calorie beign defiend as the heat required ot raise the temperature of one gram of water by one degree Celcius.

It was phased out in favour of the Joule in (I think) 1960.

The calorie (as used in the food industry) was really 1 kilocalorie as defined above. A real mess if you do not know which sort of calories you are using.

SteveH wrote

<<
And we tend to try to burn off our "calories" so we can lose a few inches and hopefully a stone or two.
>>

When I was working in Germany, we had a real mix of nationalities. One of my British colleagues mentioned his weight in stones and a Spanish colleague asked "What sort of barbarian measurement is that?"

That particular spanish person was obviously a rude bigot and you distanced yourself from him, didn't you Martin?

<<
That particular spanish person was obviously a rude bigot and you distanced yourself from him, didn't you Martin?
>>

A "her" actually - I did keep my distance from her, she was a married woman.

Can you marry Oxon in Spain.

I thought it was outlawed!

If memory serves Atkins is the name of the author of a book about a popular but controversial method of losing weight.

The diet involves eating high protien fatty foods but no carbohydrates. Some theory about the body not storing the fat in the absence carbs.

It was featured on the recent BBC series about dieting.

and it came second place (draw second, both Atkins)
Third place was atkins also.

Yes it is a low carb diet which encourages ketosis (where the body releases ketones to unlock the sugar stored in our own fat) which literally burns stored fat for energy.

I lost almost two stone (almost 28lb, for the "cousins").

Atkins dies very recently after hitting his head, he was over 70 yrs old.

"Can you marry Oxon in Spain.

I thought it was outlawed!"

What?

"I lost almost two stone (almost 28lb, for the "cousins")."

What about the estranged relatives?

I'm surprised you didn't pick this one up:

"Atkins dies very recently after hitting his head, he was over 70 yrs old."

So to clear things up, this WASN'T a plan - I am not a murdered - I ACTUALLY meant "died".

And to the estranged relatives - I lost about thruppence ha'penny worth.

Erm,

Do they make "footbrake handbags" too?

I did notice it but decided not to pull you up!

<<If it is cm^3 (same as a millilitre), then litres can easily be converted into these.>>

Actually, the SI unit for volume is the cubic meter. Get that. It's a huge unit, but volume is length cubed, and the meter was a far too long choice for the length unit (probably because the French Revolutionaries wanted to make it as different from the foot as possible) so we're stuck with a big unit like m^3. Interesting how no one on this board, all measurement experts by now, knew that. Goes to show how often SI units are used.

By the way, the calorie is no where near phased out in science yet. It shows up in chemistry textbooks all the time. (It has, however, been phased out in physics.)

Whether people use calorie or kilojoule, it doesn't really matter. I still look at how many calories there are on food products. Actually, as an A-Level chemistry student a couple of years ago, despite having the name Calorimetry (probably never been changed), the enthalpy changes in reactions are now all done as kJ/mole.

<<
By the way, the calorie is no where near phased out in science yet. It shows up in chemistry textbooks all the time.
>>

American or British text books?

American and Canadian. My chemistry book even said something like "Even though the joule is the official unit of heat, the calorie is still leftover as the predominant unit used by scientists and engineers, so we will use it in this book." Note the distinction between heat and energy (the calorie was used for heat and the joule for energy before people figured out that heat and energy are the same)

Would someone care to tell me what CURRENT British chemistry texts use?

This is an extract from the Oxford Univeristy's Physical Chemistry web page:


<<
Energy

The Imperial unit of energy is the thermodynamic calorie, defined by:

1 cal = 4.184 J
1 Cal = 4184 J.

It is exactly this sort of lunacy that the modern SI system was designed to avoid.
For the small energies involved in individual atoms, the electron volt is a popular unit; in thermodynamic calculations, energies are often reported in kilojoules per mole:

1 eV = 1.60219 × 10-19 J
1 kJ mol-1 = 1.6605 × 10-21 J.

>>

This suggests that the Chemistry Dept at Oxford University uses joules, not calories or Calories.

This suggests that you took that from an opinionated source rather than an official one.

No professional source would refer to something as "lunacy" in context to some facts under which no opinion is required. Heck the literal word of "lunacy" doesn't even fit the context.

So I beg to differ.

I suppose it might be like the old metri-fascist lie that "British schools don't teach imperial", which I always find a source of amusement!

Steve, have a look at

<<
http://physchem.ox.ac.uk/~hill/tutorials/basics/nonSIunits.html
>>


This appears to me to be course notes that are handed out to students at Oxford Univeristy. They are not "official" in the sense that they ar eissued by a government, but one can usually regard univerisity lecturers as having some authority in teh subjects that they. The weight that one should put ontheor opinion depends on the person's status and also on the status of the university where they teach.

I do not know the lecturer concerned, but I believe that Oxford Univeristy has a reasonable reputation. On the basis of that I would put considerable wieght on the lecturer's opinion.

Already been there mate.

It also states that these measures are "in common use today"

Stop pointing that gun at your shoe!

<<
(the calorie was used for heat and the joule for energy before people figured out that heat and energy are the same)
>>

I'm no expert on the history of science but this doesn't sound very likely. I'd have thought that the link was fairly obvious given the effect of friction where mechanical energy is converted to heat energy. Joules into calories if you like.

The SI philosophy is to not proliferate different units for the same thing. The Joule serves the purpose better than the calorie because it is defined directly in terms of the metre, kilogram and second.

With that the thermal capacity of liquid water becomes 4.184 J/K (at around 277 K). Just another physical constant really which don't usually work out to easy numbers in any system. Nature isn't that kind to human scientists.

The figure should be 4.184 J K^-1 g^-1.

Do you go around fixing parking fines to car windows?

BOOOO!

Sounds like SteveH has been at the cider again.

<<
I'd have thought that the link was fairly obvious given the effect of friction where mechanical energy is converted to heat energy.
>>

Converting mechanical energy to heat energy has nothing to do with it. Just because you can convert one thing to another doesn't mean they use the same units. According to Einstein, you can convert mass to energy, but mass and energy have different units.

<<
Converting mechanical energy to heat energy has nothing to do with it. Just because you can convert one thing to another doesn't mean they use the same units. According to Einstein, you can convert mass to energy, but mass and energy have different units.
>>

Bud, the key question is to do a dimensional analysis of the unit used. Dimensionally, Mechanical; (ie potential and kinetic), thermal and chemical energy all have the same units namely M.L^2.T^-2 (M = Mass, L = length and T = time). For this reason they can (and in the eyes of engineers who use SI *should*) all have the same units of energy.

Although Einstein said that mass and energy are equivalent, they are dimensionally different as the famous equation E = mc^2.

If you are unconvinced by my argument, I am sure that MattS will back me up. (BTW I am usually pro-metric and MattS is anti-metric, but we are both engineers and both understand the concepts discussed above).

It's also worth noting that thermal energy and kinetic energy (energy of motion) are one and the same. Temeperature is really a measure of the kinetic energy of vibrating molecules.

Thats why the calorie and the joule relate to each other by a unitless constant.

I fully understand your argument. I am an engineering student too.
My point was that when the calorie was first used as a unit, scientists did not know that energy and heat were dimensionally equivalent. That is why the calorie was defined by heat flow into water (the heat needed to raise 1 g H20 from 14.5 to 15.5 C I believe) and the joule was defined by MKS units
(kg m^2 / s^2). When scientists determined that heat and energy/work were dimensionally equivalent, they had two units related by a dimensionless constant. The point is that they did not realize this till after the calorie was well established as a unit independently of the joule.

<<
I fully understand your argument. I am an engineering student too.
>>

You will then realise that a good deal of engineering is taken up with transfering energy of one type into energy of another type (eg converting chemical energy contained into coal into electricity or converting electrical energy into heat energy etc).

Since engineers are often concerned witht e economics of their machines, they need ot know the efficiency of these machines. Does it not make sense therefore to use the same units for energy so that the efficiency is the ratio of [usefuul] output energy to input energy?

Well, I'm a chemical engineer. I don't deal with electrical or mechanical energy. Most engineers only specialize in one area. And since the easiest way of measuring energy flow in chemsitry is by measuring the temperature change of a sample of water that absorbs the energy, calories provide the simplest calculations because the specific heat of water at room temperature is 1 cal/gK.

Anyway, in my original post I was only trying to explain how the calorie came about separately from the joule.

Bud,

Some chemical engineers do deal with electrical energy - especially if they use an electrical heater to heat the water! (A classic case of energy transfer).

"Bud, the key question is to do a dimensional analysis of the unit used. Dimensionally, Mechanical; (ie potential and kinetic), thermal and chemical energy all have the same units namely M.L^2.T^-2 (M = Mass, L = length and T = time). For this reason they can (and in the eyes of engineers who use SI *should*) all have the same units of energy."

Martin, I will back you up on the first argument. Just because two things are equivalent does not guarentee that they are dimensionally congruent, as in the case of mass and energy.

Now as to the argument about using the same unit for all energy, I do not agree.

I prefer specific kinds of units for specific applications. Just as in SI, no one would quote mechanical energy in Joules I would not quote mechanical energy in British Thermal Units.

For energy, I believe the following applies (correct me if I'm wrong).

Mechanical: Newton-meters and Foot-pounds
Thermal: Calories/Joules and British Thermal Units

While all the above units are dimensionally equivalent, you would use one and not the other depending on the application.

Thanks Matt.

I thinkt that you can also agree with

<<
(and in the eyes of engineers who use SI *should*)
>>

with the qualifier that you are an engineer who does not use SI.

Martin, you seem to have conversion-factor-ophobia. What's so hard about having different units for different types of energy, and converting whenever necessary. Like I said, sometimes calories are easier to measure, like when you measure the heat released in a reacion by the change in temperature of the surrounding water.

The ease of measuring in whatever units you find convenient for a particular situation far outweighs the nuisance of conversion factors, especially given the availability of calculators and computers.

Bud wrote

<<
Martin, you seem to have conversion-factor-ophobia
>>

I do computer contract work. One of my regular customers run a laboratory in the petroleum exploration industry and I often have to develope software that does various calculations. I usually check the formulae that I use form first principals to ensure that I am using the correct inputs. I find that using conversion factors an absolute pain.

May I give you an example of one of the most stupid measurements in the oil indsutry - quoting the amount of oil in an oilfield in barrels per acre-foot. In Europe, wells are drilled in metres and ground area is measured in hectares. We are stuck with barrels because that is what the wholesale markets used. If however we convert barrels per acre-foot to its equivalent SI form, we get a unitless fraction - we can say that the oilfield contains 5.6% oil (for example).

There is a basic SI formula to work out enthalpy change of a reaction involving water:

Q = M x C x T

Q = kJ
M = Mass (kg)
C = Specific Heat Capacity of Water (4.18)
T = Change in Temperature in Celcius/Kelvins

<<
I find that using conversion factors an absolute pain.
>>

I don't understant what is so painful in your oil example. Would you care to explain it to me?





By the way, here is another good example. The equation someone wrote above for heat flow has three terms multiplied together. If you use joules, you have to multiply three numbers. If you use calories, only two. The extra multiplication you MAY need later to convert to joules balances out this convenience.

Bud wrote

<<
If you use calories, only two.
>>

There is a third value - the constant.

Furthermore, if you are doing high precision work, you cannot assume that the specific heat of water is 1 cal.g^-1.C^-1. Here are a few values:

0 C - 1.0074
35 C - 0.9979
100 C - 1.0070

Above 100C, assuming that teh water is under pressure, the difference becomes larger.

<<When scientists determined that heat and energy/work were dimensionally equivalent, they had two units related by a dimensionless constant. The point is that they did not realize this till after the calorie was well established as a unit independently of the joule.
>>

Uh, Bud, that was done in 1847, by Joule himself. Perhaps it is not too soon to incorporate his result into the body of engineering knowledge.

What's all this 'reviving ancient threads' malarky?

And where is Bryan?

Hasn't anyone told him about "erin" yet?