Practical aspects of Metric -v- Imperial measurement systems

[spacesailor]

The metre is based on an " atomic number " of some sort.

The french drive on the Wrong side of the road, after the french king had a big argument with the English crown, and made the rule.

No other country had rules of the road..

The Last country was New Caladonia, were the " next car coming around the corner, Sets the rule " Now they all drive on the French side of the road.

spacesailor

 

 

 

 

 

 

[willedoo]

 

45 minutes ago, spacesailor said:

The french drive on the Wrong side of the road, after the french king had a big argument with the English crown, and made the rule.

Wasn't it originally to do with horses. The near side of a horse is it's left side and people on foot leading horse drawn vehicles would be on the left side of the horse. If traffic stuck to the right hand lane, the opposing drivers would pass beside each other like our modern day car drivers. Or is that just an urban myth?

[old man emu]

The official definition of the length of a metre is: “The metre is the length of the path travelled by light in a vacuum during a time interval of 1/299 792 458 of a second.”

[Yenn]

What was the original definition of a metre? When the metre came into use we could not determine how far light travelled.

[octave]

The original definition was  one ten millionth the distance from the equator to the pole. Later on in the 1800s an "International prototype metre bar was created.  Back in history + measurement systems related to natural things such as your foot or a barleycorn, this was good enough for the times but as we have become more scientifically and industrially advanced we need higher  level of accuracy. It does make sense to use physical laws to define measurements.  Of course most of us do not need to measure the the distance light travels in order to know what a metre.   

[spacesailor]

ALL the horses in England are led by the halter being on the nearside, the Footpath.

Horses pulling barges, walk on the left of the canal.

Men walk on the outside ( the right ) of women to leave their Right sword hand free.

spacesailor

[old man emu]

 A new unit of length, the metre was introduced – defined as one ten-millionth of the shortest distance from the North Pole to the equator passing through Paris, assuming an Earth's flattening of 1/334.

 

The French Geodesic Mission  was an 18th-century expedition to what is now Ecuador carried out for the purpose of measuring the roundness of the Earth and measuring the length of a degree of latitude at the Equator. The equatorial mission was led by French astronomers Charles Marie de La Condamine, Pierre Bouguer, Louis Godin and Spanish geographers Jorge Juan and Antonio de Ulloa. Bouguer, La Condamine, Godin and their colleagues measured arcs of the Earth's curvature on the Equator from the plains near Quito to the southern city of Cuenca. These measurements enabled the first accurate determination of the shape of the Earth.

 

The French Academy of Sciences had commissioned an expedition led by Jean Baptiste Joseph Delambre and Pierre Méchain, lasting from 1792 to 1799, which attempted to accurately measure the distance between a belfry in Dunkerque and Montjuïc castle in Barcelona at the longitude of Paris Panthéon. This portion of the Paris meridian was to serve as the basis for the length of the half meridian connecting the North Pole with the Equator.

 

When an International Commission for Weights and Measures was convened in Paris to settle the true length of the metre, it adopted on 22 June 1799 a standard metre based on the length of the half meridian connecting the North pole with the Equator. The metre was defined as the ten-millionth of the half meridian's length extrapolated from an Earth's flattening of 1/334 obtained from the results of the survey by Delambre and Méchain combined with those of the Peru meridian arc as established by La Condamine and his colleagues.

 

he metre is defined by taking the fixed numerical value of the speed of light in vacuum, 𝒸, to be 299 792 458 when expressed in the unit m s−1, where the second is defined in terms of the caesium frequency ∆ν. The second is defined by taking the fixed numerical value of the caesium frequency ∆ν, the unperturbed ground-state hyperfine transition frequency of the caesium 133 atom, to be 9 192 631 770 when expressed in the unit Hz, which is equal to s−1.

[onetrack]

Quote

I like to be bi-mensural.

I trust you're not ambidextrous, too. To be both, would be a real burden to carry.

[spacesailor]

SEE !.

All scientific mumbojumbo, BY French scientists

SO

Half the Meriden to the Equator ? .

A quarter of the Earth,  throw in some south American measurements for good luck.

All by the French ?,. After flattening the poor sucker Earth by 1/334 ?.

MAKES SENCE to the French.

spacesailor

[octave]

Its main advantage units relate to each other.   A litre of water weighs 1kg and its volume is a cubic decimeter or 10cm x10 cm or  100mm x100mm. What does a gallon weigh? 8.33 pounds, not so easy to remember or do calculations  with.   There are two obvious temperatures that relate to our every day life freezing point 0 degrees Celsius and boiling point 100 degrees Celsius or in imperial  freezing point 32 degrees  and boiling point 212 degrees .  The metric measurements I have quoted are from memory because they are very easy to remember. I had to look up the imperial measurements.   

 

Again I have absolutely no problem with what individuals use to measure a piece of wood, doesn't matter to me at all but as a nation that strives to participate in science engineering an technology with the rest of the world we must use the same terminology.  

 

In 20 years time this will not be an issue.  I don't suppose there would be many people around now still complaining about decimal money.

 

 

[onetrack]

I reckon the simple reason why so many Americans have a hatred of the metric system, is because they believe the French invented it, and control it.

 

You've never seen hatred of anything French, on a major level, until you start talking to the average backwoods American.

 

They still reckon they saved the ar$e of the French in both WW1 and WW11, and they still reckon the French are worse surrender artists than the Italians.

 

The truth is the French were as good at fighting as anyone else, but their leadership and Govts were pathetic. They had a lot of good equipment, too - but the Germans always had more, and always used surprise as their favourite war method.

 

The Americans will never admit to the fact that they had no American tanks of any kind in WW1 - and they took Renault tanks back to the U.S., and copied them!

 

Edited January 30, 2021 by onetrack

[nomadpete]

Onetrak, I think that sentiment goes both ways.

A long time ago when colour tv came to the world there were three main technical methods of adding colour to TV pictures.

The US had NTSC method which we Aussies called 'Never The Same Colour'. The Brits solved the US poor colour rendition by their own method (PAL). The French looked at these and of course they came up with their own unique system which was called SECAM. I can't recall the French for this acronym but we Aussies called it 'Something Essentially Contrary to Anything American'. Every aspect of the signal was totally opposite to the US standard AND the British standard.

In truth a major driver of each system was the protection of each country's own manufacturing industry because a TV purchased in USA or England wouldn't work in France!

 

Finally though, the PAL (which Australia adopted) produced the best colour rendition, but we stopped making stuff here, didn't we!

 

Edited January 30, 2021 by nomadpete
Added words lost in space

[old man emu]

 

2 hours ago, onetrack said:

I trust you're not ambidextrous, too. To be both, would be a real burden to carry.

Well, on the one hand it would, but on the other hand ....

 

[old man emu]

1 hour ago, octave said:

I don't suppose there would be many people around now still complaining about decimal money.

Decimal money is easy for calculations with a computer, but a bugger when you have to do mental calculations. For example, 6 bread rolls cost $2.75. How much is one roll, and can you pay for it with coins?

 

There were 240 pennies to a pound because originally 240 silver penny coins weighed 1 pound (1lb). The English penny, originally a coin of 1.3 to 1.5 grams (0.042 to 0.048 troy ounces; 0.046 to 0.053 ounces) pure silver, was introduced c. 785 by King Offa of Mercia. These coins were similar in size and weight to the continental deniers of the period and to the Anglo-Saxon sceats which had preceded it. Pennies of the same nominal value, one 240th of a pound sterling, were in circulation continuously until the creation of the Kingdom of Great Britain in 1707.

 

240 is a good number because it has a lot of factors:  1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 20, 24, 30, 40, 48, 60, 80, 120, 240.. However 10 is a bad number because it only has a few factors 1,2,4,5,10,20,25,50 and 100. When a number has a lot of factors it can be divided into many smaller parts, which makes pricing small amounts of goods easy. 

 

Decimal currency suits computerised calculations, and since we are moving inexorably to cashless transactions, and a lot of day-to-day goods are sold in metric units, it is unlikely that 240 will ever return to our lives as a currency unit.

[nomadpete]

So, in my head, I'd have trouble working out the price of one bread roll when a pack of six cost £1 three and ninepence!

 

I can't even recall how to write it let along calculate it!

 

In your example I'd approximate in my head . One roll is between 40c  and 50c

Edited January 30, 2021 by nomadpete

[old man emu]

I wasn't talking about going back to pounds, shillings and pence when I wrote $2.75. I was using normal Australian pricing that I would see on a packet of rolls at Woolies. At that price, each roll is 45.83 cents. Woolies would not dare lose 0.83 cents per roll by selling them at 45 cents. There are no one and two cent coins, so I can't pay 46 cents and get four cents' change. So I have to pay at least 50 cents per roll. It costs me more per unit to buy less. Woolies is happy.

 

I churned over this application of decimal currency to the purchase of day-to-day food items and realised that it is only baked goods like bread rolls, and canned drinks that can be bought singly. Fruit, vegetables and meat are sold by weight. Everything else is packaged. So as well as paying for the edible stuff, I have to pay for the manufacture of the packaging.

 

[Old Koreelah]

20 hours ago, Yenn said:

What was the original definition of a metre? When the metre came into use we could not determine how far light travelled.

Originally defined as one ten millionth the distance between the North Pole thrust France to the Equator. That means 10,000km.

 

Everything else in the metric system is derived from this measurement: volume, mass, energy... 

As better technology allowed more accurate measurements of the earth, they needed a better standard and based the meter on the wavelength of Krypton.

 

My favourite conundrum: the ancients divided the circular earth into 360 degrees; the French said the equator was 40,000km round. 

 

Divide 40,000 by 360 and you get 111.1111111111111111111

 

 

 

 

 

 

 

 

[Old Koreelah]

17 hours ago, onetrack said:

...The Americans will never admit to the fact that they had no American tanks of any kind in WW1 - and they took Renault tanks back to the U.S., and copied them!

 

American aeroplanes were backward as well; development of aviation had been handicapped by the patent wars fought by the Wright brothers.

The Americans enthusiastically adopted French planes.

[Yenn]

Thinking back to my school days when we did exercises like 4 rolls cost six pence three farthings, how much change would I have from a florin if I bought  six rolls? Answer 13.875 pence, done easily on my calculator, but I am too lazy to do it in my head.

Even when Britain went metric money wise they were still teaching Imperial money in Hong Kong, even though Hong Kong had decimal coinage. Of course that was when Hong Kong was ruled by Britain and Hong Kongese did not have democracy.

[old man emu]

On 31/01/2021 at 2:00 PM, Yenn said:

4 rolls cost six pence three farthings, how much change would I have from a florin if I bought  six rolls? Answer 13.875 pence, done easily on my calculator,

4 rolls = 6 +3/4 pence

6 + 3/4 pence = 27/4 pence

1 roll = 27/4 x 1/4 = 27/16

6 rolls = 27/16 x 6 = 10 + 1/4, ten pence farthing.

 

Or 6 rolls = 4 x 1.5

6 rolls = 27/4 x 1.5

= 6.75 x 1.5 = 10 + 1/4.

 

You would have known that you were wrong with 13.875 simply on estimation since 13 pence is more than twice 6 sixpence ha'penny.

[old man emu]

Getting back to the use of Imperial measurements for small lengths, I found this description when I was looking for come coping blades at Bunnings.

[onetrack]

Well, they still use TPI for thread measure, so why not chuck in the other inch dimensions as well! 

[Old Koreelah]

Have a closer look at their stock; you might notice a significant increase in American measurements. Some items have no metric measurements, clearly against our laws.

[old man emu]

I think that for things like tools, or replacement blades like the example I gave, the article is being sold as a completed thing. They are not being cut from a roll of blade material for each sale, as electrical cable is. So for these things, the published dimensions are simply a guide to sizing. For example, I need a bandsaw blade that is 1085 mm long, but there are other longer sizes available. I wouldn't go to a saw shop and buy the blade by length, then fasten the ends together to make the band.

[onetrack]

You can do that if you have a quality brand of bandsaw, which has it's own built-in blade butt-welder.

You buy the saw blade in a roll, and cut off the exact length you need, and then butt-weld it with the saws butt-welder.

 

Here's one on eBay. The butt-welder is shown in the 3rd photo.

 

https://www.ebay.com.au/itm/124031475994?chn=ps&norover=1&mkevt=1&mkrid=705-139619-5960-0&mkcid=2&itemid=124031475994