Do Americans use metric system?

[pbehn]

The UK has experimented with metric politicians, the first version Ed Miliband wasn't great but better than Michael Foot, its early days.

 

[mikewint]

Was not referring to the actual metric measurement only that the prefix Latin MILLI- was in common language usage meaning 1000. A MILLION is called a million because it is one thousand 1,000s as a Millennium is 1000 years
The Latin Prefixes move the decimal point to the right making the measurement smaller by the prefix amount

 

[gumbyk]

Was not referring to the actual metric measurement only that the prefix Latin MILLI- was in common language usage meaning 1000. A MILLION is called a million because it is one thousand 1,000s as a Millennium is 1000 years
The Latin Prefixes move the decimal point to the right making the measurement smaller by the prefix amount

milli is one thousandth in decimal units, mille is the latin root that it comes from, and means one thousand, kilo is the decimal prefix for thousand. That's how some people find it confusing, there's six orders of magnitude difference between milli and mille.

 

[MiTasol]

Not to mention that it is all done exactly the way we count, by 10s and rather than having separate names for every unit that really tell you nothing about the measurement, like: TUN. What is it?, How big is it?, What does it measure?

Damn - forgot that one in post #122 when I covered the other tons

From memory it is a volume of wine but I cannot remember how much.

Checking on giggle it is
Definition of tun
1 : a large cask especially for wine
2: any of various units of liquid capacity especially one equal to 252 gallons
Synonyms for tun
Synonyms barrel, butt, cask, firkin, hogshead, keg, kilderkin, pipe, puncheon, rundlet (or runlet)
Examples of tun in a Sentence
in olden days an English ship's capacity was measured by the number of tuns of wine it could hold

I guess your question has opened a ton/tun of other contradictions in InFerial measurements and the question : is that 252 Imp or 252 US gallons.

 

[mikewint]

there's six orders of magnitude difference between milli and mille.

We're still talking at cross-purposes. Read carefully my post and the my previous posting.
When the historic Metric system was being developed it was decided to use BOTH Greek and Roman numbers as prefixes since, at the time, any educated person spoke one or both.
The Latin numbers Decem, Centum, and Milia for 10, 100, and 1000 were chosen to represent the smaller divisions of the base length measurement METER. So when the meter was broken up into TEN smaller pieces EACH smaller piece (of which there were TEN) was called a DECI-meter and each one was indeed 1/10 of the whole METER. In a similar manner EACH Decimeter piece was broken up into ten pieces making 10 x 10 = 100 total pieces. Since there are now ONE HUNDRED total pieces EACH piece was called a CENTI-meter and each one was, of course, 1/100 of the total meter. The last historic step was to break each centimeter piece into ten equal pieces giving 10 x 10 x10 = 1000 total pieces. As before since there are now ONE THOUSAND total pieces EACH pieces was called a MILLI-meter and each one was, of course, 1/1000 of the total meter

In the opposite direction the Greek numbers DEKA, EKATO, and CHILLOI were used to represent MULTIPLES of the base meter. The spellings have been Anglicized in the intervening years to our modern spellings DECA, HECTO, and KILO. So TEN meters laid end to end become a single DECA-meter and ten Dekameters laid end to end (making 100 total meters) becomes a single HECTO-meter and lastly 10 hectometers (making 1000 total meters) laid end to end become a single KILO-meter.

As science developed the need to measure things a LOT bigger than KILO and a LOT smaller than MILLI- soon became necessary. Steps of ten were insufficient thus below (smaller than) MILLI- the steps became THREE powers of TEN rather than ONE power
So a single MILLI-meter was broken up into 1000 equal pieces and each piece became, from the Greek word MIKROS (small), a single MICRO-meter. The abbreviation also required that the Greek letter MU ( μ ) be used since all English M (mega) and m (milli) were already in use. Exceptions were made because not all font sets had the Greek letter Mu in them thus MC is also an acceptable abbreviation. Medically you will often see mcg which is a MICRO-gram.
Each Micrometer is then broken up into 1000 equal pieces. Each piece becomes a NANO-meter from the Greek Nanus (dwarf)
Each Nanometer is then broken up into 1000 equal pieces. Each piece becomes a PICO-meter. Here the Metric Guys switched to the Spanish word PICO meaning BIT (also PEAK and weirdly BEAK as in PICO DE GALLO [Beak of Rooster]). Each of these pieces is then a PICO-meter.

Back to the top end, each one becoming 1000 times larger than the previous we have:
1000 Kilometers laid end to end becoming a single MEGA-meter from the Greek MEGAS (Great)
1000 Megameters laid end to end becoming a single GIGA-meter from the Greek GIGAS (Giant)
1000 Gigameters laid end to end becoming a single TERA-meter from the Greek TERAS (Monster)

 

[mikewint]

In the SI system it's not quite so easy for me to visualize some items, especially in terms of pressure, especially when you realize that a Newton is roughly the same weight as a typical apple. As such when you start talking about pressures of typical things like oil pressure, air pressure and steel or aluminum material properties you end up having to put those values in terms of kilo- or even Mega-Newtons/square meter (or kilo- and Mega-Pascals)

Here I would totally agree with you. SI has both improved the old Metric and in some cases made it more difficult in the man-sized world of measurement.
BUT, you needs must understand the WHY and Necessity of those changes.
The intent was a rational simplified system for all times and all peoples based on natural standards. The use of numeric prefixes attached to the base measurement so that anyone would know just by looking at the word for the measurement just how much and of what. If you belonged to the Correct Guild you knew exactly what a TOD was and what it measured.
[Do you know why Teachers used to ask students "Which weighs more a POUND of GOLD or a POUND of FEATHERS"] (It's feathers by quite a bit)
The original INTENT of the Metric system soon became lost as Science developed and more and more things besides length, volume, and mass needed to be measured. So units like FARAD, ERG, HENRY, DYNE, SIEMENS, STHENE, WEBER, BARYE, TESLA, PIEZE, MAXWELL, LUMEN, GAUSS, LUX, OERSTEN, STOKES, POISE, and ANGSTROM became metric units. So as earlier IF you belonged to the proper group you knew exactly what and how much.
Thus it was time to end the mess and clean house. In 1960 the SI system was adopted and SEVEN base units { second, metre, kilogram, ampere, kelvin, mole, candela } were accepted and defined. After that point anything else that needed to be measured would have to come from combinations of those base units.

So when we come to measure pressure which is FORCE per unit of AREA. We are forced to use just those seven base units. Thus FORCE becomes the NEWTON [One newton is the force needed to accelerate one kilogram of mass at the rate of one meter per second squared in the direction of the applied force or 1 kg⋅m⋅s−2] and area must be meters squared.
Thus PASCAL is then (in terms of base units ): One pascal is one kilogram per meter per second squared; that is, 1 Pa = 1 kg · m-1 · s-2. As you observed a very tiny amount of pressure, in US customary units 1.450 X 10^-4 PSI or 0.0001450 psi.
A better mental picture might be this: A newton of weight is about 1/4 Pound so imagine a Soda Cracker 3.25 feet by 3.25 feet. Spread evenly over the entire cracker 1/4 pound stick of butter. The butter exerts a pressure of ONE PASCAL on the cracker

 

[soulezoo]

This makes my head hurt...

 

[mikewint]

Its become even simpler and more universal now that there are no longer actual physical standards maintained.
In November 2018, the world's measurement experts voted and unanimously approved a revision of the SI that establishes a measurement system entirely based on physical constants of nature. The changes became effective on World Metrology Day, May 20, 2019.

Unit of length meter The meter, symbol m, is the SI unit of length. It 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 ΔνCs.

Unit of mass kilogram The kilogram, symbol kg, is the SI unit of mass. It is defined by taking the fixed numerical value of the Planck constant h to be 6.626 070 15 × 10-34 when expressed in the unit J s, which is equal to kg m2 s-1, where the meter and the second are defined in terms of c and ΔνCs.

Unit of time second The second, symbol s, is the SI unit of time. It is defined by taking the fixed numerical value of the cesium frequency ΔνCs, the unperturbed ground-state hyperfine transition frequency of the cesium 133 atom, to be 9 192 631 770 when expressed in the unit Hz, which is equal to s-1.

Unit of electric current ampere The ampere, symbol A, is the SI unit of electric current. It is defined by taking the fixed numerical value of the elementary charge e to be 1.602 176 634 x 10-19 when expressed in the unit C, which is equal to A s, where the second is defined in terms of ΔνCs.

Unit of thermodynamic temperature kelvin The kelvin, symbol K, is the SI unit of thermodynamic temperature. It is defined by taking the fixed numerical value of the Boltzmann constant k to be 1.380 649 x 10-23 when expressed in the unit J K-1, which is equal to kg m2 s-2 K-1, where the kilogram, meter and second are defined in terms of h, c and ΔνCs.

Unit of amount of substance mole The mole, symbol mol, is the SI unit of amount of substance. One mole contains exactly 6.022 140 76 x 1023 elementary entities. This number is the fixed numerical value of the Avogadro constant, NA, when expressed in the unit mol-1 and is called the Avogadro number. The amount of substance, symbol n, of a system is a measure of the number of specified elementary entities. An elementary entity may be an atom, a molecule, an ion, an electron, any other particle or specified group of particles.

Unit of luminous intensity candela The candela, symbol cd, is the SI unit of luminous intensity in a given direction. It is defined by taking the fixed numerical value of the luminous efficacy of monochromatic radiation of frequency 540 x 1012 Hz, Kcd, to be 683 when expressed in the unit lm W-1, which is equal to cd sr W-1, or cd sr kg-1 m-2 s3, where the kilogram, meter and second are defined in terms of h, c and ΔνCs.

 

[wuzak]

"Which weighs more a POUND of GOLD or a POUND of FEATHERS"] (It's feathers by quite a bit)

You may want to explain that one.

 

[wuzak]

Imperial units are now all defined in terms of metric units.

That is, the inch doe snot have its own standard measure, but is defined as 0.0254 metres. 1 pound is 0.453592 kilograms.

 

[XBe02Drvr]

In November 2018, the world's measurement experts voted and unanimously approved a revision of the SI that establishes a measurement system entirely based on physical constants of nature.

Hey, who's got my Tylenol?

 

[michael rauls]

You may want to explain that one.

I think he was trying to say they weigh the same regardless of which takes up more space but it does make for head scratcher of a sentence

 

[fubar57]

Copy/paste probably went haywire

 

[michael rauls]

Copy/paste probably went haywire

.........

 

[pbehn]

Gold used to be measured in Troy ounces and pounds.

Troy pound

The troy pound is 5 760 grains (≈ 373.24 g, 12 oz t), while an avoirdupois pound is approximately 21.53% heavier at 7 000 grains (≈ 453.59 g).

 

[Elmas]

Land Surveyors nowadays (well, my Father had his first centesimal theodolite early '60s...) divide a full circle not in 360° but in 400c, and 1c is divided in 100 parts (and not 60..) and so on. Much easier to use calculators when adding or subtracting angles.

The only people who use centimetres are dressmakers, everything else is millimetres / meters.
Never heard anyone else use cm...

It depends from the precision requested by the job.
For example a bricklayer here in Italy will use cm, even if cm it is not an SI unit, as the precision requested by his job is generally, at the best, +/- 0,5 cm (at the very best...), and he will laugh like mad if you will give him a drawing with dimensions indicated in mm, while if you indicate dimensions in meters you always will have that damned comma in the way. Bricklayers will always translate m in cm, and the possibility of an error arises.

In his memories Kelly Johnson laughing remembers of an episode when, early in his career, he was charged of the design of some masonry job, and with his astonishment found the bricklayers surrounded by a cloud of dust, as they were trying to achieve the precision indicated in the drawings that was that of an aeronautical standard.
American bricklayers were probably very polite, as here in Italy they should have greeted the designer with that in Italian is called a"pernacchia", behind his shoulders, of course.
To the contrary, a drawing addessed to a blacksmith must have dimensions indicated in mm, as the precision needed is +/ 0,5 mm otherwise bolts won't go though holes.

So, indicating in a drawing that a dimension is 3,23 m or 323 cm generally involves that a precision of +/- 0,5 cm is accepted, while if you indicate a dimension of 3230 mm the precision achieved in the finished product must be +/- 0,5 mm and an indication of 3230,0 mm so on...

The problem is that SI was imposed by Physics, with their Pascals and all that silly units, and not by Engineers. We were working so wonderfully with our own System (m and Kgf, as fundamental units).

 

[wuzak]

So it was a trick question?

 

[XBe02Drvr]

So it was a trick question?

....that backfired!

 

[mikewint]

So it was a trick question?

No not exactly a "trick" ,as such, but a way for teachers, at the time, to point out to students that the measurement POUND was of two types as Pbehn pointed out in his post above. The Troy (after Troyes, France a commercial trading center for precious things) System of weights and measures was much more strictly enforced and accurate than the English System. So valuable things and things that had to be accurately measured employed the TROY system. Remnants of the system are still in use today: CARETS for diamond weights; GRAINS for drugs and gun powder; and Ye Olde English DRAM shops.
Consider old British money. ONE POUND = 20 SHILLINGS and ONE SHILLING = 12 PENSE so there were 240 PENSE in ONE ENGLISH POUND
Now consider the TROY system. ONE TROY POUND = 12 TROY OUNCES and ONE TROY OUNCE = 20 PENNYWEIGHTS so that means that ONE TROY POUND = 240 PENNYWEIGHTS
As another aside take the measurement MILE, simple and easy right. Well again as with all things English not quite so JUST in the UK alone there were four different MILES in use and many more if you include the continent. Even today there are eight different MILES in usage

 

[gumbyk]

It depends from the precision requested by the job.
For example a bricklayer here in Italy will use cm, even if cm it is not an SI unit, as the precision requested by his job is generally, at the best, +/- 0,5 cm (at the very best...), and he will laugh like mad if you will give him a drawing with dimensions indicated in mm, while if you indicate dimensions in meters you always will have that damned comma in the way. Bricklayers will always translate m in cm, and the possibility of an error arises.

My bricklayer father never did...