Metric History

[smorgasbord]

A fun bit of history on the definition of a meter:https://www.nist.gov/si-redefinition/meter

 

[semenza]

Restarted this topic without the political content. Lets keep it that way.

  Thanks,

          Seth

 

[woodbutcherbower]

Sheesh. Why couldn’t they just use a tape measure?
[attachimg=1]

 

[Bob D.]

LOL, they couldn't round that up to 1,650,754 ?  [big grin]

 

[Cheese]

LOL, they couldn't round that up to 1,650,754 ?  [big grin]

Ya Bob they could...but then they'd be .27 wave lengths off and we now know what kind of serious issues that would present.  [smile]

 

[smorgasbord]

Sheesh. Why couldn’t they just use a tape measure?

I think it's interesting that the original definition was simply the length of a platinum bar kept in a climate-controlled basement in France. Problem was, anyone who wanted to ensure their meter bar/tape/whatever was correct had to go to great pains to get access to that hunk of platinum. And imagine trying to hold something up to that bar and dropping it or otherwise hitting it hard enough to change its length by even the slightest!

Then, in 1875, they made a new bar. This one had an "X" cross-section and instead of it being the exact length, it was longer but with two scribed marks to indicate the meter length, which had to be measured at the melting point of ice and standard atmospheric pressure. They also made 30 official copies that were distributed to enable companies to measure against them, somewhat more easily. The current standard is something that anyone with enough money can reproduce, so there's no dependence on a single source of truth anymore.

What cracks me up is that originally the meter was supposed to be 1/10,000,000 of the distance between the North Pole and the equator, but they screwed that up and so the real definition of a meter is actually 0.2mm shorter than it should have been. It's actually too bad that the meter wasn't defined as a whole number divided by the speed of light in a second. Then, for instance, the speed of light in a vacuum could simply be 300,000,000 meters per second.

 

[Gregor]

It's actually too bad that the meter wasn't defined as a whole number divided by the speed of light in a second. Then, for instance, the speed of light in a vacuum could simply be 300,000,000 meters per second.

That problem only occurs because a second is a crooked unit, stemming from the earth refusing to rotate around the sun each 100 self-rotations [wink]

 

[Crazyraceguy]

Well, that's just silly, almost as dumb as a foot being literally the King's foot. Then changing it when the king changed?
Of course, it was decades ago, but I thought I remembered something from school about the meter being based on something simple? This made it better, along with the simplicity of the base 10.

I wonder why the "foot" was divided into 12 segments? It could have been 10 and maybe some of this would never have happened.

 

[Michael Kellough]

“I wonder why the "foot" was divided into 12 segments?‘

12”=12 months? 1”=1 month?

At least they didn’t make a 1/4”=1 week  [tongue]

 

[Bob D.]

Well, that's just silly, almost as dumb as a foot being literally the King's foot. Then changing it when the king changed?
Of course, it was decades ago, but I thought I remembered something from school about the meter being based on something simple? This made it better, along with the simplicity of the base 10.

I wonder why the "foot" was divided into 12 segments? It could have been 10 and maybe some of this would never have happened.

Blame the Romans.
https://en.wikipedia.org/wiki/Inch

The inch (symbol: in or ″) is a unit of length in the British imperial and the United States customary systems of measurement. It is equal to 1/36 yard or 1/12 of a foot. Derived from the Roman uncia ("twelfth"), the word inch is also sometimes used to translate similar units in other measurement systems, usually understood as deriving from the width of the human thumb.

 

[smorgasbord]

I wonder why the "foot" was divided into 12 segments? It could have been 10 and maybe some of this would never have happened.

I think it's because fractions came first and so the number 12 could be divided in half, in thirds, and in fourths using "whole" numerators. The number 10 just goes in half, or fifths which is much less commonly needed and 12 gave us sixths anyway.

Decimals weren't in any real use until 1585 when Simon Stevin published a book. Heck, the US didn't adopt decimal currency until 1792.

 

[Crazyraceguy]

I wonder why the "foot" was divided into 12 segments? It could have been 10 and maybe some of this would never have happened.

I think it's because fractions came first and so the number 12 could be divided in half, in thirds, and in fourths using "whole" numerators. The number 10 just goes in half, or fifths which is much less commonly needed and 12 gave us sixths anyway.

Decimals weren't in any real use until 1585 when Simon Stevin published a book. Heck, the US didn't adopt decimal currency until 1792.

I have heard this before, but it sure seems more simplistic to deal with 10?

 

[guybo]

After reading all that I feel pretty much defeeted and in need of a pint [big grin]

 

[simnick]

I wonder why the "foot" was divided into 12 segments? It could have been 10 and maybe some of this would never have happened.

I think it's because fractions came first and so the number 12 could be divided in half, in thirds, and in fourths using "whole" numerators. The number 10 just goes in half, or fifths which is much less commonly needed and 12 gave us sixths anyway.

Decimals weren't in any real use until 1585 when Simon Stevin published a book. Heck, the US didn't adopt decimal currency until 1792.

I have heard this before, but it sure seems more simplistic to deal with 10?

Blame the Sumerians, it is why there are 12 hours on the clock as well:https://en.wikipedia.org/wiki/Sexagesimal

 

[Crazyraceguy]

After reading all that I feel pretty much defeeted and in need of a pint [big grin]

That's bad...  [eek]

 

[Crazyraceguy]

Blame the Sumerians, it is why there are 12 hours on the clock as well:https://en.wikipedia.org/wiki/Sexagesimal

Since you brought up time, have you heard or seen anything about the "new" calendar that has been proposed?
The idea IIRC, it that every month would be 30 days. Then the "extra" days, 4 or 5 depending on the leap year thing, would be a separate "week" would make it so that the first of the year would always be on the same day. It would also follow that every other date would be the same day of the week. It would never change. Some even suggest that this be "time off" for everyone.

 

[kevinculle]

LOL, they couldn't round that up to 1,650,754 ?  [big grin]

The 0.27 wavelength rounding might seem trivial, but recently an experiment confirmed Einstein's equivalence theorem (that acceleration and gravitation are equivalent) to an accuracy of 1 part in 10^14!  The rounding you suggested is about 17 million times larger than the precision of the Einstein experiment.  While units like meters, seconds and kilograms are necessarily arbitrary, the precision with which we establish them sets limits on the precision of experiments to understand how the Universe works.

 

[Euclid]

... It would also follow that every other date would be the same day of the week. It would never change...

And then a great many people (most I'd guess) would never get to have their birthday on a weekend, when they (and their friends) would be away from work without taking holiday leave... seems a touch harsh!

 

[squall_line]

... It would also follow that every other date would be the same day of the week. It would never change...

And then a great many people (most I'd guess) would never get to have their birthday on a weekend, when they (and their friends) would be away from work without taking holiday leave... seems a touch harsh!

Or never have a birthday, if they were born on the 31st...

Imagine always having St Patrick's Day on a... Wednesday?  Most of the world wouldn't care, but the alcohol lobby in America might have some words...

 

[Bob D.]

LOL, they couldn't round that up to 1,650,754 ?  [big grin]

Everyone takes my rounding comment above so seriously. did you notice the big grin on the end there?

It's a joke son; as Foghorn Leghorn would say.