Happy Metric Day!

[Technomancer]

For a fun time, ask 10 different american physists what a "meter" represents.

These days, the official definition is related to the speed of light.

[Eriana]

Awwww. T.T
I'm not very smart though so I guess that's why I don't get this. T.T

[Mithrandir]

I also learned that it can be related as such, though that's not the crux of my inquiry. I'm asking what it represents, which is a slightly different kind of worm-in-a-box.

[Eriana]

ahahaha...
I think I shouldn't bother being in this thread because I really don't understand a thing that is being said. Sorry everybody. ^^;;;

[Mithrandir]

So either way, measuring in feet and inches is easier to get a useful measurement

You measuring something people use individually or on a larger scale?

[TurkishMonky]

hmm... maybe i shoud return to cubits... those should be the easiest to measure with...

[Warrior4Christ]

I also learned that it can be related as such, though that's not the crux of my inquiry. I'm asking what it represents, which is a slightly different kind of worm-in-a-box.

Please do expand...

Oh, wait I think I see what you mean. Like a foot is the size of a foot... a metre is the length of.... a metre ruler?

And:
A metre is defined as the length of the path travelled by light in absolute vacuum during a time interval of 1/299,792,458 of a second.

See? It's not that hard to remember.

[Arnobius]

Please do expand...

Oh, wait I think I see what you mean. Like a foot is the size of a foot... a metre is the length of.... a metre ruler?

And:
A metre is defined as the length of the path travelled by light in absolute vacuum during a time interval of 1/299,792,458 of a second.

See? It's not that hard to remember.

Heh... yeah, like I said: arbitrary unit size selected with no bearing on common usage. (why 1/299,792,458 of a second exactly?) But don't get me wrong: If scientists want to standardize for exact precision, it's their business what units they want to use. I just get annoyed when they say "It's a disgrace that the US is one of a handful of nations that doesn't use metric..."

hmm... maybe i shoud return to cubits... those should be the easiest to measure with...

1 feet [international, U.S.] = 0.6773333 cubit [Egyption]
1 feet [international, U.S.] = 0.582235 cubit [Royal Egyptian]
1 feet [international, U.S.] = 0.6666667 cubit [English]
1 feet [international, U.S.] = 0.6864865 cubit [Roman]

Anybody know which one they used in the Bible?

Might have been easier if they chose one unit we commonly used as the base and made subunits and larger units in divisions/multiples of 10

[mitsuki lover]

Well considering how much time Israel spent in Egypt it might have been either the Egyptian or Royal Egyptian.Then again I am only guessing.

[blkmage]

The speed of light is 299792458 m/s.

And the US is not one of a handful of countries that haven't gone metric. It's one of three. The others are Liberia and Myanmar.

[Arnobius]

So three isn't a handfull? Must be a metric handful you're using

186,282.4 miles per second is another measurement for light speed (And a more practical one: Can you imagine calculating light speed in yards?).

Keeping in mind that the metric system was derived before the calculation of light speed, we can say that meters were used to calculate light speed, not that light speed was used to calculate meters. If scientists want to use that as an international standard, for the length of a meter it's fine with me. It's not the system I have an issue with, it's the attitude of people who think it's backward not to use it.

[Technomancer]

Well, like I said the original definition of the metre wasn't quite right so a new one had to be devised. As for Mithrandir's question, I'm not really sure what he's getting at by asking what it represents apparently as opposed to its defintion.

The point about metric though is that it is fundamentally simpler to use, and is absolutely required in any scientific or engineering work. Some of the basic quantities used don't even have a designation in the old Imperial system. Given that, and the fairly obvious need to trade with a world that is entirely metric, why bother with the trouble of learning two measurement systems?

[Mithrandir]

From what I recall of physics history (yeah, I had to learn it; no I can't tell you why), it started out much like technomancer said. They made a steel rod that was as close to that length as they could measure, and assigned that as the de facto standard. For a large portion of time SI still refered to the original hunk of metal in france as the actual measurement. It can be represented as a ration of that beam to the distance light travels, as previously mentioned.

At least, that's what I was taught. I honestly can't tell you if my teacher was smoking something, though.

[Arnobius]

That is what I recall. And the speed of light defining a meter was officially defined in 1983, and if people want to use it, fine.

But there is some real arrogance among some metric supporters, trying to say Americans are backwards savages for using it. Yes the ease of units of 10 is fine. But like I said, it is the size of the unit that is a problem. A gallon is often a more efficient size for dealing in liquids than a liter is (10 Gallons vs 38 liters). A foot is frequently a more convenient measurement than a centimeter when it comes to measuring distance or length. Buying meat by the pound is more useful than buying it by the killogram.

I suspect that if the metric system dealt in quantities people wanted to use, instead of some decimal conversion of an abstract distance, it would be easier to accept. But defining a meter by the speed of light or the difference between the equator and northpole that gives us a measure that's close to a yard. I think using the "Everyone else does it" argument isn't a good one.

[Mithrandir]

I think if you grew up knowing you were 180 CM tall, you'd think that was a much more usefull measurement than 5'11".

[Arnobius]

Well, since I guess we're just down to personal preferences, I'll just shut up and behave now.

[Mr. Rogers]

w0ot for the metric system! and for metric day! *delayed* XD

[Warrior4Christ]

10mm is a nicer number to use than say 7/16" (when dealing with spanners).

Although monitors and tyres are nice to measure in inches.

[Kaligraphic]

Actually, Mithrandir, though it changes nothing else, the original definitive bars were made of platinum (there were three originals), though a brass provisional bar was created prior to the marking of the definitive platinum bar.

Towards the end of the 1800s, after the Meter Convention (Treaty of the Meter) and the creation of the International Bureau of Weights and Measures (BIPM), a platinum iridium alloy was used to create the international standard prototype - which is still held by the BIPM in Sèvres, France, iirc - and copies were sent to the signatories of the convention.

Copies in iron were made of the original platinum bars for distribution, but steel has never been used for the definitive original or, afaik, for direct copies. (Iron experiences greater thermal expansion than platinum, and adding the iridium to platinum reduces thermal expansion even further. Steel typically undergoes even greater thermal expansion than iron, though the exact rate of expansion varies by the particulars of the alloy.)

In 1960, the meter was redefined in terms of a particular emission line of krypton (multiples of the particular wavelength emitted with a certain change of electron state, but I don't remember which one.)

In the early 1980s, it was redefined in terms of the speed of light.

Thank you all for reading this, it will be on the test.