Metric System Rewrite

[Superfluous J]

What's about that XKCD picture, where they say 2 L = 3 liter botte. Is liter an american unit equal to 1.5L? (Never heard of that one)

It's tradition to post the picture you're talking about when talking about a picture. I browsed through the thread and didn't see any XKCD pictures posted.

A 2 liter soda bottle in America contains 2 Liters of Soda and weighs* about 2 kilograms. SOURCE: I live here.

*I know Kilogram is not a unit of weight. You know what I mean

[dharak1]

http://xkcd.com/526/ This is the XKCD he is referencing. I am also pretty confused about why it says 3L = 2 liter bottle.

[Nibb31]

http://xkcd.com/526/ This is the XKCD he is referencing. I am also pretty confused about why it says 3L = 2 liter bottle.

Probably a typo. Nobody's perfect.

[Kulebron]

Ok, now that's clear, thanks!

[Camacha]

I would propose some additional changes. Pretty much all suggestions are made to eliminate weird things that crept in over time, or to eleminate arbitrary elements that were never fixed by introducing the metric system.

- Make sure that 1 kg matches exactly/as exactly possible again with 10x10x10 cm of water at its densest (and not very close, as it is now). Picking water is arbitrary, but it is a intuitive and common substance and fits nicely with the celcius/kelvin scale.

- Fix time to a non-arbitrary (or less arbitrary) scale and system, so that you can calculate time as easily as numbers. It should be manageable in daily life, yet be as clear as decimal

- Possibly do the same with degrees (as in a circle, grad/gons do not seem appropiate enough), preferably something that matches with the new timekeeping as clocks tend to be mostly analog style.

- Use a universal meaning for the comma and period, instead of 985.832 and 985,832 switching meaning depending on what part of the world you are in.

- Make grams the base unit, either by calling what is now a kilogram a gram, or simply by changing what the official base unit is.

[ZetaX]

Using water is bad for several reasons. What does "at its densest" mean¿ You would need to at least add the amounts of the isotopes of hydrogen and oxygen in your water, and the pressure the water is under (water is not truly incompressible).

The fact that 60 and 24 were also chosen due to being divisble by small numbers is also not to be neglected. Actually, the number 10 is rather randomly chosen from the amount of fingers we have. E.g. base 30 would continue most of the current ones, but you still have somehow to consider that time measures days, but also years, and those two are pretty much incommensurable.

[Superfluous J]

Using water is bad for several reasons. What does "at its densest" mean¿ You would need to at least add the amounts of the isotopes of hydrogen and oxygen in your water, and the pressure the water is under (water is not truly incompressible).

The fact that 60 and 24 were also chosen due to being divisble by small numbers is also not to be neglected. Actually, the number 10 is rather randomly chosen from the amount of fingers we have. E.g. base 30 would continue most of the current ones, but you still have somehow to consider that time measures days, but also years, and those two are pretty much incommensurable.

I wish we used base 8 (who counts on thumbs anyway?). Would have solved a bunch of problems. Some caveman out there is kicking himself over missing out on that one.

Water has the benefit of being universally available. I don't see any reason why the official definition can't state pure H20 (with an isotope spread that matches reality) at a specific pressure and temperature, say 300 kelvin and 100 kilopascals. That would allow school children to still get pretty darn close at room temperature at sea level with tap water.

[Kryten]

I don't see any reason why the official definition can't state pure H20 (with an isotope spread that matches reality) at a specific pressure and temperature, say 300 kelvin and 100 kilopascals.

There's no single isotope ratio that 'matches reality'; they vary in samples from different environments.

[Camacha]

Using water is bad for several reasons. What does "at its densest" mean¿

Simply what it tended to mean: around 4 degrees. After that ice starts forming, causing an increase in volume. The other issues you bring up are valid, but there is no reason that with modern technology and knowledge a solid definition could not be developed that is universally true without resorting to a physical object to indicate what you mean. There is no need for it to even actually exist, as long as you can realistically relate to it in some way.

The fact that 60 and 24 were also chosen due to being divisble by small numbers is also not to be neglected. Actually, the number 10 is rather randomly chosen from the amount of fingers we have.

True, but we are working with it and pretty decently too. Switching to another system is an option too, as long as it is uniform across all units - though I can not see that ever being accepted without a total collapse of civilization. Time sort of works the way we do it now, but is a bit of a disaster when adding or subtracting and with added complexities like leap seconds and days.

[Camacha]

There's no single isotope ratio that 'matches reality'; they vary in samples from different environments.

So there is an isotope ratio that matches reality, only in a specific case. It does not matter though.

[Vaebn]

The great power of the metric system is not the actual length of the first few base units, is the relationship of the units with all the rest. This then allows for easy multiplications and mathematically meaningful/easy to deal with orders of magnitude and stuff.

If a change was to happen, I'd say these:

What you actually pick your base unit to be is utterly irrelevant (always) and it would be particularly so in a universe which is "infininetly big" and "infinitely small". However, interestingly, our universe does not appears to be so, there does seem to be point where reality's meaningful "detail" stops, and that's the planck lenght.

Because we build our system from the meter downwards the current lenght of the planck lenght is defined as 1.616199(26) × 10^-35 metres.

This appears to be a bit of an ugly number for a thing (potentially) so meaningfully fundamental. A feel good change then for a sexy species caring for this sort of thing, would be to define the planck lenght as the fundamental unit "1".

This doesn't go just for length. In a similar fashion, the smallest unit of time can too be defined in term's of a planck length (planck time), it's current value being 5.39106(32) × 10^-44 s. Again I think there would be some elegance in calling "it", unit "1".

Everything then would be redefined in terms of multiples of it. Although even "Terraplancks" and "Pettaplancks" don't approach usable lengths for daily usage. So... yeah. I hope you like superscripts on all your daily units.

Edited January 4, 2014 by Vaebn

[Superfluous J]

Although even "Terraplancks" and "Pettaplancks" don't approach usable lengths for daily usage. So... yeah. I hope you like superscripts on all your daily units.

Love the idea, and that's not a big deal. While technically the units we use would look horrible, we just define the base unit of length, say the Plength, as whatever multiple of the Planck Length is close to a Meter (or a foot. Meter's always felt a bit too big to me) and the base unit of time, say the Tanck as the multiple closest to the second or minute (or even hour).

Then we can talk about kiloplenths, or milltancks.

Bonus: Millitancks is a cool name.

[Palladium Corp]

Kelvin is defined by the SI system as the fraction 1/273.16 of the thermodynamic temperature of the triple point of pure water under 1 atmosphere of pressure. This makes absolute zero 0K, or -273.15 C, and the melting point of pure water 273.15K, or 0 C. This makes the Celsius scale equivalent to Kelvin+273.15.

The second is based on the radiation emission cycle of Rubidium, the metre is based on the value of C in a vacuum, and the second.

Only the Kilogram is not based upon fundamental constants. The next meeting of the General Conference of Weights and Measures is this year, so hopefully they will re-define the Kg in terms of Plank's constant (h).

[magnemoe]

I propose the following changes to the metric system:

-Replace all dates and times with seconds since the epoch, which is the moment at which these changes are effected

-If the meter is so long as to make the metric system impractical, then so shorten it as to make it practical.

Any ideas, comments, criticisms?

-Duxwing

Computers use an second count as internal measurements. this is totally unpractical impractical for everyday use time time is 25,642,365 is just confusing.

Just using it within one day will get you 86400 at 24:00.

I would divide the day into 1000 minutes as base units down from 1440, rest is decimals 0.01 is pretty close to an second so we call it so.

For more accuracy you use an 10^6 unit day or 0.1 second.

Days stay as they do for obvious reasons.

Weeks is an issue about work days, nothing else: 10 days with three off might be better?

Months, I would have 12 months of 30 days, 5-6 odd days between Christmas and new year as no work is done anyway.

Meter is an suitable length, humans is between 1 and 2 meter long meter is still long enough to work well for measuring houses.

[Vaebn]

Kelvin is defined by the SI system as the fraction 1/273.16 of the thermodynamic temperature of the triple point of pure water under 1 atmosphere of pressure. This makes absolute zero 0K, or -273.15 C, and the melting point of pure water 273.15K, or 0 C. This makes the Celsius scale equivalent to Kelvin+273.15.

The second is based on the radiation emission cycle of Rubidium, the metre is based on the value of C in a vacuum, and the second.

Only the Kilogram is not based upon fundamental constants. The next meeting of the General Conference of Weights and Measures is this year, so hopefully they will re-define the Kg in terms of Plank's constant (h).

Well even those are quite a bit arbitrary. Triple point of water under 1 atmosphere? Whose atmosphere? This is something humans might feel good about, but would be completely meaningless to an alien civilization. For that matter not even Earth has 1 atmosphere of pressure all over the place.

Second has been retconed to match Rubidium. But of course selecting "Rubidium" specifically out of all isotopes was an arbitrary decision because it was conveniently close to the previous arbitrary lenght of the second, which happened to be the 60th division of the arbitrary minute length, which in turn was the 60th division of the arbitrary hour lenght, which in turn was the 24th, of the arbitrary but I supposed pretty meaningful, "day" period. Which is based on Earth's locally significant, but universally insignificant spinning speed.

Planck units on the other hand, ought to be immediately understandable even to an alien civilization assuming our physics are finally anywhere near to reality. "

"Which is your base unit of lenght?", "The smallest possible one", "Oh that one". "Which is your base unit of time?", "The smallest possible one", "Of that one". etc

Equations become sexy too. The speed of light for example is C = 1

Edited January 7, 2014 by Vaebn

[andrewas]

Well even those are quite a bit arbitrary. Triple point of water under 1 atmosphere? Whose atmosphere? This is something humans might feel good about, but would be completely meaningless to an alien civilization. For that matter not even Earth has 1 atmosphere of pressure all over the place.

Not a problem - the gas/liquid/solid triple point of water occurs at 273.16K and 61173Pa. Any aliens, using pure water, will find the exact same triple point. You can't have any other temperature or pressure in a triple point cell, or you'll have only two of the three phases in it.

[Vaebn]

Hm, correct. I hadn't realized the full implications of its triple pointness.

I still prefer planck units though, just due to what they do to so many of the constants and equations

E = MC^2 -> E = M! How cool is that?

Edited January 7, 2014 by Vaebn

[Palladium Corp]

Oops, sorry. I was remembering wrong. The second is actually defined by "9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom". Not rubidium at all.

I also realise in hindsight that including "1 atmosphere" was unnecessary. Sorry for any confusion caused.

[Vaebn]

*Stands on his rhetoric pedestral*

See? See the folly of the SI-ists! Confused about their own unit definitions!

Planck units I say! Planck units! Driving our cars around and talking about their speed directly in terms of "nano-c" is what Einstein would have wanted.

Edited January 10, 2014 by Vaebn

[Ralathon]

*Stands on his rhetoric pedestral*

See? See the folly of the SI-ists! Confused about their own unit definitions!

Planck units I say! Planck units! Driving our cars around and talking about their speed directly in terms of "nano-c" is what Einstein would have wanted.

Sure, I'll go to the shop and grab myself 5e7 M_P of sugar! Planck units are awesome when doing quantum mechanics. Not so awesome for everyday measurements

[Arugela]

On 12/30/2013 at 3:45 PM, ZedNova said:

If the metric system had something close to the US Imperial foot, that'd make me really happy.

You could just revert back the imperial system.

It's amazing how fragmented the metric system is. Yet the imperial systems seems to have ironed this out. It's almost like it's more ancient use has gained a natural advantage. And, on top of it all, it allows you to drive humongous fuel guzzling behemoths as a natural right while driving around 2880 miles of natural beauty and splendor. Remember, to conserve you must first feed nature properly. And what do trees and plants like more than the exhaust of a massive car engine. If you do it right you will never run out of trees. Or even potentially be able to cut them down for the abundance of their girth!

I just noticed. Happy necro day!!

Edited May 21, 2023 by Arugela