Liter Vs. Cubic Centimeter

[Johnny Pneumatic]

OK, as geni explained to me a while back the Liter was originally defined to an incorrect value. I learned in school that the Liter is equal to 1,000 cubic centimeters. Is this the corrected version or am I in error? If it is the corrected version then why don't we call 1,000ccm a Liter, it's shorter. Being that I live in a backwards country and thus don't have to use metric that often(though I love it) please check my units of measure.

Meter: Length

Gram: Mass/weight

Kelvin: Generally used to measure cold temperatures

Celsius/Centigrade: Temp.

Pascal: A unit of pressure equal to one newton per square meter.

Newton: The unit of force required to accelerate a mass of one kilogram one meter per second per second, equal to 100,000 dynes.

Tesla:The unit of magnetic flux density in the International System of Units, equal to the magnitude of the magnetic field vector necessary to produce a force of one newton on a charge of one coulomb moving perpendicular to the direction of the magnetic field vector with a velocity of one meter per second. It is equivalent to one weber per square meter.

Dyne: A centimeter-gram-second unit of force, equal to the force required to impart an acceleration of one centimeter per second per second to a mass of one gram.

Barn: A unit of area equal to 10-24 square centimeters, used to measure cross sections in nuclear physics.

Calorie: Any of several approximately equal units of heat, each measured as the quantity of heat required to raise the temperature of 1 gram of water by 1°C from a standard initial temperature, especially from 3.98°C, 14.5°C, or 19.5°C, at 1 atmosphere pressure.

Kilo-calorie: Food Calorie

I know I must be missing some units that I haven't had to use yet. What are they?

[geni]

The most obvious ones you missed out are ampere, mole and candela. The Calorie is not SI. What you are calling a barn should be a square yoctometre.

A litre does equal one decametre however it didn't until 1964 for this reason decametres are often used instead to aviod confusion.

[Jorghnassen]

The Kilogram, not the gram, is the standard unit for mass, not weight (technically, Newtons are the units for weight if I recall my high school physics correctly, but most people don't care about the distinction between mass and weight, hence the confusion). And yes the liter is 1000cc's. Celsius are not technically SI, but nobody uses Kelvin for weather reports...

[Jeff Corey]

Originally posted by Jorghnassen
... Celsius are not technically SI, but nobody uses Kelvin for weather reports...
Absolutely.

[epepke]

Volt. Coulomb. Radian. Solid radian. (OK, the last two are technically dimensionless, but still.)

Of course, the whole set of units is overspecified, and the really tiny discrepancies are due to the fact that the standards are overspecified as well. The kilogram is specified by an artifact, and bits of it fall off from time to time.

When doing physics, I use the MKSA system (meter/kilogram/second/ampere). This isn't exactly the same as SI, but it works for a lot of stuff.

Personally, I think that the Avoirdupois system is unfairly maligned. It has unpleasant bits in it, some of which are arbitrary units and some of which are of the same qualitative nature as the unpleasantnesses that are cropping up in the metric system but much amplified by historically primitive devices.

However, at it's core, it is as physical as the metric system (a pint of water is a pound), and it's based on powers of 2, which are arguably not inferior to powers of 10. The real number 0.1, for instance, cannot be represented accurately on a binary computer.

[materia3]

1000 milliliters (mls) = 1 liter
1 milliter = 1 cubic centimeter (cc)

hence 1000 mls is equivalent to 1000 ccs and herefore a liter is either 1000 ccs or 1000 mls

Centimeters are a measure of length, it is a bit shorter than 0.5 inch. So a cubic centimeter is a cube, a bit smaller than a domino dot sugar cube. A liter is a measure of volume, it is about a quart. A milliliter is one one-thousandth of a liter and is in fact the same volume as a cubic centimeter. A gram is a measure of weight but there is a connection between a gram and a milliliter:

One milliliter of distilled water at 4 degrees celsius weighs one gram.

So one cubic centimeter is one milliter and the weight of one milliter of water is one gram.

[Walter Wayne]

Check here (http://physics.nist.gov/cuu/Units/units.html) for an overview. 41 listed on that page.

And epeke when you say solid radian do you mean steradian. I haven't heard it called solid radian before.

[neutrino_cannon]

I'll be a jerk and point out you missed second.

A kilogram is mass only. Weight is a force, and changes with gravity. Mass is constant, so while you can use kilos for wieght on earth, it isn't technically correct. A Newton would be more accurate.

Also add the Joule if you're so inclined, the unit of energy.

[Ladewig]

Originally posted by epepke
Personally, I think that the Avoirdupois system is unfairly maligned. It has unpleasant bits in it, some of which are arbitrary units and some of which are of the same qualitative nature as the unpleasantnesses that are cropping up in the metric system but much amplified by historically primitive devices.

However, at it's core, it is as physical as the metric system (a pint of water is a pound), and it's based on powers of 2, which are arguably not inferior to powers of 10. The real number 0.1, for instance, cannot be represented accurately on a binary computer.

Surely you're joking. Using a pint of water as (approximately) a pound has produced ounces used to measure weight and ounces used to measure fluid volume: two units with the same name that mean different things.

Powers of 2? 12 inches = 1 foot. 16.5 feet = 1 rod. 40 rods = 1 furlong. 8 furlongs = 1 mile. Oh, and none of these units is tied to the "physical standard" of one pound to one pint.

I have no trouble maligning a system that scientists abadoned in the 19th century. The U.S., Liberia, and Burma are the only three countries in the world that turn their noses up at the metric system. Heck, I'm prepared to malign the Avoirdupois system just for the spelling of its name.

[epepke]

Originally posted by Ladewig
[B]Surely you're joking. Using a pint of water as (approximately) a pound has produced ounces used to measure weight and ounces used to measure fluid volume: two units with the same name that mean different things.

Powers of 2? 12 inches = 1 foot. 16.5 feet = 1 rod. 40 rods = 1 furlong. 8 furlongs = 1 mile. Oh, and none of these units is tied to the "physical standard" of one pound to one pint.

I did say that there were arbitrary units in this. You can concentrate on those if you want to say that it's bad. Hooray, you win!

But 4 ounces is a gill. Two gills is a cup. Two cups is a pint. Two pints is a quart. 4 quarts is a gallon. Two gallons is a peck. Four pecks is a bushel. Two bushels is a barrel. Two barrels is a hogshead.

Powers of two.

Yeah, it's gotten off. For example, the standard hogshead in the US is 63 gallons, not 64. But that's a historical accident, based on the fact that people back then couldn't make stuff that was worth a dam.

But the basic idea was quite sound and not obviously inferior to the metric system. And the metric system is a bit off, too, but we happen to have better machinery now.

[MRC_Hans]

I think the old feet and inch system is much more pictoresque. And as such fitting for a midieval culture like that of the US (see the creationism poll thread ;)). And of course the charm that it is not standardized, so that a mile is not necessarily the same distance in all countries, etc.

Hans :D

[fishbob]

The absolute most annoying units??

International Units.

Vitamin D comes in IUs. Which are different than the IUs for vitamin C with is different for all the other nutrients.

THIS IS NOT PROGRESS.

The evil apothacarians that unleashed this on the world should be forced to . . . . . ingest a peck of pickled peppers in suppository form. There - how many IUs was that??

[neutrino_cannon]

Originally posted by MRC_Hans
I think the old feet and inch system is much more pictoresque. And as such fitting for a midieval culture like that of the US blah blah blah, the Americans are backwards. I'll go get my metric-sized love-doll and revel in my smugness.

For that I shall give you such a spanking you won't be able to go within a cubit of a chair for a fortnight!

[Trinity]

In one place i used to work we had a joke of using silly measuring units. Like speed in furlongs per decade, amounts in fractions of scores and such.

Trinity

[jj]

Originally posted by Trinity
In one place i used to work we had a joke of using silly measuring units. Like speed in furlongs per decade, amounts in fractions of scores and such.

Trinity

Ahh, yes, after all, units of 1/2688 Mile Per Hour...

It's useful if we're discussing hte USPS, I suppose.

[Capsid]

The absolute most annoying units??

Are you saying that one International Unit for say vitamin D should be equivalent to one International Unit foir vitamin C? How would you measure that they were equivalent and why would you need to?

[Soapy Sam]

Originally posted by Jorghnassen
... Celsius are not technically SI, but nobody uses Kelvin for weather reports...

...well, not on Earth, certainly.


Let's hear it for the metric system which has made mental calculations so simple that even smart people can do them rapidly and only be wrong by three orders of magnitude.

[rppa]

Originally posted by SkepticJ
OK, as geni explained to me a while back the Liter was originally defined to an incorrect value. I learned in school that the Liter is equal to 1,000 cubic centimeters. Is this the corrected version or am I in error? If it is the corrected version then why don't we call 1,000ccm a Liter, it's shorter. Being that I live in a backwards country and thus don't have to use metric that often(though I love it) please check my units of measure.

I recall something about this in the history of the liter as well, but I wasn't able to track it down in a little bit of googling. At any rate, its current status seems to be that it is exactly 1000 cm^3 and accepted for use in conjunction with the SI system, but not recommended as an official unit of volume. I think it's not just a question of "shorter" as that the idea is to have only a few standards on which these things are based. So volume is defined in terms of length.

I don't think the original definition was a "mistake" so much as inaccurate. Generally when units are redefined they try to keep the new value close to the old value, but replace the calibration with a more repeatable standard. The liter was originally defined in terms of the volume of a kg of pure water under certain conditions of temperature and pressure, but that's not accurate enough.

[Anders W. Bonde]

One of the more amusing units is the old slug feet - seems a bit of an oxymoron to me...

In engineering, Europe uses the millimeter as the basic unit of length - which is fine if you're a watchmaker: There seems to be a lot of millimeters involved when you are into designing, say, the Airbus A380. I've worked equally much with American aircraft, which are done in inches, which is to me a much more manageable basic unit, physical size-wise. I sometimes wish that the European engineers had adopted the centimeter instead (like the carpenters seem to use), but it doesn't fit in with the basic SI scaling by 1000 of magnitudes.

Shoot me for being a living dinosaur: I actually like working in fractions of inches - you can always keep dividing by two (which is good for scaling and particularly good for symmetry) to get the 'nice, round, whole' fraction you need - even when writing them as decimal inches (which is actually done nowadays!). I also find it neat that 3/8" rounds off to .38" - FWIW.

[exarch]

One of the things we were taught in design school is to never make models or drawings on a scale of 1/2 or 2/1, because the model will be too close to actual size and not obviously be a scale model. It's better to actually make something life-size in that case, or go to a scale of 1/5.

I assume a similar problem could arise when confusing units that are seperated by an order of magnitude of 2, whereas it's pretty obvious when you're off by an order of magnitude of 10. Everybody will realize right away there's something strange going on if the base of your house measures only 1,5 by 2 meters, or 150 by 200 meters. (in architecture, the basic unit is usually the centimeter, while in engineering it's the millimeter, so it's not entirely inconceivable for a technical drawing to be in a wrong base unit).

As for airbus components, a crucial part could be 'just a little over 3 inches' or '78 millimeters'. When accuracy is concerned, I think basic measurements that are smaller are more manageable and easier to calculate with than 3 1/16".

[Darat]

litre

[Khonshu]

"Everybody will realize right away there's something strange going on if the base of your house measures only 1,5 by 2 meters, or 150 by 200 meters."

Or your model of StoneHenge could be in danger of being crushed by a dwarf...

[fishbob]

Are you saying that one International Unit for say vitamin D should be equivalent to one International Unit foir vitamin C? How would you measure that they were equivalent and why would you need to? Argh - they are not equivalent. One prevents scurvy and the other gives me strong bones and healthy teeth and I can't figure out how many mg or cc or piconewtons/furlong I'm supposed to take.

And this gives me a headache, so I need some aspirin (not Tylonal dammit) and they used to be measured in mg and now some are and some aren't. Then ask a medical professional sometime 'what is an international unit'. See what kind of non-answers YOU get. And then the headache gets worse.

Beer is measured in liters or ounces. I can deal with that. Thanks for reminding me.

[Capsid]

Argh - they are not equivalent. One prevents scurvy and the other gives me strong bones and healthy teeth and I can't figure out how many mg or cc or piconewtons/furlong I'm supposed to take
I was referring to the equivalence of the International Unit not the compounds they measure. International Units measure the activity of the substance which is far more relevant when testing for them.

[Anders W. Bonde]

Since I'm so far off-topic anyway:

Yeah, 1/5 is a pretty neat scale: Multiply by 2 (add to self) and move the decimal one notch to the right - no calculator needed.

Of course, in this day and age with CAD/CAM it doesn't matter, as you model everything full scale anyway and then just scale drawings or models subsequently. In engineering we use both 2/1, 1/2, 1/4 (US), 1/5, 1/10 and 1/20 scale plots - all depending on the size of the product versus the drawing/plot format size.

Re. Airbus component slightly longer than 3 inches: Assuming it's a structural component, we tend to work with general tolerances, which are classed by the number of decimal places called out in the dimensioning on drawings.

Assuming a general tolerance of +/- .010" or +/-0,25mm (a pretty typical 'close' structural tolerance), a part 3-1/16" dimension would today be written 3.063"; the metric equivalent would be 77,79 mm; no difference in practicality. However, using a typical larger tolerance of +/-.03" or +/-0,8mm, the figures are: 3.06" and 77,8 mm: Note the consequence of roundig off the decimals by the tolerance; here the inch-figures are actually of a more appropriate and IMHO intuitively correct magnitude, if we look at the max and min limits: 3.03" to 3.09" versus 77,0 mm to 78,6 mm.

In (European) aerospace we also work with what we call 'bastardized metric', which is US dimensionsioned parts annotated in metric, typically fasteners (the US is the market leader in aerospace fastening systems) and avionics cabinet interfaces. So, we have like 3,2 mm and 4,8 mm rivets (1/8" and 3/16"), and even bolts with 6,35 mm threads with 28 threads per 25,4 mm (although it is usually written .250"-28). Russia, France and Sweden used to build all-metric aircraft, but today even Airbuses and the SAAB/BAE 'Gripen' use US fastening hardware in inch-sizes: There's more of it out there than metric, the users have the US stuff in their workshop inventories and the US fasteners are usually cheaper due to the far greater availability.

I'll leave it at that.

[wollery]

Metres, kilograms, litres, seconds, Pah! Puny units. :D
I deal in parsecs, solar masses, cubic parsecs and megayears! Now there's some big units for ya! :p

ps In the UK, although we're officially an EU state and, therefore, supposedly metric, most of our stuff still runs on the imperial system. Distances are measured in miles, beer and milk come in pints, people measure their height in feet and inches and their weight in stones and pounds, and most over the counter foods are still sold in pounds and ounces.

We did, however, change do a decimal currency system over 30 years ago.

[Matabiri]

Zeptolitres (http://news.bbc.co.uk/1/hi/sci/tech/4033641.stm) make it to the BBC news page.

[Deetee]

Quote:
"The zeptolitre is currently the second smallest defined unit of volume."

What's the smallest then?

[Darat]

Originally posted by wollery
...snip...

ps In the UK, although we're officially an EU state and, therefore, supposedly metric, most of our stuff still runs on the imperial system. Distances are measured in miles, beer and milk come in pints, people measure their height in feet and inches and their weight in stones and pounds, and most over the counter foods are still sold in pounds and ounces.

We did, however, change do a decimal currency system over 30 years ago.


PPS.

I take it there is a Mrs (or Mr) Wollery that does the shopping for your household? ;)

Go to any supermarket and you won't find milk sold in imperial units, even sugar is now sold by the kilo and over the counter foods are sold by metric units. (You'll become a criminal if you try and weigh out a pound of apples to sell to someone nowadays!)

[wollery]

Originally posted by Darat
PPS.

I take it there is a Mrs (or Mr) Wollery that does the shopping for your household? ;)

Go to any supermarket and you won't find milk sold in imperial units, even sugar is now sold by the kilo and over the counter foods are sold by metric units. (You'll become a criminal if you try and weigh out a pound of apples to sell to someone nowadays!) No, there's no significant other, so I have to do all the shopping. My milk is delivered by the pint, and I buy my cheese and meat by the pound (or fractions thereof) over the deli counter at Asda. It may be priced by the kilo, but if you specify how much you want in imperial units they don't bat an eyelid, they just get on with it. The legal standpoint is that the principle pricing signage, and the receipt, must be in metric units. It isn't illegal to weigh out the goods in imperial, provided that they're also weighed in metric for the purposes of calculating the price.

Edited to correct stunningly bad typo!

[Matabiri]

Originally posted by Deetee
Quote:
"The zeptolitre is currently the second smallest defined unit of volume."

What's the smallest then?

A yoctolitre.

"cubic -/m tetrahedron = Goddess of Liberty (or Prosperity/Earth) & Blue Dimension (1st Dimension)" (http://www.weights-and-measures.com/xnerefldry.html)

[Ladewig]

Originally posted by epepke
I did say that there were arbitrary units in this. You can concentrate on those if you want to say that it's bad. Hooray, you win!

But 4 ounces is a gill. Two gills is a cup. Two cups is a pint. Two pints is a quart. 4 quarts is a gallon. Two gallons is a peck. Four pecks is a bushel. Two bushels is a barrel. Two barrels is a hogshead.

Powers of two.

Yeah, it's gotten off. For example, the standard hogshead in the US is 63 gallons, not 64. But that's a historical accident, based on the fact that people back then couldn't make stuff that was worth a dam.

But the basic idea was quite sound and not obviously inferior to the metric system. And the metric system is a bit off, too, but we happen to have better machinery now.

Of the five most common measurements in daily life, distance, area, volume, weight, and fluid volume, only the last comes close to powers of two. The others show no regular method of unit multiples.

Compare the difficulty in calculating the number of square feet or square yards in a square mile to calculating the number of square meters in a square kilometer. Consider the difficulty in determining how many times 7 5/8" goes into 9 feet.

I am prepared to say that the Avoirdupois system is inferior to any system based on powers of ten.

[Hydrogen Cyanide]

Originally posted by Jorghnassen
The Kilogram, not the gram, is the standard unit for mass, not weight (technically, Newtons are the units for weight if I recall my high school physics correctly, but most people don't care about the distinction between mass and weight, hence the confusion). ...

Any engineer concerned with structural dynamics does worry about mass versus weight... and forcing functions.

So to add to the weird unit vocabulary:

kip = 1000 pounds -- a unit of force

slug = 1 lb/(32.2 ft/sec sec) -- a unit of mass

slinch = 1 lb/(386.4 in/sec sec) -- a unit of mass

A slinch is also called a "snail".

And because I did work for a local aerospace company... we worked in "knots", which are nautical miles per hour. (and since I worked on landing gear, it was fun seeing test data of a landing 757 screaming down the Moses Lake runway at 250 knots!).

Note of clarity: I have not worked in over 16 years, this bit of memory was brought up last night while discussing units with #2 son.

[Ove]

Kilo-calorie: Food Calorie

Ahh but you MUST use KiloJoule instead and also ude Kw instead of Hp .
I prefer Tonnes in the weight scale, that means i weigh 0,086Tons which sounds fine to me.:D

[Matabiri]

Originally posted by Ove
Ahh but you MUST use KiloJoule instead and also ude Kw instead of Hp .
I prefer Tonnes in the weight scale, that means i weigh 0,086Tons which sounds fine to me.:D

A tonne (= 1000 kg) isn't the same as a ton (= 2000 pounds).

[richardm]

Originally posted by Matabiri
A tonne (= 1000 kg) isn't the same as a ton (= 2000 pounds).

So much so that on the Berwick docks the guys operating the cranes will pronounce them "Tunneys" and "Tons", just to make sure that there's no mistakes made.

[Matabiri]

Originally posted by richardm
So much so that on the Berwick docks the guys operating the cranes will pronounce them "Tunneys" and "Tons", just to make sure that there's no mistakes made.

I also used the wrong conversion table (darn Google calculator!), and feel very bad about it.

A ton is 2,240 pounds. An American ton is 2000 pounds.

[exarch]

I've never heard it called "tonnes", although I know they sometimes call it "metric tons".

[a_unique_person]

Originally posted by MRC_Hans
I think the old feet and inch system is much more pictoresque. And as such fitting for a midieval culture like that of the US (see the creationism poll thread ;)). And of course the charm that it is not standardized, so that a mile is not necessarily the same distance in all countries, etc.

Hans :D

Nor is the gallon.

[bjornart]

Originally posted by a_unique_person
Nor is the gallon.

What distance is the gallon in Australia then? :D

[Matabiri]

Originally posted by bjornart
What distance is the gallon in Australia then? :D

About the distance from the bar to the urinal.

[H3LL]

It's all nonesense...

The most popular measurements are:

Tad, smidgin, bit, tick, finger, beer, yonk, ages, whisker, little bit, bit more, pace, step, mo', ton, gallons, squeek, pinch, close and donkey's years....to name a few.

[richardm]

Originally posted by exarch
I've never heard it called "tonnes", although I know they sometimes call it "metric tons".

That's a whole extra syllable on top of "Tunney", and stevedores are men of few words ;)

[Matabiri]

Originally posted by richardm
That's a whole extra syllable on top of "Tunney", and stevedores are men of few words ;)

Mostly, they just call themselves "Steve".

[richardm]

Originally posted by Matabiri
Mostly, they just call themselves "Steve".

Or "Dora". But that might just be in Berwick.

[Ove]

A tonne (= 1000 kg) isn't the same as a ton (= 2000 pounds).

Well a Danish pound IS 500g and a Danish TON is 1000kg so i should be forgiven. I KNOW that there are a thing called "BRT" (Brutto Register Tons) that are used in maritime circles but i really have no idea how it works. But i maintain that according to Danish weightscale i weigh 0,084T which sounds quite comforting to me.
A well known Danish singer once made a remark about male weight, he said :"Anyting below 100kg is feminine", he was also known to be suffering from bullemia he just forgot the throwing-up part of it.:D

[epepke]

Originally posted by Ladewig
Of the five most common measurements in daily life, distance, area, volume, weight, and fluid volume, only the last comes close to powers of two. The others show no regular method of unit multiples.

Dry volume units are a little different, but they still are based on powers of two.

Distance units an inch and below are powers of two. With foot and yard, factors of 3 are introduced. But a half yard is still a cubit. Fractions of miles are given as powers of two. Nobody knows what a rod or chain is any more.

Weight is based on powers of two. 16 ounces make a pound.

[Ladewig]

epepke
Dry volume units are a little different, but they still are based on powers of two.

Obsolete dry untis are based on powers of two, but no one uses pecks and bushels anymore. Volume is more often measured in cubic inches and cubic feet (e.g. A Buick 401 cubic-inch V-8 engine).

Distance units an inch and below are powers of two. With foot and yard, factors of 3 are introduced. But a half yard is still a cubit. Fractions of miles are given as powers of two.

But fractions of miles are just as often given in tenths.

Weight is based on powers of two. 16 ounces make a pound.

The smallest commonly-used measurement is 1/16 the next smallest commonly-used measurement. The next interval is 1:2000. 1:16 and 1:2000 cannot be described as a scale based on powers to two.

[wollery]

Originally posted by epepke
Weight is based on powers of two. 16 ounces make a pound. And 14 pounds make a stone, 160 stones to a ton, 112 pounds to a hundredweight.

What's your point again?

[Soapy Sam]

They're all perfectly divisible by two.
What'cha mean, "whassa point?"

[wollery]

Divisible by two maybe, but they sure as heck ain't powers of two, which is what he said.