Talk:Litre

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[edit] How old?

See http://www.npl.co.uk/npl/reference/international.html for 1979 acceptance of L as well as l. Hotlorp 23:29 Feb 14, 2003 (UTC)

The year of 1901 cannot be right, can it? I thought the Imperial gallon being defined by so and so measure of water was inspired by the metric definition of a litre, so it must have been at the start of the 18th century -- Egil

You are right: the litre is older than 1901. See the current article. -- Heron

[edit] Kilolitre

Added kilolitre - my water bills in Australia used to measure consumption in kilolitres. - David Gerard 12:54, Jan 28, 2004 (UTC)

[edit] Circular dependency?

Nothing depends ON litre, so no matter what litre depends on, there cannot be any circular dependency, can it? --Mormegil 10:21, 10 Aug 2004 (UTC)

Good point, removed this from the article. Paranoid 18:57, 20 Nov 2004 (UTC)

[edit] Reasons for redefinition

Does anyone know why the litre was redefined in 1901? It doesn't make any sense to me, when you had a perfectly good definition based on the metre. Paranoid 18:57, 20 Nov 2004 (UTC)

It was indeed rather senseless, IMHO, but the CGPM did finally come to their senses and "abrogate" that definition (that's how it is phrased in the legalese of their resolution).
Originally, it was intended that the gram should be the mass of a cubic centimeter of water; so obviously the length standards were constructed first. But then, way back in 1799, the original platinum cylinder known as the Kilogramme of the Archives was constructed by the French government to serve as the mass standard. Since then, the definition of the kilogram has never been officially based on water.
After the Metre Convention (or Treaty of the Meter) of 1875, the organizations known as the CGPM and BIPM were formed. They has a new set of international standards for the metre and the kilogram constructed, placing them in use in 1889. In constructing this new platinum-iridium International Prototype Kilogram and its siblings which serve as national standards, the target was the old French standard—not water.
But by then, in the late 19th century, people had been able to make better measurements of the density of water, at its maximum density and throughout the temperature ranges of liquid water, and were well aware of the discrepancies between the actual kilogram, and what it would have been if the 18th century French technicians had been able to carry out these measurements more precisely in constructing their kilogram.
Obviously, there were some users in the science who thought it was terribly important to have that exact relationship with water at its maximum density. So the CGPM let itself be talked into this hairbrained scheme of redefining the litre to make that true (I wouldn't call it that in the article, but am expressing my opinion of it here on the Talk pages).
Note that this is a flip-flop of the original intention of defining the unit of mass based on the cube of the unit of length. In 1901, they instead redefined the unit of volume based on the unit of mass.
Cubic centimeters, of course, remained the cube of the length units. So for a couple of generations or so, we students had to waste a lot of time learning that they were not the same thing as milliliters. Never mind that there had only been a handful of measurements in the history of the world where it ever made any difference.
There was, of course, a similar discrepancy in the construction of the original metre, from their very good but not as good as today's efforts to measure the meridian quadrant, and as a result there are actually 10.002 Mm from the equator to the poles, rather than the intended 10 Mm exactly. Fortunatly, the CGPM never got talked into any scheme to add another new length unit to use alongside the metre, but equal to 1.0002 m.
Note that I have removed an erroneous claim in the article as I found it that the intent in 1901 was that the 1901 definition would be the same as a cubic decimetre. It was well known that it would not, and that in fact was the entire purpose of that redefinition, to make it different from the cubic decimeter which for water never quite gets up to that 1.00000 kg level under one atmosphere of pressure, even at maximum density. Gene Nygaard 03:12, 13 Dec 2004 (UTC)

[edit] Symbol mL

CGPM in 1979 said:

considering further that in the future only one of these two symbols should be retained, invites the CIPM to follow the development of the use of these two symbols and to give the 18th CGPM its opinion as to the possibility of suppressing one of them.

The CIPM, in 1990, considered that it was still too early to choose a single symbol for the litre.

The United States National Institute of Standards and Technology recommends the use of the uppercase letter L.

Uppercase L has become the preferred and more common symbol in US & Canada. It only makes sense that the others (mL) use capital too - otherwise there's confusion.

Are there any standard bodies recommending lowercase be retained?

I'd say "the handwriting is on the wall" - there's not a chance in hell that lowercase will be the single symbol --JimWae 18:50, 2004 Dec 14 (UTC)

Medical fields find that using L is preferable. Less likely to misread a report of 1l in a column of data as meaning 11. I teach metrology often to students going into medical professions, and the current texts have all adopted L along with mentioning anecdotes of cases where the 1/l confusion caused interpretation errors.--Sturmde 19:42, 9 November 2005 (UTC)

Well, for me using lowercase l all the time, it was a big surprise that somebody uses a big L for the liter/litre? But this is actually a very small issue between english speaking people and others. The more confusing thing is that you guys are using decimal point as we are using decimal comma, and all texts and programs should to be able to make the conversations. In the spreadsheet world this is solved but with text editors one has to make the change manually. --Jabamula 21:14, 20 December 2005 (UTC)

[edit] Capacity v. Volume

Can anyone give a practical or commercial case in which the litre is used for solids? --JimWae 18:50, 2004 Dec 14 (UTC)

Certainly. Grain might flow, but it is not a fluid. Same goes for blueberries (where in the U.S., the 1 pint packages also include 551 mL right on the label, for example). Gene Nygaard 20:58, 14 Dec 2004 (UTC)
Here's another example, from http://www.stainless-steel-world.net/titanium/automotive.asp

Comparison of specific strength of engineering alloys

Material Density
kg/l		 Youngs

Modulus

GPa		 Yield Strength
MPa		 Specific Strength
CP Titanium 4.51 105 250 - 450 50 - 100
Ti-6Al-4V 4.43 112 900 - 1100 200 - 250
Ti - LCB®® 4.79 110 950 - 1400 200 - 290
Carbon Steel 7.8 200 350 - 450 45 - 60
Aluminium Alloy 2.8 70 100 - 350 35 - 125
Gene Nygaard 21:18, 14 Dec 2004 (UTC)
The capacity of a garbage bag is not the measurement of a fluid. Sure, it is the volume of a fluid such as air which would fit into it. But that's not usually what we use our garbage bags for. Gene Nygaard 21:41, 14 Dec 2004 (UTC)

I guess it could be different in different countries, but we do not buy rice or wheat or or candy or aluminum by the litre in Vancouver - not retail, & I doubt wholesale too.

Blueberries & strawberries come in CONTAINERS with a certain mL capacity ( I notice you used mL too) & no weighing is then needed. Would anybody really expect they are getting 551 mL of blueberries without the air?

I think derived units for density using kg/L might stay current because it is an obvious way to compare to water that way.

I was taught litre was for capacity (and "fluids" & even small solids that flow that are not normally counted & usually get no indefinite article; e.g rice - not a rice, but yes an apple), m^3 was for volume. Though it is not a hard & fast rule, it is noteworthy enough, I think, to include somewhere in the encyclopedia (admittedly, not in the definition) - and I think clearer.

It's wrong. There is no distinction between capacity and volume in the metric system. Blaise 22:45, 23 May 2006 (UTC)

The Wikipedia isn't just a British Columbia project.
Look at any Canadian table of conversion factors for bushels (at least by anyone not smart enough to know that most of the bushels we use today are units of mass). What are the metric units used? What do we measure with bushels?
Google bushel hectoliter OR hectoliters OR hectolitre OR hectolitres OR hektoliter
The site http://www.bcblueberry.com/processors/production.htm tells us that

"Fresh BC blueberry packages include:

  • five and ten pound bulk cases,
  • and trays containing twelve one-pint
  • or twelve half-pint units and other sizes."
    Of course, there are a couple of differences between your British Columbia blueberry boxes and mine in the United States:
    1. Those Canadian containers do not include the word "pint" or an abbreviation of it on the label.
    2. Those pint containers are 568 mL rather than 551 mL. That's because you use those dinky little litres instead of the hefty liters we use, isn't it?  :-)
    That there are air spaces among the berries does not mean that you are measuring a fluid.
    For wheat in Canada, the "test weight" (a measurement of bulk density, used as a quality factor) is still very often measured in pounds per U.S. bushel (rarely if ever per imperial bushel). But you also see it expressed in metric units, such as the "kg/hl" at http://members.shaw.ca/bethcandlish/swht1.htm
    Yes, I used mL too. But I when I commented on your web page, what I said is that it is not good form to change someone elses "ml" to "mL' in Wikipedia. (Trying to achieve consistency within one article might be acceptable, not just flip-flopping from one to the other). For this particular article, and probably not any other, I think it would be a good idea to include both in all uses, but I'm not going to add that now.
    Those density usages are quite relevant to the untruth of the limitation you claim.
    Whoever the anonymous person was who deleted your statement about liters only being for fluids got it right. (Well, actually I'm just assuming you are the one who put it in there; it doesn't matter enough to me for me to go and confirm that--it's good riddance to misinformation in any case.) Gene Nygaard 01:25, 15 Dec 2004 (UTC)

    OK, I'll agree "for fluids" was incomplete. It is also incomplete to leave it open to use litres for measuring quantities like solid metals.

    Litres (& mL & kL) are used for things that are measured by the capacity of their containers - usually (but not exclusively) things that can be poured & that are non-count nouns (and usually in English anyway, get no indefinite article).

    Water in a swimming pool would then be measured in litres, water falling over Niagara in m^3 - You will rarely see waterfalls measured in litres (though of course some will do so) -- the water is not in a container.

    There may be exceptions to this too, but it is still noteworthy in an article about litres.

    Only if it is true! There is no support at all within ISO 1000 or ISO 31 for any interpretation that litre and cubic metre measure different things. There *is* such a distinction in Imperial units, but the distinction simply does not exist in metric Blaise 22:59, 23 May 2006 (UTC)


    Noting also: Many things that can be poured are sold by mass anyway.

    A note was deleted which stated that the unit of volume in the SI is the m3. This should be reinstated. It is correct. The m3 is the derived unit of volume in the SI. NIST note on SI units

    The liter is defined as one of the "Units outside the SI that are accepted for use with the SI." It is not, strictly speaking, a unit in the SI, and should not be represented as such. NIST note on units outside the SI.

    I also find the statement above, "Litres (& mL & kL) are used for things that are measured by the capacity of their containers" to be very dubious. Can the author point to *any* publication by any authorative standards body that states this? I've never seen such a thing, and would find it hard to believe that any standards body created another unit of measure for volumes strictly based on intent. --Eliasen 03:08, 19 Dec 2004 (UTC)

    You have said

    • The liter is defined as one of the "Units outside the SI that are accepted for use with the SI."

    Whereas The 12th Conférence CGPM does not even define the litre, saying that it

    • declares that the word “litre” may be employed as a special name for the cubic decimetre,

    so it does not DEFINE it at all, but gives an equivalancy in common use - it certainly does not define it "as one of the units outside the system", but further declares

    • that the name litre, although not included in the Système International d’Unités, must be admitted for general use with the System,

    I've lived in a country that has used SI for 30 years. No current standards body created the litre - it is simply a unit in common use that "must be admitted for general use with SI - just like the minute and the day

    The unit is not based on intent but on how the measurement is done.

    If L (or mL or kL) are used, then (at least most likely) it has been measured by the size of the container it is in.

    If kg are used, the expectation is that its weight or mass have been measured.

    If m3 is used then (at least most likely) its dimensions have been measured -- OR its displacement.

    I am really quite surprised that I cannot find a standards body that distinguishes capacity from volume -- What is the volume of a cubic container each of 6 sides a square of 11x11 cm, with each side 5 mm thick? What is its capacity? Remove 1 side and recalculate. There's some difference between volume & capacity, right?

    I guess the standards bodies just do not want the added responsibility of defining a litre or its uses - so it would seem we cannot appeal to standards bodies but only to common usage Or perhaps it just is not their venue to make the distinction, maybe it's up to linguists or philosophers. --JimWae 05:38, 2004 Dec 19 (UTC)

    As I understand it, there is no distinction in physics between capacity and volume units. Even in colloquial use, there is no real distinction. For example, people will accept that an engine 'capacity' can be described as 1.2 L (litre units) or 1200 cm³ (m³ units). It is interesting that we don't talk about a 1200 ml engine. Luggage and rucksacks are described in litres and so are car boots. However, aircraft containers for luggage are described in cubic metres. It is just a matter of size, history and application.
    Ice cream and butter have similar consistency. Ice cream is described in litres in the UK, although butter is described in grams. Perhaps it is partly because ice cream is manufactured as a liquid. If I understand it correctly, medical people in the US used to measure liquid dose in 'cc' and had measuring devices with interior volume calibrated in cm³. I understand now that they use litre based units (mL) in the US (as does the UK).
    The term 'capacity' means interior volume. The term 'volume' could be applied to interior or exterior volume. My thoughts in summary are:
    1. People describe volume as 'volume', 'capacity' and 'displacement'.
    2. People use units such as 'm³', 'litre', 'cc', 'ml', 'cm³', 'ton'.
    3. You can sometimes link a description to a unit (displacement = 1100 cc) in a domain and a region but is more of an art than a science. Bobblewik 19:47, 21 September 2005 (UTC)
    The U.K. sold ice cream in English units for many years before they ever started to use litres for this purpose. Just as in the United States, only even more so because they have smaller fluid ounces, the reason ice cream is sold by volume is that you get more "ounces" that way, because the density of ice cream is less than 1 oz/fl oz, even for the bigger U.S. fluid ounces. That's also why in the United States, evaporated milk is sold by the fluid ounce (i.e., by volume, with milliliters on the label as well), but sweetened condensed milk is sold by the avoirdupois ounce (i.e., by mass, with grams on the label as well). It has little or nothing to do with the texture and consistency of the product. Gene Nygaard 02:50, 16 October 2005 (UTC)
    You are confused, JimWae. Standards agencies do define the liter. The 12th CGPM in 1964 did so, when it abrogated it's own definition from the 3rd CGPM in 1901, restoring it to the definition CGPM inherited when it was founded. Note also that though the liter is not an SI unit, and never will be, the CGPM since the introduction of SI has on three different occasions, IIRC, acted with respect to the non-SI liter. Gene Nygaard 03:21, 22 September 2005 (UTC)


    The litre, as meant since the original metric system of 1791 was a unit of capacity, meaning what a container might carry. The volume of the contents will usually be less than or equal to the capacity of the container due to the spaces in between the water. For example, a 1 litre container might be full of berries and you could still pour water on it without overflowing the container.

    The original system also had a named unit of volume which was the stere which is equivalent to a cubic meter, as it has a unit of area, the are which is often used as the hectare in the measurement of terrain, which in my city is about 1 city block == 1 hectare or about twice a football field, that is, a square 100 metres on a side.

    So, since the litre remains with us mostly for historical reasons and as a shorthand for a cubic decimetre, let us keep its original intent in the definition, there was something else for volume and it was not the litre

    --DevaSatyam 18:09, 15 October 2005 (UTC)

    [edit] Standard litre per hour

    Can someone explain me what is the difference between litres per hour and standard litres per hour. In fact, I am confused over the calculation of volume and pressure of gas with Boyle's law.

    You need to provide a bit more context information to make your question meaningful. I suspect, that with "standard litre", you could mean a liter of some gas or liquid, where the volume is measured at some standard temperature and pressure (which one?). Markus Kuhn 1 July 2005 19:35 (UTC)

    Yes, I needed to provide more info in fact I meant it STP. I am designing a high pressure skid for CO2 gas, where the gas is to be compressed to 350 bar pressure, and the same is to be injected in to extruder at a flow of 3 kg/h, the barrel of the extruder is having a temp. of 150 °C. I am using a gas booster for the same. I want to know whether the gas under compression will go in to liquid state, and secondly in the compress state how do I calculate the temp. at various pressure. Secondly what care has to be taken from safety point. Thanks for your reply. 22nd July'05 Hitesh Mody.

    A phase diagram of CO2
    Enlarge
    A phase diagram of CO2
    Hm, sounds to me you are looking for a phase diagram of CO2 (and perhaps even for a chemical engineer as a consultant). Not really related to an encyclopedia entry on the litre ... Markus Kuhn 13:11, 22 July 2005 (UTC)

    [edit] Why is it spelled "litre" anyway?

    I'm just curious as to why the Commonwealth spelling of "liter" is "litre". I've noticed that if you said "litre" as it was spelled, it would come out as "lit-tree" instead of "lit-er". Why is that? --ApolloBoy 05:57, 25 September 2005 (UTC)

    Notice also that if you pronounced "liter" as it seems to be spelt it'll come out as /li:t@(r)/ (in X-SAMPA). 26Oct05 i.e. (for most of us) it would be a homophone with lighter. Jimp 16Dec05

    I wonder too why is it spelled "Litre" (British spelling I think) and not the common "Liter"? (same with metre-meter article) Yonir 11:30, 25 September 2005 (UTC)

    English orthography is more etymological than phonological—as is French, where “litre” came from (although with a latinised Greek root). American English orthography tries to be a little bit more phonological. That works in the (probably most prominent) case of -re vs. -er or “gramme” vs. “gram”, but fails horribly with words like “night” vs. “nite” (should rather be something like “nait”), which is luckily not (yet) widely used.
    Whether AE or BE is used in a Wikipedia article mostly depends on the main/first author(s), see the MoS. For litre this also applies to its symbol, which is either l or L. Christoph Päper 15:57, 25 September 2005 (UTC)
    No, "nite" would be perfectly fine for "night" according to the rules of English orthography. Only the Americans don't officially use "nite". Jimp 26Oct05
    On the other hand, one could wonder whether American English really deserves to have different spellings for measures which Americans refuse to adopt. ;) - toh 16:20, 3 October 2005 (UTC)
    That's the best thing i've heard for ages, bravo! -- deanos {ptaaglek} 09:37, 4 October 2005 (UTC)
    Typical American thing to do, isn't it? Refusing to adopt the metric system? I'm perfectly willing, but the rest of my country's not. Twilight Realm 03:21, 13 October 2005 (UTC)
    Don't let anybody pull your legs, ApolloBoy and Yonir. The reason is so that we can tell those dinky little litres, where it takes 4.55 of them to make a gallon, from the he-man sized liters we have in the United States, where it only takes 3.79 of those "-er" units to make a gallon.  ;-) Gene Nygaard 04:15, 13 October 2005 (UTC)

    Litre would be the original spelling; liter the U.S. reformulation (Noah Webster?). Same reason we spell battle, buckle, kettle, mettle the way we do. —Michael Z. 2005-10-3 17:42 Z

    Since America doesn't even use the measure, they should not dictate how it should be spelt. -- Dandelions 17:08, 30 May 2006 (UTC)


    Litre would be litra, not lit-tree. 67.188.172.165 01:40, 4 November 2006 (UTC)

    [edit] Merge with mL

    As I was finding the template to merge the millilitre article with this one, someone else went ahead and did it. That surprised me. But anyway, the mL article was almost the same as this one, but there may have been some small details in it that should be included in this one. Could someone check? Twilight Realm 03:19, 13 October 2005 (UTC)

    [edit] mL vs. cm3

    Isn't a millilitre the same as a cubic centimetre? This should be mentioned somewhere, but as I'm not positive, I'm not going to do anything now. Twilight Realm 03:19, 13 October 2005 (UTC)

    They weren't, when I first learned about them. Lot's of effort was wasted teaching a trivial difference, just because some fools insisted on there being something magic about water at its maximum density and standard pressure. They are the same now, however. Gene Nygaard 04:11, 13 October 2005 (UTC)

    [edit] So a liter is 1,000 cubic centimeters?

    So a liter is 1,000 cubic centimeters? That's a lot. How come then, when you buy a one-liter soft drink, the bottle isn't 1,000 centimeters long by 1,000 centimeters wide by 1,000 centimeters thick? Wiwaxia

    Because you've confused "1000 cubic centimeters" with "1000 centimeters cubed." A liter contains one thousand little cubes, each little cube being one centimeter on a side. You could stack them in a larger cube ten centimeters on each side, or in a line one thousand centimeters long but only one centimeter wide. Bryan 00:28, 9 January 2006 (UTC)
    It's actually very simple math. If we take your case of 1000 cm by 1000 cm by 1000 cm, that would be: 1000 cm * 1000 cm * 1000 cm = 1000000000 cm³. Just multiply the numbers and the centimetres. The cubic measure also implies that it takes 1000 cm³ to be equal to 1 dm³, whereas normally you'd only need 10 cm to make 1 dm. --Ajunne 13:42, 17 September 2006 (UTC)
    1 l = 1 L
    = 0.001 m³ = 1 dm³ = (10 cm)³ = 10³ cm³ = 1000 cm³
    ≠ (1000 cm)³ = 1000³ cm³ = (10 m)³ = 1 dam³ = 1000 m³

    [edit] 277.13 K is NOT room temperature!

    0 C=273.15 K, so 277.13 is 3.98 C or approximately 4 C (see wikipedia Kelvin page). I edited out "room temperature" (normally 20-22 C or 293.15-295.15 K) and replaced it with "4 C".

    What does this have to do with liters? 67.188.172.165 23:23, 2 October 2006 (UTC)
    Water is unusual in that it expands both when cooled and heated. (Which is why ice cubes float--they're less dense than water.) 4 C is the temperature at which it takes up the least volume per unit mass. So at 4 C, 1kg of water is exactly 1 litre, which is exactly 10cm3, and that baseline is used to derive much of the rest of the metric system. --HKMarksTALKCONTRIBS 00:48, 3 October 2006 (UTC)
    At approximately 3.98 °C, water is at its most dense at standard (atmospheric pressure). Note that this is not necessarily true for all pressures - according to http://www.lsbu.ac.uk/water/anmlies.html - at pressures around and above 200 MPa, there is no longer a density maximum. Please note, also, that the Celsius scale of temperature uses degree symbols - if you leave them out, you will be referring to Coulombs. WLD 17:03, 3 October 2006 (UTC)
    Yeah, but you know, they're just a pain in the tush to type just for a talk page :P --HKMarksTALKCONTRIBS 19:28, 3 October 2006 (UTC)
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