bill cobbett wrote:Oracle wrote:Phill wrote:Oracle wrote:bill cobbett wrote:Oracle wrote:I hate units of measurement ...
Can anyone explain the difference/similarity between cm cubed and ml?
cm3 = ml
I seem to recall a slight disparity
He's right...
I remember the definition was they were "essentially" the same and this has always irked me!
Why "essentially" ... either they are exactly the same (in which case why use the cumbersome cm cubed?) ... or they have an "essential" difference in usage!
Density, buoyancy and volume!
Had a think and got nowhere so googlied ...
Remarkably there is a difference where really there shouldn't, due to different, unreated standards being used by the blooming French to define the metre and kilogram.
Have to go to 5 decimal places for the diff mind.
Never had this problem with pounds and ounces.
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sequoianoir
Unfortunately, 1ml does not equal 1cc. There is a difference when you go to 5 decimal places.
The metric system has it roots in Paris in 1793. In addition to decimal system proposals, units of length, mass and volume were provisionally created. (A brass standard of the provisional metre was made: it is preserved in the Conservatoire des Arts et Métiers, Paris.) This was when the LITRE was first defined as a measure for liquids, this being an appropriately sized volume for commercial use. As the 19th century drew to a close, very precise measurements were needed in the fields of Physics, Chemistry and engineering. In 1889 the "Standard Kilogramme" was created. This was supposed to be the same as 1 litre of distilled water at its maximum density -ie. at a temperature of 4 degrees celsius. The LITRE then became officially defined as 1 kilogramme of pure water at 4°C. Unfortunately there was a very small error and it was not until 1907 that it was detected. The "1889 Standard kilogramme" was discovered to have a mass of 1000.028 cc of pure water at 4°C and so it followed that a LITRE was 1000.028 cc. A decision was taken to leave the kilogramme as the "Standard" but to divide the LITRE into 1000 equal parts and to call this division by a new name the millilitre (ml).
From 1907 millilitres were used as the standard unit of liquid and volume measurement.
So 1 millilitre then equalled 1.000028 cc and 1 cc equalled 0.999972 ml.
Accordingly 1 millilitre of pure water at 4°C had a mass of 1 gramme
Apr 21 04, 4:32 PM
sequoianoir
In 1964 the General Conference of Weights and Measurements re-defined the LITRE as a true measurement of volume and so equal to 1000 centimetres cubed (cm3 or cc). This changed the specification of the litre, by the fact that its new definition is directly related to the metre as a measurement of volume and no longer to the kilogramme.
However, the millilitre remained as per the original specification and the ml calibration of scientific vessels used in very accurate analytical work is not 1/1000th of a litre where a litre = 1000cc, but where 1ml of pure water at 4°C has a mass of 1 gramme.
So 1ml does not equal 1cc
Apr 21 04, 4:33 PM
Sorry ... cannot be bothered with reading all that. Basically the take home message is where I left it with 'O' Level physics where there is an "essential" difference but no one can be bothered to define it simply!
