Systeme Internationale Definitions

[uncle tom]

Split from Travel tips for busy port drinkers due to the sort of error that has Jumbo Jets landing on water - Admin

60ml - isn't cc the same as cl?

No. One cc (cubic centimetre) = 1mL or 0.1cL

One litre = 10dL (never used)
- or 100cL (only used for wines and spirits)
- or 1000mL - also known as cc

(there is a technical difference between cc and mL, but only a pedantic nerd would worry about it..)

We should stick to pints (British ones, that is; not those short measured American efforts.. )

60mL is just over 1/10 of a British pint, or just over 1/8 of an American one.

Tom

"O plump head-waiter at The Cock, To which I most resort, How goes the time? 'Tis five o'clock. Go fetch a pint of port" - Tennyson

[Glenn E.]

(there is a technical difference between cc and mL, but only a pedantic nerd would worry about it..)

Ooh, really? What is it?

Oops, did I just label myself?

[KillerB]

(there is a technical difference between cc and mL, but only a pedantic nerd would worry about it..)

Ooh, really? What is it?

Oops, did I just label myself?

Pedantic nerd here. Come on Tom, is it just as dull as one being based on length units and the other on volume units?

[g-man]

(there is a technical difference between cc and mL, but only a pedantic nerd would worry about it..)

Ooh, really? What is it?

Oops, did I just label myself?

Pedantic nerd here. Come on Tom, is it just as dull as one being based on length units and the other on volume units?

even worse,

one has 2 "c"s and the other has a "m" and "l"!

[uncle tom]

Pedantic nerd here. Come on Tom, is it just as dull as one being based on length units and the other on volume units?

OK.. yawn.. It does actually depend on the defintion of litre used. My schooling taught me that a litre was one Kg of pure water at 4C and 760mm mercury pressure, which is very slighly more than a cubic decimetre. When the temperature or pressure changes, so does the volume of the water (slightly), but it is still a litre. It follows that a litre is not always quite the same size.

Bringing myself up-to-date, it appears that the favoured definition today defines a litre as simply a cubic decimetre; by which defintion, a mL and cc would be exactly the same.

Tom

[KillerB]

My problem with that is that I was taught that a litre was defined based on the lengths and the kilogram was defined based on the mass of 1 litre of water at 0C, not the other way around. The metre being the core measurement and everything else derived from it. The trouble with SI is that after that it decided to get technical and buggered itself up in definitions, so it's now determined by a lump of metal.

[uncle tom]

..And the metre was supposed to be a 1/10,000,000 of a quarter of the world's circumference, except they didn't measure that very well, and later discovered that the world is actually slightly pear-shaped..


..says it all, really..

Tom

[JacobH]

My problem with that is that I was taught that a litre was defined based on the lengths and the kilogram was defined based on the mass of 1 litre of water at 0C, not the other way around. The metre being the core measurement and everything else derived from it. The trouble with SI is that after that it decided to get technical and buggered itself up in definitions, so it's now determined by a lump of metal.

I thought the kilogram had always been defined by the International Prototype:



with current efforts being aimed at producing a perfectly round ball of Silicon weighing the same as the International Prototype so that they can define a kg as the mass (it is mass, not weight?) of a certain number of atoms of Silicon.

That said, the metre and second definitions are probably no more sensible than having a lump of metal:

The metre is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second.

The second is the duration of 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.

[Alex Bridgeman]

The metre is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second.

But doesn't that depend on the gravity field through which the light is passing?

Methinks we may have wondered off topic a little. Should we consign everything from Derek's original post down to meaningless drivel?

[JacobH]

The metre is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second.

But doesn't that depend on the gravity field through which the light is passing?

Pass (but perhaps c.f.).

Methinks we may have wondered off topic a little. Should we consign everything from Derek's original post down to meaningless drivel?

That may make sense...

[g-man]

with current efforts being aimed at producing a perfectly round ball of Silicon weighing the same as the International Prototype so that they can define a kg as the mass (it is mass, not weight?) of a certain number of atoms of Silicon.

it's mass,

weight = the mass * the gravitational acceleration of your environment.

[jdaw1]

The metre being the core measurement and everything else derived from it.

I saw this and thought ‘whoops’. Then I saw

The metre is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second.

The second is the duration of 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.

JacobH politely declined to remark explicitly that the second is the core measurement.

[KillerB]

The metre being the core measurement and everything else derived from it.

I saw this and thought ‘whoops’. Then I saw

The metre is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second.

The second is the duration of 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.

JacobH politely declined to remark explicitly that the second is the core measurement.

Busted - of course it is.

I was thinking of those measurements subsequently defined as the second was already in existence. Everything being determined by Mass, Length and Time. Should have remembered the Time thing - I was having a strictly Pagan moment where Time was a concept that didn't exist. As you were.

[Alex Bridgeman]

So, to summarise, Derek will now be trying to fit his work shirt and a bottle of port into something the size of a caesium atom and has a fraction of a second to achieve this act, or as much time as he wants if he does it in the dark where there is no light to see by.

Have I understood correctly?

[g-man]

So, to summarise, Derek will now be trying to fit his work shirt and a bottle of port into something the size of a caesium atom and has a fraction of a second to achieve this act, or as much time as he wants if he does it in the dark where there is no light to see by.

Have I understood correctly?

No, no, no

Derek will now be trying to fit his work shirt and a bottle of port into a ball of silicon before the lights come on hopefully with no after affects of cesium radiation.

[Glenn E.]

So, to summarise, Derek will now be trying to fit his work shirt and a bottle of port into something the size of a caesium atom and has a fraction of a second to achieve this act, or as much time as he wants if he does it in the dark where there is no light to see by.

Have I understood correctly?

No, no, no

Derek will now be trying to fit his work shirt and a bottle of port into a ball of silicon before the lights come on hopefully with no after affects of cesium radiation.

You forgot the vacuum. He has to vacuum his shirt first.