17 Apr 05
Originally posted by AThousandYoungThat is its value. Are you going to tell me cubic decimeters is also a metric unit?
Did you notice how 1 L = 1 dm^3 on that page? This can be mathematically manipulated via standard metric dimensional analysis to give 1 mL = 1 cm^3.
mL aren't there either...does that mean they shouldn't be used?
As for ml not being there - milli is there, abbreviated "m". And liter - abbreviated "L" or 'l" is there. And even my crack-addled brain can put milli and liter together to make ml. Standard unit, standard prefix. And that is why cc is not a metric unit.
17 Apr 05
3 edits
Originally posted by steerpikedo you have a problem that these units:
That is its value. Are you going to tell me cubic decimeters is also a metric unit?
As for ml not being there - milli is there, abbreviated "m". And liter - abbreviated "L" or 'l" is there. And even my crack-addled brain can put ...[text shortened]... rd unit, standard prefix. And that is why cc is not a metric unit.
Quantity Unit Symbol
length meter m
mass kilogram kg
time second s
electric current ampere A
thermodynamic temperature kelvin K
amount of substance mole mol
luminous intensity candela cd
--------------------------------------------------------------------------------
can be prefixed by any of these prefixes:
SI prefixes:
Prefix Symbol Multiplication factor
yotta Y 1024
zetta Z 1021
exa E 1018
peta P 1015
tera T 1012
giga G 1 000 000 000 109
mega M 1 000 000 106
kilo k 1000 103
hecto h 100 102
deka da 10 101
deci d 0.1 10-1
centi c 0.01 10-2
milli m 0.001 10-3
micro µ 0.000 001 10-6
nano n 0.000 000 001 10-9
pico p 10-12
femto f 10-15
atto a 10-18
zepto z 10-21
yocto y 10-24
the beauty of metric system is the standardisation of the use of prefixes for all quantities.
and later in the diagram it shows that volume is in cubic metres?
sure it does suggest that litre is an unecessary unit ... that is the purpose of this whole table ... they are all superfluous units simply used in addition to standard si for everyday convenience:
Quantity Unit Symbol Value in SI units
time minute min 1 min = 60 s
hour h 1 h = 60 min = 3600 s
day d 1 d = 24 h = 86 400 s
week, month, etc.
plane angle degree* ° 1° = (pi/180) rad
minute* ' 1' = (1/60)° = pi/10 800) rad
second* " 1" = (1/60)' = (pi/648 000) rad
revolution, turn r 1 r = 2 pi rad
area hectare ha 1 ha = 1 hm2 = 104 m2
volume liter** L, l 1 L = 1 dm3 = 10-3 m3
mass metric ton or tonne*** t 1 t = 103 kg
17 Apr 05
Originally posted by flexmoreLitre is unnecessay. The SI system was planned but some of the units lacked usability - which is why units like litre, cm and hectare are used.
do you have a problem that these units:
Quantity Unit Symbol
length meter m
mass kilogram kg
time second s
electric current ampere A
thermodynamic temperature kelvin K
amount of substance mole mol
luminous intensity candela cd
--------------------------------------------------------------------------------
can be prefixed by any of ...[text shortened]... s that volume is in cubic metres?
sure it does suggest that litre is an unecessary unit ...
And the metrication of time was a failure - we are left with the base 60 system devised by Iraqis.
17 Apr 05
4 edits
Originally posted by steerpikethere are 86400 seconds per day 🙁
Litre is unnecessay. The SI system was planned but some of the units lacked usability - which is why units like litre, cm and hectare are used.
And the metrication of time was a failure - we are left with the base 60 system devised by Iraqis.
a day is an obvious important (almost) unchangeable constant in our lives.
i think a second should be redefined as one 100000th of a day, and day be used as the base.
unfortunately the years do not cooperate well with the days ... but that is life and reality ... the si system has unnecesarily perpetuated a superfluous unit in our lives.
the old minute would be replaced by a milliday,
a week would be a Mega second, or a centiday - and weekends would be 3 days long 😀
thats my deka centi dollar's worth anyway 😉
17 Apr 05
Originally posted by royalchickenYeah, there seem certain Imperial units we don't seem to be able to let go of, the mile being one. And I'd consider myself a relatively rational person, but I could still never countenance measuring beer in anything other than pints. If only because glasses would move to half litres instead, which would be smaller...
As an outsider, the system seems even sillier in Britain, where they seem to have chosen at random which realms of life were to be penetrated by the metric system. However, it makes very little difference practically, because from context one learns to say, for example, that they used 4 litres of fuel to drive 30 miles in a vehicle 5 metres long.
Rich.
17 Apr 05
Originally posted by flexmoreDays are not constant in length, so they are not a good base unit of measurement. A second is far more constant.
there are 86400 seconds per day 🙁
a day is an obvious important (almost) unchangeable constant in our lives.
i think a second should be redefined as one 100000th of a day, and day be used as the base.
unfortunately the years do not cooperate well with the days ... but that is life and reality ... the si system has unnecesarily perpetuated a superfluou ...[text shortened]... centiday - and weekends would be 3 days long 😀
thats my deka centi dollar's worth anyway 😉
17 Apr 05
Originally posted by steerpikeThis is a pointless discussion. It comes down to the precise definition of "metric unit" I guess.
That is its value. Are you going to tell me cubic decimeters is also a metric unit?
As for ml not being there - milli is there, abbreviated "m". And liter - abbreviated "L" or 'l" is there. And even my crack-addled brain can put milli and liter together to make ml. Standard unit, standard prefix. And that is why cc is not a metric unit.
What's with you claiming cm are not acceptable metric units of measurement but mL are? That's totally ridiculous.
17 Apr 05
I wonder if any of the Americans here who claim that America should stick with the imperial system know that America signed the Treaty of the Metre in 1875 which defined the international standards of measurement as the metric system.
Also the reason mL is more accepted than cm is because SI units only use the prefixes associated with powers of 3 (milli is 10^-3, kilo is 10^3 however centi is 10^-2). While cm may be used in many applications their use is frowned upon in scientific circles and plans and the like will invariably use mm or m.
18 Apr 05
Originally posted by RingtailhunterEven if the USA is mainly imperial, metric units are definately required if you are to study scientific subjects. All of physics and chemistry and perhaps a few other sciences too are based on things called SI units. Ie seconds metres newtons etc,. All of these are interlinked and quite easy to use, but if you try using feet pouns and the likes, it just doesn't add up too easy. I can understand what you are saying, i live in England and it's all mixed up over here. Someone can ask you the temperature and you cn say ' its 25 degrees centigrade and they don't undestand so then you have to start working it all out. I blame the French myself.
The metric system and schools in the United States.
My daughter came to me the other night with a math problem involving the metric system....why? Why do they keep cramming that system down our throats if we are never going to use it?
I have yet to roll open a blue print of a building and have it be in metric (although it would make life a lot ...[text shortened]... k on a foreign car (or try to take off every other part on a ford),it is totally useless.
RTh
18 Apr 05
Originally posted by jimslyp69You know. I want to blame the french too!
Even if the USA is mainly imperial, metric units are definately required if you are to study scientific subjects. All of physics and chemistry and perhaps a few other sciences too are based on things called SI units. Ie seconds metres newtons etc,. All of these are interlinked and quite easy to use, but if you try using feet pouns and the likes, it just do ...[text shortened]... d they don't undestand so then you have to start working it all out. I blame the French myself.
RTh
18 Apr 05
Originally posted by jimslyp69centrigade isn't an SI unit. The SI unit for temperature is Kelvin (K). Add 273.15 to all values.
Even if the USA is mainly imperial, metric units are definately required if you are to study scientific subjects. All of physics and chemistry and perhaps a few other sciences too are based on things called SI units. Ie seconds metres newtons etc,. All of these are interlinked and quite easy to use, but if you try using feet pouns and the likes, it just do ...[text shortened]... d they don't undestand so then you have to start working it all out. I blame the French myself.
18 Apr 05
1 edit
Originally posted by XanthosNZSI units only use the prefixes associated with powers of 3 (milli is 10^-3, kilo is 10^3 however centi is 10^-2)
I wonder if any of the Americans here who claim that America should stick with the imperial system know that America signed the Treaty of the Metre in 1875 which defined the international standards of measurement as the metric system.
...[text shortened]... ntific circles and plans and the like will invariably use mm or m.
That's not what the website steerpike gave the address to says. I have a degree in biochemistry; I don't recall anyone ever saying SI prefixes had to be in powers of 3, either. I think you made that up.