Are you still imperial?

[Walter]

I'm confused. I was under the impression metric was logical. If it's logical, why does 1 cubic centimeter equal 1 mililiter? Why does 1 cc or ml of water weigh a whole gram and not 1/100 or 1/1000 of a gram? This was to make it easy? It's easy to slip a decimal. At least with the English system, I know I'll have to covert from one to the other, with metric, they lull you to sleep and then try to sneak in the illogical conversions.

 

[Rick Murchison]

In the real world one will run into both systems, as well as others. For example, my 1985 Chevy Blazer is mostly manufactured using imperial measurements - the engine has all imperial nuts & bolts & internal components, but is labeled a 2.8 liter engine, a trendy way to say 98 cubic inches. On the body of the Blazer the most common fastener is the 10mm hex head bolt - so I have to keep both metric and imperial tools available. The same is true of scuba gear. If you ever wondered why your 4mm allen wrench seems a little loose and prone to stripping in your port plugs, that's because they're actually 5/32 inch allen heads.
The yoke inserts for my 200 bar DIN valves use a 7mm allen. As for "making sense" from a physics or computing view a 10 base system is just as nonsensical as any other, and some sort of base 2 system would be better (in this area the imperial measurements of 1/2, 1/4, 1/8 etc. typically used for measurements less than an inch make more sense than the metric system). We only use a 10 base system because most of us have ten digits on our two hands.
The two most common universal measurements in use today are the barrel (of oil) and the US dollar.
As for me, I think it's worthwhile to be able to deal in the local system, whether that's kilos or pounds, furlongs or kilometers, dollars or pesos.
Rick

 

[mddolson]

Walter Bubbled" I'm confused. I was under the impression metric was logical. If it's logical, why does 1 cubic centimeter equal 1 mililiter? Why does 1 cc or ml of water weigh a whole gram and not 1/100 or 1/1000 of a gram?"

The confusion is when we mix linear units and volumetric meaures. Like mixing cubic inches and ounces of water, or cubic ft and gallons.

Linear units are easy because they are based on units of 10, 100 1000.

For distance
Meter =(about 39.4 inches), (1/10) decimeter, (1/100) centimeter and (1/1000) millimeter (the decimeter is 1/10 of a meter and not very usefull so we use 10 centimeters) for fine measurement we use millimeters 1 mm = 0.0397 inches or about 0.04"

For mass and volume we use water as the base.

1 Litre of water has a mass of 1000 grams = 1 Kg (Kilogram) 2.2 lbs)
1 mililiter (1/1000 litre) water = 1 gram mass

the vol. equivalent measure to get 1 milli-litre is 1 cubic centimeter. or a cc.

Hope this helps

Mike D

 

[Walter]

mddolson,

I know this, I was being sarcastic, pointing out that the stsyem is not as logical as many claim.

Logic would change those proportions.

1 Liter of water has a mass of 1000 grams = 1 Kg (Kilogram) 1 mililiter (1/1000 liter) water = 1 gram mass

Logically one would come up with a better system. 1 Liter of water should have a mass of 1 gram 1 mililiter (1/1000 litre) water should = 1 miligram mass. Additionally 1 cubic meter should equal 1 liter.

"For mass and volume we use water as the base."

Not so. Volume is based on the linear measurments, not water. Mass was once based on water, but that system was abandoned.

 

[Epinephelus]

I think Rick hit the nail on the head... be able to operate in whatever system is used locally....
Una mas cervesa, por favor.... frio y mas fina...
E. itajara

 

[O-ring]

...given that Liberians are known for being the most accurate people in the world I think everyone should switch back to Imperial and stop confusing the rest of the world..

 

[Arnaud]

Actually, I was going to second Epinephelus's proposition. Let's all switch to a bier-based system. Who wants to dive a 12-pack?

 

[Liquid]

Walter once bubbled...
I'm confused. I was under the impression metric was logical. If it's logical, why does 1 cubic centimeter equal 1 mililiter? Why does 1 cc or ml of water weigh a whole gram and not 1/100 or 1/1000 of a gram? This was to make it easy? It's easy to slip a decimal. At least with the English system, I know I'll have to covert from one to the other, with metric, they lull you to sleep and then try to sneak in the illogical conversions.

Walter- when you increase dimension, you also increase the amount of "smaller measurements" inside a bigger one by the same proportion:
thus- 1meter=100 cm, but - 1 meter^2(squere)=100^2 =10000 squared centimeter=1000^2 square MM. Now let's see you do it with square inches and square yards. much more complicated.

When going 3 dimensional- 1 cu M- 100^3 cu cm and so on. Let's see it with inches and miles. Get the point?

A liter equals 1000 CM^3, BY DEFINITION, in order to create a more comfotable measurement for volumes, since the regular ones became so far.

As for the water issue- 10M is the depth of water needed to increase pressure by 1 atmosphere. The 1 gram for one cc is a deriviative, which, actualy, shouldn't be used, becouse it is only correct for pure H2O in certain conditions, or in other words- close to never. It's just a popular mistake.

And for something I just found out- The sizes of the imperial measures, by definition in law, are deriviated from metric measures. Iv'e just seen the law definition a galon. It has a lot of metric in it. The reason is, that today, metric definitions are much more pecise- 1 M equals so and so wavelengths of Cs when going from one energy level to the next (and dot expect me t remeber the whole thing).

 

[The Iceni]

Rick Murchison once bubbled...

A mil has absolutely nothing to do with the metric system. It is, rather, a measure of offset relative to distance - "One mil" represents one foot displacement at 1000 feet, and is the standard used to set gunsights and measure ballistic dispersion & such. A dumb bomb, for example, has a ballistic dispersion of about four mils, so if dropped in a 45 degree dive from 4,000' could be expected to hit within an ellipse measuring about 56' wide and 96' long with the aim point in the center.
And there are 2000 X pi mils in a circle.
Rick

Thanks Rick,

No one ever explained that to me. It certainly makes for easier calculations. The nearest I got to being an artilleryman was my Sergeant Major's offer of letting me take a mortar base plate on a battalion jump. I reluctantly declined the offer of 45 lbs (or was it 45 kgs?) of additional weight!!!

Pi x 2000 = 6,284 mils in a full circle. 90 degrees = 1,571 mils. ( I much prefer degrees and minutes of arc for navigation!)

I am not sure decimals are due to us having ten fingers, I think it is more to do with moving decimal points and the mathematical powers of the magical number "10".

Is this thread about The Metric system or a metric system? I concur with mdonaldson. The Metric system is based on the Metre as the unit oflength and all other measures of length follow from it; in divisions of ten, 100 or 1,000 with appropriate prefixes. Because the area of an object is determined by the squared power of its linear dimensions, and volume by the cube power of its linear dimensions the prefixes are not interchangeable from length to area to volume.

In the scientific world units are normally restricted to the power of 10^+-3 (that is one thousand units or a thousandth of a unit.) It is far easier to understand and to work with 2.5 millimetres than 0.0025, 2.5 x10^-3 or 2.5/1000 of a metre, which are all the same length!

As for microscopy, I do not know if there is a term for a millionth of a Metre (1x10^-6) but if I remember correctly one Micron is 1x10^-9, while an Angstrom is a tenth of a Micron; 1 x 10 ^-10 Metres.

For the same reason (simplicity in the use of those particular units alone) we tend to use the same prefixes for volume, at least. A decilitre is 1/10 of a litre and a millilitre is 1/1000 of a litre. Blood cell volumes are measuerd in fentilitres.

A decimeter (pronounced "desimeter") is a tenth of a metre and a decameter (dekametre) would be 10 metres. A centimetre is 1/100 of a metre (and 100 meters would I suspect be a centametre but this a term that I have never used.) A millimetre is 1/1000 of a metre and 1000 meters is a mil . . . a kilometre!!!!

A kilogram is 1,000 grams. A litre is 1,000 mls so if one ml. weighs 1 gram a litre weighs a kilogram.

What about bytes, kilobytes, megabites and gigabites? There are 1,028 bytes in a kilobyte becuse this is a binary, not a decimal system.

All of which proves you should only use the system with which you are familiar or you WILL make mistakes

 

[slowdiver]

Metric was a little easier in school math, but life in the U.S. is imperial most of the time.