Whats that formula?

[hdtran]

1kg = 1L How simple is that?

1 kg is a measure of mass, referred to the platinum/iridium kg standard at BIPM in Paris, France.

1 L is a measure of volume, derived from the meter (1000 L in 1 cubic meter). The meter is referred to the speed of light in vacuum.

Conveniently, the density of pure water happens to be very close to 1000 kg/(m^3).

If I'm at higher altitude (say Denver, CO), and I heat my water to 90 C, then 1 L of water is not = 1 kg.

8)

 

[Anonymous]

And you'd STILL need to convert it to GALLONS!

Heavy...

 

[hdtran]

And you'd STILL need to convert it to GALLONS!

Heavy...

Since we're working with aquaria, wouldn't it make more sense to use the GILL as a unit of volume?

1 gill is equal to about 7.22 cubic inches in US customary units, and about 8.67 cubic inches in Imperial units.

(How many gills does that Imperator angelfish need to be happy?)

 

[Anonymous]

JESUS LORD PEOPLE...is anyone here good at math?

 

[Anonymous]

Oh, most definitely, that would NOT be me. My boyfriend, however, has a freakin' minor in math. He comes in quite handy.

 

[kim]

The really funny thing is that while some insist on clinging to pints and gallons, their governments quietly abolished them about 20 years ago and replaced everything with the metric system. As noted above, one inch equals 2.54 centimetres.

That exactness isn't a co-incidence....that's how the inch is defined. The inch doesn't exist except as a multiple of centimetres. Why people insist on measuring stuff in multiples of 2.54 cm is truly weird.



kim

 

[Anonymous]

Indeed, as, according to you lot, is driving on the right side of the road. Of course, I'm sure you understand that, even though most USAnians no longer remember why we got this way, we will hold steadfastly onto anything that is contrary to almost all that is English.

 

[kim]

Of course, I'm sure you understand that, even though most USAnians no longer remember why we got this way, we will hold steadfastly onto anything that is contrary to almost all that is English.

Fair enough. A little rebellion against our wise and loving parents is perfectly natural. The feeling will pass. :wink:

But don't forget that the metric system is actually French.

And believe me, a lot of my fellow countrymen (and ladies) find that a rather difficult pill to swallow !



kim

 

[hdtran]

The really funny thing is that while some insist on clinging to pints and gallons, their governments quietly abolished them about 20 years ago and replaced everything with the metric system. As noted above, one inch equals 2.54 centimetres.

That exactness isn't a co-incidence....that's how the inch is defined. The inch doesn't exist except as a multiple of centimetres. Why people insist on measuring stuff in multiples of 2.54 cm is truly weird.



kim

More than 20 years ago, more like 1893 when the US adopted the meter, kg, etc. as fundamental standards, from which inch, lb, etc. are derived.

There is a "unit" now out of favor, called the "metric inch" which is exactly 25 mm. It was the vogue for a while with machinists.

 

[kim]

Wow ! Earlier than I thought...

It is strange....I am no spring chicken....I am in my 40's (eek !) but at school (so 60's, 70's) everything was metric. Only recently have shops been obliged (in the UK) to quote metric measures (they may also, of course, give imperial equivalents for convenience), but outside the sciences and the trades, everyone uses pints and feet !

Even people half my age. They don't get it from school.... How many gallons is your tank ?

kim

 

[hdtran]

Wow ! Earlier than I thought...

It is strange....I am no spring chicken....I am in my 40's (eek !) but at school (so 60's, 70's) everything was metric. Only recently have shops been obliged (in the UK) to quote metric measures (they may also, of course, give imperial equivalents for convenience), but outside the sciences and the trades, everyone uses pints and feet !

Even people half my age. They don't get it from school.... How many gallons is your tank ?

kim

About 3840 gills (US) (60x18x26 inch, more or less)

 

[Mihai]

Actually, 1 liter of water = 1kg.

Regarding Air Canada, let me tell you a much better one: the previous NASA Mars mission (between the Pathfinder and the ones that currently have landers on Mars - Opportunity and Spirit) missed the landing because some of the software written by the guys in UK was using Imperial units (while NASA was using metric). I find this even more incredible than the Air Canda guys; after all the NASA guys are supposed to be "rocket scientists"

Mihai

 

[hdtran]

Mihai,

Don't want to rag on you, but I'm a metrologist and need to correct the liter/kg. 1 liter of water is absolutely not defined as being = 1 kg of mass. Way back in the 1790's, the French wanted to rationalize measurements (good thinking); they decided to define the kg in terms of volume of water. That has gone out since the mid 1800's. There is too much variability based on pressure, temperature, dissolved gases, and other impurities (not to mention surface tension effects or isotope composition) to be able to realize a kg from water to much better than 1 part in 1000. The kg is defined as a platinum iridium block hiding in a vault outside of Paris. The liter is 1/1000 of a cubic meter; the meter is the distance traveled by light in vacuum for a very small fraction of a second. The second is defined in terms of the radiation frequency of (I think) a Cesium isotope. Being able to specify mass based on a physical constant, as opposed to an artifact, is one of the remaining 'grand challenges' in metrology.

Yes, the NASA Mars orbiter/lander which burned up in the Mars atmosphere. Hate to say this, but all the blame comes to the US. Can't blame anybody in the UK for this. It was a US contractor (Lockheed Martin) providing customary US english units (the Aerospace industry is full of this) to NASA/JPL (which had specified SI) for the engine impulse.

Hy

 

[romunov]

1L of salt water weighs more than destilled liter. .)

 

[Anonymous]

Nerds

FWIW, a "pint" is no longer 16 oz, at least in bars. We order what's labeled "Bar Pint Glasses" at my job, and they are 14 oz. Standard practice at bars all over the US apparently, you get a 14 or 15 oz. pour of beer. Cheap B***ards!

 

[Arch01]

FWIW, a "pint" is no longer 16 oz, at least in bars. We order what's labeled "Bar Pint Glasses" at my job, and they are 14 oz. Standard practice at bars all over the US apparently, you get a 14 or 15 oz. pour of beer. Cheap B***ards

That's just not right!

Alex
_________________
Mercedes Benz 500E

 

[Mihai]

Hdtran,

I stand corrected .

My point was that 1 liter is not equal to 1kg unless you specify what you put into that liter volume. And I think that pure water comes pretty close (to many decimals under "normal" room temperature conditions + preasure).

Thanks for the lesson, I know that many of the normal measures are weirdly defined (platinum iridum block!?). I think that the second is just as weird (some huge number times the resonance frequence of the cessium atom!?).

Besides, I'm an engineer, and in our bussines if you got the results within 10% is good, 1% is outstanding . I guess that this just doesn't cut it for metrologists .

All the best,
Mihai

 

[hdtran]

Mihai:

Besides, I'm an engineer, and in our bussines if you got the results within 10% is good, 1% is outstanding . I guess that this just doesn't cut it for metrologists .

Hey, we metrologists is engineers too! 8) Some things are difficult to measure, and 10% is good (economic modeling); others, folks have figured out to 1 part in a billion relatively easily (measuring 1 meter).

The original question was how many (presumably US) gallons to the cubic inch, he (DLART89, I think) was not 100% assured of the answer given.

 

[Anonymous]

<sm waves her hand> Silly question here!

I thought you'd simply misspelled meteorologist, but you both consistently call "it" metrologist. What's a metrologist? Does it have anything to do with a "metrosexual"? If so, how? If not, why are they called metrosexuals? Do you study metros?

 

[hdtran]

Metrology:
(cut-and-pasted from webster's)

Main Entry: me·trol·o·gy
Pronunciation: me-'trä-l&-jE
Function: noun
Etymology: French métrologie, from Greek metrologia theory of ratios, from metron measure -- more at MEASURE
1 : the science of weights and measures or of measurement
2 : a system of weights and measures

A metrologist is a scientist or engineer specializing in measurements. You can subspecialize in dimensional metrology, electrical metrology, etc.