CGS Units- The Other Metric System

How I agree so much that the S.I. system allows people - in my case students - to check thier working equations by ensuring that the answer is in the units they expect.

I think however, that c.g.s is an unnecessary diversion and staying with a true S.I. system would help us all.

However, two ideas do come to mind.

1) Mass - can we please invent a new name for the kilogram? This would then allow us to have a properly consistent mass derivation as in Millimetre, Centimetre and Kilometre.

2) Can someone please explain how we have all agreed to to a time and angle system working on a base 60 - I suspect that this is traceable back to the Greek number system which used base 60 - but oh if we used base 60 now we would all have such short phone numbers, but the phone keypads would be so much larger.

Regards

Hugh Mattos - Chartered Engineer

You Wrote: "2) Can someone please explain how we have all agreed to to a time and angle system working on a base 60 - I suspect that this is traceable back to the Greek number system which used base 60 - but oh if we used base 60 now we would all have such short phone numbers, but the phone keypads would be so much larger."

As you suspected, the reason we use a base 60 system for time and angles is historical. A base 60 system is easier for calculations involving its factors, 1,2,3,4,5,6,10,12,15,20,30,60 (decimals are easily avoided). The truth is though that it comes from astronomy, since multiples and factors of 60 naturally occur in nature (lunar cycle of 30 days, year of ~360 days). Base 10 systems originate from the fact that we use our fingers to count, and we have 10 of them. That's it. In our typlically anthrocentric way, we've created myth that base 10 is superior to other counting systems, but the truth is it isn't. It's just the one we are most familiar and comfortable with.

Actually the Greeks used a base 10 number system. It was the Babylonians that used the base 60 number system. (Babylonian number system) Of course, the Babylonians didn't invent it because the Sumerians used it long before them (Sumerian number system)

It's interesting to note that there was an attempt to implement the idea of metric time (though it was called "decimal time") during the French Revolution , but it failed miserably. (Some History on Decimal Time)

Your response is rrihght on the money! For a concise vernacular treatment of this subject : author - Daniel Borstein; book -The Discoverers ; chapter - TIME

Now, now Roger! You've still got angular velocity in 1/s. Should be in radians/s as in SI units.

Also you give torque - dyn·cm - g·cm²/s. Typo, I expect, but it should be g·cm²/s².

Cheers.....Codey

Hi Codemaster,

Ah yes, the radian. The great thing about this blog is it forces me to examine details that I otherwise might miss (in this case by you bringing it to my attention). Although what I have written in the past, that angles are unitless, is not technically incorrect, it does leave out too much of the story. Having given it way too much research and thought after my discussions with you and Fyz, I've come to agree with you that radian belongs on that list. However, I don't think just giving radians as the units for an angle tells the whole story either, so I've decided to go with "Radian (rad) - m/m - dimensionless" as the way to describe the units for angles in the SI system (and CGS). Take a look above and also in Units Part I - Mechanical where I've made the changes.

You Wrote: "Also you give torque - dyn·cm - g·cm²/s. Typo, I expect, but it should be g·cm²/s²."

You're correct, I've made the correction.

I really appreciate all attempts for supporting the use of the SI-System for metrics. Grown up in Germanys previous system based on kiloponds, calories, etc. it was an awful pain not going lost between all the conversion numbers between the metrics (e.g. mechanic to thermal). It was my impression, the physicans were interested in protecting their knowledge by making understanding and use of natural laws difficult for everyone with all the conversions. I know, this was not the reason.

Anyhow - with Introduction of the SI-System I could unload my brain from conversion knowledge and concentrate on understanding. So simple now to combine mechanical, thermal, electrical and other effects in one model. Checking the units will tell you quickly if the equations properly transformed. Or otherwise: the wanted result in units already will give you an idea about the required equations/effects. I never going back to the old systems for sure. I beg pardon to all Americans preferring their Imperial System, but this system is ignoring the work of all famous scientists from Newton to Einstein - it is representing a farmers socienty sufficiently, but is a burden on international business relationships and is wasting the brain of scientists and technicians. Formerly president Reagan brought the ingnorance to a populistic point when saying, the cooking results won't be better if housewifes would meter in kg and liters instead in gallons (pints) and pound - so, why to stress them with changes ...

SI is based on m, kg, s, A, K, mol and cd. All other units are "derived" units from these basics. Personally I highly disuade from any attempt promoting changes to the SI definitions, as far as changes are not required from better understandings of the nature. Where to see the advantage for your CGS proposal? What does it help to change the base for mass from kg to g - and at same time changing base for distance from m to cm? Except for changing the exponent for some numbers a CGS would spend confusion about definitions.

In SI you are free using derived units and (defined) multiplication factors like kilo, milli, centi, Mega ...

In case you feeling is, the numbers important for your branch or business are not handy, you can use those factors to make them handy. But don't promote a new system.

regards, Albert

Albert, I agree with most of what you say - but what about the kilogram - it is an illogical unit in the S.I system as its derived units are confusing.

Do you really want to use the millikilogram (gram) and the kilokilogram (tonne) as common usage terms.

Let us come up with a new name for the kilogram and then all will be simpler.

Hugh Mattos

Hugh - I can see the logic of what you're saying, it seems odd to have a basic unit which appears to be derived as it has a kilo factor. But in practice it works OK and I don't think a change is anywhere near justifiable. But if you can persuade the scientific etc community, may I suggest a name - SIM for S.I. mass unit?

Cheers......Codey

SIM is a possibility. The kilogram was originally a barye, meaning heavy. Gram is a Greek word meaning small weight, and a gram really is small. The gram was originally intended as the base unit, but turned out to be too light to really be a good base unit. The kilogram is of a reasonable size to be a base unit.

Albert-

For what it's worth, the CGS system was in use quite a while back, rather than being "introduced" recently: my first formal introduction to the metric system was in that form, back in the mid 1950's. My high school physics texts used it exclusively, as did my college ones (and I majored in Physics). It was some years later that I first worked in a situation where the normal basis was MKS. Even then, I'm not sure I had ever even heard of SI. It may well be that SI and MKS were in common use in Europe or elsewhere, but they were not universal. It took me some effort to break habits learned using CGS, but I can work either way, or in Imperial (because that's what was used exclusively, back when I was born and while I was growing up). I quite agree that the USA should have adopted a SYSTEM of measurement long since, instead of being one of three countries still using a hodgepodge / compilation / cluster___. It wastes time & brainpower - not only for scientists & engineers - causes unnecessary errors, leads to absurd situations for commodities such as dimensioned lumber, and costs everyone in the country actual money. Yet, I don't know of a single politician who supports changing . . .

I think that times may be a changing. Following two losses of expensive American space craft due to Metric / Imperial conversion errors, I think the engineering profession is at the forefront of the campaign to convert technical matters to S.I.. Once that is done, you have a chance to convert the rest of the society - based on my experience in the U.K. I suggest we need to accept that the changeover will take upwards of 50 years from now.

I proposse the "masso" name instead of "kilogramo" so the "gramo" could be "milimasso".

Be happy, it´s question to according names.

Jokes are common between coleagues.

In your footnote on Calorie, you say that 1000 calories is called a Calorie. If this is the case, what is a kilocalorie?

You Wrote: "In your footnote on Calorie, you say that 1000 calories is called a Calorie. If this is the case, what is a kilocalorie?"

The thing about calories (sometimes called gram calories) and Calories (sometimes called kilogram calories) is that they are usually used in different context. When kilocalorie is used, whether it actually means 1000 calories or 1000 Calories (1000000 calories) also depends on the context. If this seems extremely inefficient, well, that's what happens when everybody thinks they know whats best and there's no formal standard that forces them to conform.

Our standards organizations provide an invaluable service to us. Whether we agree with all their decisions or not, they prevent international science from devolving into regional or disciplinal dialects.

I don't think anyone would want a 100000 calorie pack as a snack, any more than a 140000 calorie drink, or a 2 000 000 calorie diet. These are the small calories, but the numbers would be alarming.