Kilogram Poses Weighty Problem

[BrandonL]

If several scientists get their way, a 2.2-pound hunk of metal -- the international prototype of the kilogram -- may soon be out of style.

Like its six basic-units-of-measurement siblings before it -- including the meter -- the kilogram may be moving toward a new definition based on a universal constant. The kilogram has long been understood to equal the mass of its prototype.

Work has been underway for about 25 years to switch the kilogram from being defined by a physical model to corresponding instead to a constant. A paper to be released Monday proposes redefining the unit via fixing the values of one of two well-known universal constants. The choices offered up are Avogadro's constant or Planck's constant; the former measures the amount of carbon-12 atoms in 0.012 kg of that element, while the latter is used to explain the sizes of quanta, which are tiny electromagnetic energy packets.

Link (http://wired.com/news/technology/0,1282,66727,00.html?tw=wn_tophead_1")

[Lazarus]

Does this mean I have to learn to use metric? ::) ::) ::)

[ponygurl]

I learned metric in grade 7(I think) . I still think in Imperial.
The only metric that makes 100% sense to me is speed.

[BrandonL]

Does this mean I have to learn to use metric? ::) ::) ::)
Well, you should learn it anyways...Realistically, it does make a lot more sense that our current system. It much more logically defined.

[BrandonL]

The only metric that makes 100% sense to me is speed.
Well, speed, weight, etc. are all defined by the same means: base 10. So, if one is easy, the rest should be as well.

[ponygurl]

Well, speed, weight, etc. are all defined by the same means: base 10. So, if one is easy, the rest should be as well.

Then quick.. fast as a flea.. tell me if you need a sweatr when it's 14C out. ;D

[ponygurl]

Then quick.. fast as a flea.. tell me if you need a sweatr when it's 14C out. ;D

Of course the correct answer is no man under 59 wears a "sweater". ;D

[BrandonL]

Then quick.. fast as a flea.. tell me if you need a sweatr when it's 14C out. ;D
Hell woman, I didn't say I could CONVERT with ease, just said that all the metric measurements (if that's what's used) are easy to convert to each other, or within their system! :P

[Lazarus]

Well, you should learn it anyways...Realistically, it does make a lot more sense that our current system. It much more logically defined.


What makes you think I really don't know it (did you read something to that effect on the internet)? ;)

[BrandonL]

What makes you think I really don't know it (did you read something to that effect on the internet)? ;)
I know you...you hate anything Euro-peon ;)

[jeny]

The metric system might make more mathmatical sense but to people who use the imperial system, the terms "cup" and "mile" and "foot" have more literal meaning.

[kathleen]

the terms "cup" and "mile" and "foot" have more literal meaning.


Not so great for the international trading industry or the scientific professions either.

If I am a businessman wanting to buy 1000 kilograms of grapes from you, I want to be certain I'm getting exactly 1000 kilograms.

[kathleen]

Work has been underway for about 25 years to switch the kilogram from being defined by a physical model to corresponding instead to a constant.

I think this is a good idea. :)

Maybe LaL can explain why.........can you LaL?

This is a test. ;)

[jeny]

Not so great for the international trading industry or the scientific professions either.

If I am a businessman wanting to buy 1000 kilograms of grapes from you, I want to be certain I'm getting exactly 1000 kilograms.


so? convert.

1 000 kilograms = 2 204.62262 pounds

[kathleen]

so? convert.

1 000 kilograms = 2 204.62262 pounds


The problem is that there is no international standard for the pound.

Neither is there a scientific one, for the obvious reasons.

[BrandonL]

Conversions cause many problems. Look at the Mars mission a few years back. The conversion was not exact enough from Imerial to metric, and the craft burned up on entry. One or the other.

While not saying that we should immediately switch to Metric-but if an entire planet can make the switch, what really is stopping us? Heck, the military doesn't even use Imperial...nor do scientists. Really, just the common folk, basic commerce, and car manufacturers do.

[Larry_Oldtimer]

Well, you should learn it anyways...Realistically, it does make a lot more sense that our current system. It much more logically defined.


So? How foolish to base everything on something called logic, rather than on usefullness.

It happens that thousandths of an inch are real handy for tolerances in machining for mechanical tolerance purposes. There are no metric equivalents which are as useful without some convoluted decimals. Millimeters are too large, and And when convoluted decimals are used, errors happen. :o

[BrandonL]

It happens that thousanths of an inch are real handy for tolerances in machining for mechanical tolerance purposes. There are no metric equivalents which are as useful without some convoluted decimals. Millimeters are too large, and And when convoluted decimals are used, errors happen. :o
Use a micro or a nanometer then. They follow on the exact stepping of the rest of the metric system.

[Larry_Oldtimer]

Use a micro or a nanometer then. They follow on the exact stepping of the rest of the metric system.


Once again, using those measurement units, hard to remember numbers. Been there, done that. ::) Oh, and I majored in physics in college . . . am very familiar with metric units and conversions.

[BrandonL]

Once again, using those measurement units, hard to remember numbers. Been there, done that. ::) Oh, and I majored in physics in college . . . am very familiar with metric units and conversions.
What do you mean? To convert from one to the other requires moving the decimal x number of places to the right or the left? You have 10 micrometers, or 10,000 nanometers.

As a side note-why are transistor spacings in CPUs measured in nanometers, and not thousands of an inch?

[Larry_Oldtimer]

The metric system might make more mathmatical sense but to people who use the imperial system, the terms "cup" and "mile" and "foot" have more literal meaning.


The point I was making, jeny. Useful, easy to remember units which have real meaning in ordinary life . . . and easy to see mentally. Sure, there are metric equivalents . . . but rather complex numbers, not easy to comprehend or remember. Only if you like long strings of numerical characters. ;)

[BrandonL]

Imperial is harder to convert. There is no "standard". A certain number of feet are in a mile. A different number of yards are in a mile. A quart is a certain number of cups, but a totally different number of tablespoons. Nothing is logical about it. With Imperial-you have to memorize all of the conversions. To convert from a certain weight, to another weight-you just move the decimal.

Exactly-what is a pound? What is it based on? What constant makes a pound? How is it determined?

[Larry_Oldtimer]

Imperial is harder to convert. There is no "standard". A certain number of feet are in a mile. A different number of yards are in a mile. A quart is a certain number of cups, but a totally different number of tablespoons. Nothing is logical about it. With Imperial-you have to memorize all of the conversions. To convert from a certain weight, to another weight-you just move the decimal.

Exactly-what is a pound? What is it based on? What constant makes a pound? How is it determined?


In this modern day of computers, who cares how difficult or easy it is? Geez . . . no problem. And who cares whether there is any natural constant either? Constant can be by definition just as well, and lots of measurement is based on exactly that . . . definition. What is more important is that the measurement system be based on what is useful, not on some natural constant. After all, the meter is based on the the distance of an imaginary line that began at the North Pole, ended at the equator (AKA a quadrant) and ran through Paris. This line is then divided into exactly ten million identical pieces. The length of one of these pieces is a meter (actually a metre, not exactly the same thing, but who cares anyway). Now talk about a non-constant, this is one. The earth is not static, so this is a piss poor way of determining a standard. It is also as artificial as any other base of measurement.

Any system of measurement should be acceptable to the scientific community, so long as it is definable and not changable (as the metre is). For the rest of us, including those of us with scientific training who are indulging in other than science, it should be based more on what we can get our minds around, so as to have practical meaning. The foot is useful, as a fair approximation can be had by merely looking at ones foot . . . for an adult male, won't be all that far off. Same as a pint . . . a lot easier to think about visually than 0.4731 litres . . . could always think a half litre, but damn, then it wouldn't be a pint, would it? Most of the reasons for uniformity in measurement systems have long since passed, as most of us don't do math on paper or in our heads anymore. As far as conversions, any physical scientists who can't deal with conversions between systems aren't all that competent in any event. ;)

[BrandonL]

The foot is useful, as a fair approximation can be had by merely looking at ones foot . . . for an adult male, won't be all that far off. Yeah, right. Sizes range from 7 to 20 on foot sizes. My foot is not 12 inches...or really close. Perhaps we should all switch to cubits? ::) Standards are the way to go. Changing the kg to a scientific constant could only lead to changing all the metric measurements to constants.
Same as a pint . . . a lot easier to think about visually than 0.4731 litres . . . could always think a half litre, but damn, then it wouldn't be a pint, would it?See, you are too locked up in thinking Imperial measurents. If you had lived your whole life with metric, a litre would be just as quantifiable as a pint. If you start off with litres, and want millilitres, it's far easier than converting Pints to say, tablespoons. FAR easier.
Most of the reasons for uniformity in measurement systems have long since passed, as most of us don't do math on paper or in our heads anymore. As far as conversions, any physical scientists who can't deal with conversions between systems aren't all that competent in any event. ;)
Well, you might want to talk to those PhD's at JPL that didn't convert enough to stop a Mars lander from entering the atmosphere wrong. Conversions should NEVER be done. Choose one measurement and stick with it.

[Larry_Oldtimer]

Brandon: Well, you might want to talk to those PhD's at JPL that didn't convert enough to stop a Mars lander from entering the atmosphere wrong. Conversions should NEVER be done. Choose one measurement and stick with it.

Well, damn, as I said as to competence. And you seem to forget that we in the US have many standards, based on English measurements . . . the 12 foot lane for freeways, milepost markers . . . spacing on 100 foot intervals for highway paddles . . . thicknesses of asphalt layers . . . pipe sizes . . . these are but a few relative to highway engineering which would require conversions. A complete list would be humungous. Moreover, all of our machines, scales and the like, which don't measure in metric system would have to be scrapped, along with all other tape measures and any other devices of measurement, and the cost would be tremendous . . . without benefit of any real value. If the scientists want to go to metric, so be it, but there are in reality no reasons why the rest of us should be forced to to no purpose. Whether I buy a pound or 0.4536 kg of meat makes no difference. And by the way, a kilogram is after all a measurement of mass, and a pound is a measurement of force, so one can't be converted to the other anyway. Spring scales can't in any case accurately measure mass, as gravitational forces aren't exactly the same every where on earth. But if you want to measure force in Newtons or dynes, be my guest, I'll stick to pounds, thank you. :o If you want to do the world a real favor, work on substituting units for the idiotic units used in angular measurement . . . 360 degress in a circle, each degree divided into 60 minutes and each minute divided into 60 seconds. A decimal compass would really be useful, and talk about avoiding conversion errors! :o

[BrandonL]

larry, what you seem to be missing is not that the Imperial system is "bad", but that the metric system is easier to convert from one measurement to the other. I have said that to go from feet to miles it's one number. Yards to miles it's another. Feet to yards, yet another. Tablespoons to gallons, several more. Inches to miles-you've got to convert not once, but multiple times. And, it's not as simple as moving a decimal place. it requires you to know exactly how many inchers are in a foot, then feet in a mile. They are an arbitrary measurement.

So, exactly what is a pound? Can i pick up a rock today and know that is a pound? Can I go down to the local creek bed and pick up exactly a pound of rocks? Fact is the pound is an arbitrary measurement. What these scientists are trying to do is base the kilogram on something that never changes.

[BrandonL]

If you want to do the world a real favor, work on substituting units for the idiotic units used in angular measurement . . . 360 degress in a circle, each degree divided into 60 minutes and each minute divided into 60 seconds. A decimal compass would really be useful, and talk about avoiding conversion errors! :o
There are decimal clocks and navigation devices. if you really want, I can give you links to decimal clocks that use either binary, or any other form of measurement in the metric system.

[jeny]

Inches to miles-you've got to convert not once, but multiple times.


Why? Converting is really easy in the computer age. Do a google, there are 63,360 inches in one mile. It's just one conversion??

[BrandonL]

Why? Converting is really easy in the computer age. Do a google, there are 63,360 inches in one mile. It's just one conversion??
Here's one you don't need to use a calculator or Google for: how many meters are in a kilometer?

Take this, for an example, the definition of an inch:

An inch is an Imperial unit of length Quick Summary:
The linear extent in space from one end to the other; the longest horizontal dimension of something that is fixed in placelength. Sweden also briefly had a "decimal inch" based on the metric system: see below for more.

According to some sources, the inch was originally defined informally as the distance between the tip of the thumb and the first joint of the thumb. Another source says that the inch was at one time defined in terms of the yard Quick Summary:
The enclosed land around a house or other buildingyard, supposedly defined as the distance between Henry I of England Quick Summary:
Quick Summary not found for this subjectHenry I of England's nose and his thumb. There are twelve inches in a foot Quick Summary:
The foot of a human beingfoot, and three feet in a yard Quick Summary:
The enclosed land around a house or other buildingyard.

The word for "inch" is similar to the word for "thumb" in some languages. French Quick Summary:
The Romance language spoken in France and in countries colonized by FranceFrench: pouce inch, pouce thumb; Italian Quick Summary:
A native or inhabitant of ItalyItalian: pollice inch, pollice thumb; Spanish Quick Summary:
The Romance language spoken in most of Spain and the countries colonized by SpainSpanish: pulgada inch, pulgar thumb.

Historically, the inch has referred to several slightly different units of length, used in different parts of the world. There was little uniformity; different countries, and even different cities within the same country, used their own standard length. Today there are two units called the "inch" still in use, both being largely confined to the United States. Other countries, which previously had their own separate definitions of the inch, have converted to using the metric system instead. When the inch being referred to is not specified, it almost always means the international inch.

The international inch is defined in terms of the metric system of units to be exactly 25.4 mm Quick Summary:
A metric unit of length equal to one thousandth of a metermm. This definition was agreed upon by the US and the British Commonwealth in 1958. Prior to that, the US and Canada each had their own, slightly different definition of the inch in terms of metric units, while the UK and other Commonwealth countries defined the inch in terms of the Imperial Standard Yard. The definition adopted was the Canadian definition. A metric inch was also used in some Soviet clones of Western computers. The clones were a slightly scaled copy, and hence Soviet parts didn't match exactly with Western ones.

However, the US continued to use its previous national definition of the inch for surveying Quick Summary:
The practice of measuring angles and distances on the ground so that they can be accurately plotted on a mapsurveying purposes. This inch, known as the US survey inch, is defined so that 1 metre is exactly 39.37 survey inches. 1 survey inch equals approximately 25.4000508001016002032004(...) mm, or about 1.000002000004000008(...) international inches. Whilst the difference between the two units is only approximately two parts per million, the difference between the two units makes a significant difference of many meters when the unit is used to define measurements made on the scale of distances of thousands of kilometers. Yeah, sure. Whatever they say.

OK, here's a pound:
Pound (avoirdupois) or international pound

The pound (avoirdupois) or international pound, abbreviation "lb" or sometimes # Quick Summary:
Quick Summary not found for this subject# in the United States, is the mass unit defined as exactly 0.45359237 kilogram Quick Summary:
One thousand grams; the basic unit of mass adopted under the Systeme International d'Uniteskilograms (or 453.59237 gram Quick Summary:
A metric unit of weight equal to one thousandth of a kilogramgrams). This definition has been in effect since 1959 in the United States. (*)
It is part of the avoirdupois Quick Summary:
A system of weights based on the 16-ounce pound (or 7,000 grains)avoirdupois system of mass units.

In the United States, the pound has been officially defined as a unit of mass Quick Summary:
The property of a body that causes it to have weight in a gravitational fieldmass and defined in relation to the kilogram Quick Summary:
One thousand grams; the basic unit of mass adopted under the Systeme International d'Uniteskilogram since 1893, but its value in relation to the kilogram was altered slightly in 1894, and again to its current value in 1959 (which only differs from the 1894 definition by approximately one part in 10 million).

There are 16 ounce Quick Summary:
A unit of apothecary weight equal to 480 grains or one twelfth of a poundounces in a pound (avoirdupois). The pound is equal to exactly 7000 grains, where a grain Quick Summary:
Foodstuff prepared from the starchy grains of cereal grassesgrain is exactly 0.06479891 gram. The legal definition of the pound in the United Kingdom Quick Summary:
A monarchy in northwestern Europe occupying most of the British Isles; divided into England and Scotland and Wales and Northern IrelandUnited Kingdom and Canada Quick Summary:
A nation in northern North America; the French were the first Europeans to settle in mainland CanadaCanada are the same as in the United States, and were unified to their current value in 1960. Sure, tell me more....

Here's a mile:
mile -
A certain measure of distance, being equivalent in England
and the United States to 320 poles or rods, or 5,280 feet.
[1913 Webster]

Note: The distance called a mile varies greatly in different
countries. Its length in yards is, in Norway, 12,182;
in Brunswick, 11,816; in Sweden, 11,660; in Hungary,
9,139; in Switzerland, 8,548; in Austria, 8,297; in
Prussia, 8,238; in Poland, 8,100; in Italy, 2,025; in
England and the United States, 1,760; in Spain, 1,552;
in the Netherlands, 1,094.
[1913 Webster]

Geographical mile or Nautical mile, one sixtieth of a
degree of a great circle of the earth, or 6080.27 feet.
A pole, eh? That's a new one on me! Please note, that a nautical mile is based on Earth measurements, just like Larry said the meter was...not too much different.

It's the arbitrary conversions from one to the other in Standard that I have a problem with. Nothing is a real standard (go figure). Now, if they came along and said 10 teaspoons are in a tablespoon, and 10 tablespoons are in a cup, and 10 cups are in a gallon, sure-we've got something easy and quick to work with. But, that isn't the way it is.

While they are trying to change the kg, a block of a certain metal, x b y long is a kg. Well, they want to change that to a universal constant. Something that will always be a kg, no matter what. As the article states, over time deposits form on the metal that make it weigh more than it does now, thus affecting the official standard of the kg.

[arod]

Fact is the pound is an arbitrary measurement.

So is the Kg, meter or any other unit of measurement you care to name.

[BrandonL]

So is the Kg, meter or any other unit of measurement you care to name.
Not if these scientists have their way. And, note the pound has changed in size throughout the last 100 years or so...

[jeny]

Here's one you don't need to use a calculator or Google for: how many meters are in a kilometer?



I would need google, I don't know how many places, or which way, to move the decimal point, having never used the metric system. ;)

[BrandonL]

I would need google, I don't know how many places, or which way, to move the decimal point, having never used the metric system. ;)
;) But, see? All you are doing is moving the decimal x places to the right or to the left to move up or down. You aren't dividing by 3, or 5,280, or 12, etc. Simple movement of the decimal place.

Even those computers that you are relying on to do the conversions don't use the standard method of measurement. Take a database server, or programming language-well, it sees today's date as 3/2/2005. It converts that to (most likely) binary, based on a certain start point (take for example 1/1/1900), and counts up the numbers to the current time. it doesn't go by 60 seconds in a minute, 60 minutes in an hour, etc...while the final conversion has to account for leap years and such, at some point the conversion was made to a decimal form of numbering, then back again into something you or I would understand.

I just feel it's a lot easier to simply move the dot from right to left to increase or decrease the units of measure within the same scale, versus having to remember how many units of this are in that. Centi, deci, milli, kilo...all mean a certain number of decimal places.

[jeny]

;) But, see? All you are doing is moving the decimal x places to the right or to the left to move up or down. You aren't dividing by 3, or 5,280, or 12, etc. Simple movement of the decimal place.

Even those computers that you are relying on to do the conversions don't use the standard method of measurement. Take a database server, or programming language-well, it sees today's date as 3/2/2005. It converts that to (most likely) binary, based on a certain start point (take for example 1/1/1900), and counts up the numbers to the current time. it doesn't go by 60 seconds in a minute, 60 minutes in an hour, etc...while the final conversion has to account for leap years and such, at some point the conversion was made to a decimal form of numbering, then back again into something you or I would understand.

I just feel it's a lot easier to simply move the dot from right to left to increase or decrease the units of measure within the same scale, versus having to remember how many units of this are in that. Centi, deci, milli, kilo...all mean a certain number of decimal places.



Blah blah blah. We've been using imperial for so long. I know how much a cup is, I can eye it. I can eye a foot or an inch or a yard. There are certain conversions I know off the top of my head, the ones I use a lot. A mile means something to me. It would be like learning a fopreign language. You might be able to learn it technically, but it would be hard to have it as second nature.

[BrandonL]

It would be like learning a fopreign language. You might be able to learn it technically, but it would be hard to have it as second nature.
Funny that the rest of the planet was able to move to it without a problem, though...eh?

[jeny]

Funny that the rest of the planet was able to move to it without a problem, though...eh?


Funny that Pony said she learned it in the 7th grade but still thinks in imperial. ;)

[BrandonL]

Funny that Pony said she learned it in the 7th grade but still thinks in imperial. ;)
Leave it to the Canuks ;) I have my items that I do well, and items that I don't. I can't really gauge temperature. But length, speed, and weight I can eyeball...I have problems converting standard measures...I can never tell how many cups in a gallow, or pints in a quart...etc...I have to look that crap up ;D

[arod]

Not if these scientists have their way.

It may be universally accepted, but it will still be arbitrary.

[BrandonL]

It may be universally accepted, but it will still be arbitrary.
Suppose they change the meter to the distance light travels in a vaccuum in one second? Well, in a vaccuum, that's pretty much a constant.

However, using the definition of the inch, the pound, and the mile I have given-you don't see a slight problem with the way those measurements are drawn up, as compared to the metric system? I mean, King Richard's nose? Eh?

[BrandonL]

But a 2x4 isn't really 2"x4" either.
Nope...sure isn't...odd that way, eh?

[arod]

Suppose they change the meter to the distance light travels in a vaccuum in one second?

Swell. Then we could measure car speeds in nanometers per hour. ;)

Well, in a vaccuum, that's pretty much a constant.

For strictly scientific purposes, the advantage in such a degree of precision is obvious. Most of us, however, have no reason to care.

However, using the definition of the inch, the pound, and the mile I have given-you don't see a slight problem with the way those measurements are drawn up, as compared to the metric system? I mean, King Richard's nose? Eh?

King Richard's nose hasn't been a part of the English measurement system for at least the last hundred years. The inch is to our system what the meter is to the metric system. Ours is a base 12 system, theirs is base 10. While there are advantages to the latter, there is also at least one disadvantage: while 10 has 2 and 5 as factors, 12 has 2,3,4 and 6. That means, for example, that 11 feet can be divided evenly by any of those numbers without messing with fractions. For the guy pulling the tape measure, that makes things easier in many cases.

[arod]

It seems sort of funny, but then framing used to be done with studs at 18" with lots of randomness and approximation and now it's 16" so there isn't much in the way of standards in construction, it just seems like there are standards.

The standards are dictated by economics. 18" was probably swell when 2x4's were really 2x4's, and before 4x8 panels became widely available.

[Larry_Oldtimer]

Brandon: While they are trying to change the kg, a block of a certain metal, x b y long is a kg. Well, they want to change that to a universal constant. Something that will always be a kg, no matter what. As the article states, over time deposits form on the metal that make it weigh more than it does now.

As I stated, the metre, the focus of linear measurement of the metric system is a measurement of a specified 1/4 of the circumference of the earth, which is in constant change and therefore not at all static. Maybe they should start with that one. Moreover, they can carefully cast another hunk of the specified metal, and shazam, a new and accurate standard. All units of measurement are arbitrary, as arod said. The cost of "going metric" is real and enormous, with no discernable benefits. It would be cheaper to retrain (or simply train properly) the few scientists who make the conversions, or maybe buy them a computer. ::)

[Larry_Oldtimer]

The standards are dictated by economics. 18" was probably swell when 2x4's were really 2x4's, and before 4x8 panels became widely available.


16" on center for studs fits nicely when the standard panel is 4'. All lumber measurements are what are called "nominal" which simply means that they are different than what is said. Architects still design in feet, inches and fractions of inches (civil engineers long since have been using a decimal foot) and I have yet to see any architectural plan which doesn't have a good many mistakes in addition . . . damn fractions.

[jeny]

I was introduced to metric after I finished high school ... as far as I can remember. I think in both metric and imperial. The first thing I learned is that 50 kph = 30 mph and 80 kph = 50 mph because cars were still in imperial but the speed limits were in metric. In design, I have all the defaults for autocad set to imperial because construction materials are in 2x4s, 4x8 sheets of plywood and so on. One industry that has not converted to metric, and where it doesn't work well, is construction. Most teenagers have no idea that a meter is 39 inches and they don't know that there are 12 inches in a foot. But a 2x4 isn't really 2"x4" either.


I see Brandon's point, that in certain scientific disciplines, metric is easier and makes mroe sense. But to most of the rest of the country, it doesn't make sense to scrap the imperial system.

BTW, maybe because you guys are on metric, but while Canadian teenagers may not know there are 12 inches in a foot, but probably most American teenagers do.

[Annie04]

while Canadian teenagers may not know there are 12 inches in a foot, but probably most American teenagers do.


We hope... ;D

[BrandonL]

I really feel it's time to simplify all our measurements. Ok, we have a light year-Distance light travels in a year. OK. An AU-the distance from the sun to the Earth. OK. Well, both are used in astronomy. Suppose we just switched to the standard where a meter was the length light travels in a vaccum for a minute? Well, would definately give us something to work with. Instead of converting light-years to miles, and AUs to meters, etc.

[jeny]

I really feel it's time to simplify all our measurements. Ok, we have a light year-Distance light travels in a year. OK. An AU-the distance from the sun to the Earth. OK. Well, both are used in astronomy. Suppose we just switched to the standard where a meter was the length light travels in a vaccum for a minute? Well, would definately give us something to work with. Instead of converting light-years to miles, and AUs to meters, etc.


Go ahead and make the switch, then. ;)

[BrandonL]

Go ahead and make the switch, then. ;)
Well, generally, a lot of the "scientific" publications are already switched. It's very, very rare to find a scientific publication-it's it's original print-in miles, feet, or inches.

I already know how many meters per second light travels. And, it's a lot easier to work with that number than, say, the number of inches light travels per second. Factor in the enormous distances of space, and you are doing a lot of math.

For us regular folk, we are pretty much stuck with standard. For some reason, Americans were not able to make the switch (even if everyone else was).. For whatever reason.

[jeny]

Well, generally, a lot of the "scientific" publications are already switched. It's very, very rare to find a scientific publication-it's it's original print-in miles, feet, or inches.

I already know how many meters per second light travels. And, it's a lot easier to work with that number than, say, the number of inches light travels per second. Factor in the enormous distances of space, and you are doing a lot of math.

For us regular folk, we are pretty much stuck with standard. For some reason, Americans were not able to make the switch (even if everyone else was).. For whatever reason.


It's not that we wearn't able to it's just that we saw no reason to. In day to day life, one system is just as good as the other.

[Larry_Oldtimer]

I really feel it's time to simplify all our measurements. Ok, we have a light year-Distance light travels in a year. OK. An AU-the distance from the sun to the Earth. OK. Well, both are used in astronomy. Suppose we just switched to the standard where a meter was the length light travels in a vaccum for a minute? Well, would definately give us something to work with. Instead of converting light-years to miles, and AUs to meters, etc.


But . . . but . . . then why call it a meter? Why not call it vacuumlength, shortened to VL in real use? Because it wouldn't mollify the French? I, for one, was pissed when the term "cycles per second" was changed to Hertz. CPS had real meaning, whereas Hertz was only another term, in and of itself meaningless, to memorize. :smarty:

[Lazarus]

I really feel it's time to simplify all our measurements. Ok, we have a light year-Distance light travels in a year. OK. An AU-the distance from the sun to the Earth. OK. Well, both are used in astronomy. Suppose we just switched to the standard where a meter was the length light travels in a vaccum for a minute? Well, would definately give us something to work with. Instead of converting light-years to miles, and AUs to meters, etc.


Light travels a certain speed, C, in a vacuum.

It can go faster or slower if not in a vacuum.

The orbit of the earth is an ellipse, not a perfect circle, so the distance from the Sun varies significantly over an orbit.

Light travels at about 186,200 MPH in one second. In a minute (60 seconds), that means that light has traveled about 1/8 th of the distance between the Sun and the Earth, about 11,172,000
miles...and you prose this as the standard for a meter?

:cwm3: :cwm28:

What possible use (on earth) could it be? ;D ;D ;D

[BrandonL]

The orbit of the earth is an ellipse, not a perfect circle, so the distance from the Sun varies significantly over an orbit. Yet, the AU is still used....go figger. An AU is the mean distance between the sun and the Earth. This is an AU:
An Astronomical Unit is approximately the mean distance between the Earth and the Sun. It is a derived constant and used to indicate distances within the solar system. Its formal definition is the radius of an unperturbed circular orbit a massless body would revolve about the sun in 2*(pi)/k days (i.e., 365.2568983.... days), where k is defined as the Gaussian constant exactly equal to 0.01720209895. Since an AU is based on radius of a circular orbit, one AU is actually slightly less than the average distance between the Earth and the Sun (approximately 150 million km or 93 million miles). Damn, look at all those decimals...hmmm...

Light travels at about 186,200 MPH in one second. In a minute (60 seconds), that means that light has traveled about 1/8 th of the distance between the Sun and the Earth, about 11,172,000
miles...and you prose this as the standard for a meter?
It's an example, Dr Grabthar ;) Just to show that it could be based on some universal constant.

[Larry_Oldtimer]

Brandon: Damn, look at all those decimals...hmmm...

Yeah, sure enough. Lo those many years ago, when I made a living as an auto mechanic, I could set the points of a VW bug at either 0.016 in inches or . . . 0.4064 millimetre ;D

[bison]

I was under the impression all scientists universally used decimal for measurements. Base 10 is easy, easier than 12 in=1foot, 3 ft=yard, etc...

Converting in metric is easy once you know the meaning of the words:
kilo is a thousand
deks is ten (as opposed to deci which is a tenth)
Etc.

I was also under the impression that many lables in the grocery stores were in BOTH metric and english standards. I see drug lables are in metric and english as well.

LarryOT, I am just starting to learn about the dubious joys of the application of Ohms law, but what I don't understand is why there are differently names for the variables...for example W is power, measured normally in watts. I is amperage, measured in amps, but, correct me if I am wrong, can also be used to describe resistance...IN OHMS! what is up with that?!?

I trust I needen't do volts....

GHAAAAA!

[Larry_Oldtimer]

I was under the impression all scientists universally used decimal for measurements. Base 10 is easy, easier than 12 in=1foot, 3 ft=yard, etc...

Converting in metric is easy once you know the meaning of the words:
kilo is a thousand
deks is ten (as opposed to deci which is a tenth)
Etc.

I was also under the impression that many lables in the grocery stores were in BOTH metric and english standards. I see drug lables are in metric and english as well.

LarryOT, I am just starting to learn about the dubious joys of the application of Ohms law, but what I don't understand is why there are differently names for the variables...for example W is power, measured normally in watts. I is amperage, measured in amps, but, correct me if I am wrong, can also be used to describe resistance...IN OHMS! what is up with that?!?

I trust I needen't do volts....

GHAAAAA!


It's been a long time now, but I don't recall "I" ever being used to depict resistance . . . of any kind. Oh, the joys of electricity. Right now, you must be learning about direct (and steady state) current, which is quite straight forward. Wait until you get to alternating current . . . what fun!!! . . . not. ;D

As for the decimal system . . . before calculations are done, all units have to be converted to the same system. There were 3 of them used when I was in college . . . the cgs (centimeter-gram-second, force in dynes), the MKS (meter-kilogram-second, force in newtons) and the English system (foot-slug-second, force in pounds). Of course, all calcs are done in decimal, which means that angular measurements have to be converted from degrees-minutes-seconds to the decimal equivalent, a real pain in the butt, even with modern calculators. ??? One of the joys of a physics professor I had was giving problems in mixed measurement systems . . . some forces in pounds, newtons and dynes, some masses in kilograms, grams and slugs, with lengths in meters, yards, feet or miles and the like . . . which all had to be converted to one of the three systems (depending on what terms the answers were to be given). Needless to say, in those days lo those many years ago, with no calculators, the conversion part often took more than 90% of the time needed to solve the problem.

[arod]

It's been a long time now, but I don't recall "I" ever being used to depict resistance . . . of any kind.

Resistance is R, reactance is XL or XC, and impedance is Z. I think that about covers it.

[bison]

It's been a long time now, but I don't recall "I" ever being used to depict resistance . . . of any kind. Oh, the joys of electricity. Right now, you must be learning about direct (and steady state) current, which is quite straight forward. Wait until you get to alternating current . . . what fun!!! . . . not. ;D


My bad. R is resistance measured in ohms.

Ya. AC stuff doesn't look fun.

BTW, ohms' law has changed slightly:

http://www.installer.com/tech/ohmslaw.html

[bison]

Resistance is R, reactance is XL or XC, and impedance is Z. I think that about covers it.


What are you trying to do, make me respect you?

How many electricians/physicists are in the house?

[arod]

BTW, ohms' law has changed slightly:

http://www.installer.com/tech/ohmslaw.html


No it hasn't. Those are all permutations of E=IR and P=VA.

[Larry_Oldtimer]

And I guess that the topic should have been entitled . . . Kilogram poses massive problems. ;)

[goethe]

keep the step ,we need enegy