Can the US switch to the Metric System?

[Redbelly98]

I have seen a discussion between chemistry teachers on the subject - and I recall that one of the main problems was attributed to the way metric system is taught in US. Instead of concentrating on how easy it is to use, emphasis is put on conversion of feets and inches to meters and centimeters. This is awkward, so most students remember metric system as something confusing and complicated.

Borek, you've gotten me curious: in metric-only classes how do they teach unit conversions? You still have to go between mm-cm-m-km. Are students told to "just move the decimal point"? Or to multiply by a factor such as

1m / 100cm​

in order to cancel units? Or is it done a different way?

 

[Borek]

Honestly - I don't know. I may ask around. I don't remember being taught conversions between m, km and cm - so it was probably done in early primary school, when I was 6, 7 or 8. I remember being shown how much a meter, cm and mm are and that was at this time.

Conversion factors - like 1m/100cm - and units cancellation are not taught in Poland, so conversions must be done through decimal point shifting.

I suppose when you are immersed in these conversions from your early school years, they became so natural, that you don't need any special tools to deal with them, but that's just my guess.

 

[Redbelly98]

Honestly - I don't know. I may ask around. I don't remember being taught conversions between m, km and cm - so it was probably done in early primary school, when I was 6, 7 or 8. I remember being shown how much a meter, cm and mm are and that was at this time.

Conversion factors - like 1m/100cm - and units cancellation are not taught in Poland, so conversions must be done through decimal point shifting.

Thanks for answering that, I had wondered about it. I'm also wondering about when advanced students must eventually learn to use non-metric units like parsecs (in astronomy) or Faradays (in electrochemistry), there must be some kind of unit-conversion calculations that come into play.

I suppose when you are immersed in these conversions from your early school years, they became so natural, that you don't need any special tools to deal with them, but that's just my guess.

Actually no, from what I remember, we don't get into unit conversions until we take a chemistry or physics class in high school.

At least that's how I remember it from when I was in school in the 1970's. And from my recent experiences as a private tutor, this seems to still be the case in the USA. Students do need to have already taken Algebra 1, normally taught in 8th or 9th grade, in order to understand the "canceling of units" concept.

Is anyone else here who was in school more recently than I, exposed to unit conversions before high school? Wish I could remember back that far, but I can't

 

[mgb_phys]

Actually no, from what I remember, we don't get into unit conversions until we take a chemistry or physics class in high school.

Junior school in the UK in 70s - we used cm rulers as number lines for elementary arithmatic but that's the only units stuff I remember.
I do remember we were never taught imperial units - even though that was all we would use in normal everyday. I think metric was new and everyone was keen, but I don't remember being explicitly taught anything.

Students do need to have already taken Algebra 1, normally taught in 8th or 9th grade, in order to understand the "canceling of units" concept.

Dimensional analysis was in high school physics. I still think it's one of the most important topics but a lot of ugrads still don't seem to get it.

 

[LowlyPion]

I think the issue of units conversion education isn't all that important. The real issues I think are economic and inertial. The inertia of society, for which adapting seems elusively profitable, like why bother to change all those signs and wrenches and odometers and scales for what actual benefit?

In school I remember converting meters and rods and bushels and pecks and acres and such, but I rather think it was more designed to forward facility with math skills than in teaching units so much.

I mean crikeys if the idea is to make the world uniform and efficient, let's clean up the arrangement of the keys on a qwerty typewriter while we're at it.

Or make the Latin alphabet the international standard. Loose all those ideograms and decorated characters and just learn English - American Enhanced English of course.

 

[turbo]

Honestly - I don't know. I may ask around. I don't remember being taught conversions between m, km and cm - so it was probably done in early primary school, when I was 6, 7 or 8. I remember being shown how much a meter, cm and mm are and that was at this time.

Conversion factors - like 1m/100cm - and units cancellation are not taught in Poland, so conversions must be done through decimal point shifting.

I suppose when you are immersed in these conversions from your early school years, they became so natural, that you don't need any special tools to deal with them, but that's just my guess.

I envy you, Borek. I am quite a bit older than you, and we were taught everything in British units, until HS chemistry, when we had our first real exposures to milliliters, cubic centimeters, grams, etc. Transitioning to engineering school at college was a mind-bender, because everything was done in metric units. This made calculations MUCH easier, since we were using slide rules, log tables, etc, but my lack of familiarity with the metric system meant that I had no in-bred sense of scale for some units. It was very common for first-year engineering students to have quizzes and test questions down-graded for shifted decimal points, so I wasn't the only one plagued with that.

Students of my age were aggressively pushed into the sciences during the cold war/space race. If the US had done a "soft" conversion to metric before doing that (school courses only, but still sell gas by the gallon and fabric by the yard, etc) a whole generation of university students would have been better-prepared.

 

[BobG]

This made calculations MUCH easier, since we were using slide rules, log tables, etc, but my lack of familiarity with the metric system meant that I had no in-bred sense of scale for some units. It was very common for first-year engineering students to have quizzes and test questions down-graded for shifted decimal points, so I wasn't the only one plagued with that.

Sometimes even having a sense of scale for what the answer should be doesn't help.

I remember totally botching a calculation for the doping concentration for a semiconductor and getting an answer of something time 10^28 (ridiculously high since that's around a 1000 times higher than the concentration of atoms in a semiconductor). Unfortunately, there was no way I would have time to start over, so...

My only consolation was that the girl I studied this with got an answer of 2.

That's a lot worse than my answer. If you walk down the hall laughing, incredulously yelling, "2.3 x 10^28!? 2.3x10^28?!", it just doesn't quite sound as funny as walking down the hall laughing, incredulously yelling, "Two!? Two-oo!? TWO-OOO-OOO?!"

She left town as soon as she graduated.

 

[Office_Shredder]

Except:
1) In a non-test situation, knowing for sure that answer is wrong is a good thing
2) If you wrote "I know this is wrong because it's 1000 times the concentration of atoms in a semiconductor" you probably get extra partial credit

 

[Proton Soup]

I have seen a discussion between chemistry teachers on the subject - and I recall that one of the main problems was attributed to the way metric system is taught in US. Instead of concentrating on how easy it is to use, emphasis is put on conversion of feets and inches to meters and centimeters. This is awkward, so most students remember metric system as something confusing and complicated.

coming back to this, i find it a bit bizarre. probably the most important thing i picked up from chemistry was dimensional analysis. if you can do that, unit conversion should be a breeze. students that don't pursue science, tho, will still have trouble with fractions.

 

[f95toli]

Thanks for answering that, I had wondered about it. I'm also wondering about when advanced students must eventually learn to use non-metric units like parsecs (in astronomy) or Faradays (in electrochemistry), there must be some kind of unit-conversion calculations that come into play.

Well, students are simply not suppose to use non-SI units, I am sure I was told what a Faraday was at some point in high-school chemistry but I don't think we ever used it (I had to look up what is was now); we used Coulomb instead (which is the SI unit).
Same thing with parsecs.
As far as I remember the only non-SI unit I was "officially" taught in school was eV.
Most people -including me- do not really learn to use non-SI units until they start working in a particular field but even then the "units" are often other SI units; I e.g. tend to measure energy and temperature in GHz (using kb and h as conversion factors) since it it quite convenient in my line of work.

 

[Evo]

In school I remember converting meters and rods and bushels and pecks and acres and such, but I rather think it was more designed to forward facility with math skills than in teaching units so much.

One of my most cherished gifts ever was a little vinyl bifold memo pad that had a conversion chart in it, I was 7-8 years old. I carried it with me everywhere I went. This was a piece of paper with the conversions typed on it. We had no computers, no stinking calculators, we used a pencil, paper, and brain cells. And a litttle slip of paper. Of course BobG was using slide rules in the first grade. That reminds me, my first calculator was a plastic pencil box with a little plastic slide that had the basic multiplication tables on it. I know Lowly and BobG know what I am talking about. I felt so guilty about using that thing, but it made memorizing the multiplication tables so easy. I used to play with it at night. Anyway, back to the metric system.

 

[Gokul43201]

On the whole the metric system is ok. It has its problems. For my home projects I will never give up my ft-In tape measure. I like the many prime divisors of our base 12 system.

12 has as many prime divisors as 10.

 

[Redbelly98]

Well, students are simply not suppose to use non-SI units, I am sure I was told what a Faraday was at some point in high-school chemistry but I don't think we ever used it (I had to look up what is was now); we used Coulomb instead (which is the SI unit).
Same thing with parsecs.
As far as I remember the only non-SI unit I was "officially" taught in school was eV.
Most people -including me- do not really learn to use non-SI units until they start working in a particular field but even then the "units" are often other SI units; I e.g. tend to measure energy and temperature in GHz (using kb and h as conversion factors) since it it quite convenient in my line of work.

Well, my example of parsecs and Faradays was to show that scientists in specialty areas do sometimes use non-SI units. I always considered being able to convert between different units as a basic and requisite tool of being a scientist, just like being able to do algebra for example.

Perhaps my thinking is simply from living in America where one is forced to use different units more often. Just to understand my home use of heating and electricity, I need 3 different units for energy and none of them are Joules.

 

[Evo]

Redbelley, I love your avatar!

 

[Borek]

I think I know how one of his next avatars will look alike.

 

[BobG]

One of my most cherished gifts ever was a little vinyl bifold memo pad that had a conversion chart in it, I was 7-8 years old. I carried it with me everywhere I went. This was a piece of paper with the conversions typed on it. We had no computers, no stinking calculators, we used a pencil, paper, and brain cells. And a litttle slip of paper. Of course BobG was using slide rules in the first grade. That reminds me, my first calculator was a plastic pencil box with a little plastic slide that had the basic multiplication tables on it. I know Lowly and BobG know what I am talking about. I felt so guilty about using that thing, but it made memorizing the multiplication tables so easy. I used to play with it at night. Anyway, back to the metric system.

No, but I thought my dad's looked pretty damn cool.

Any calculating device with sliding parts, etc, made a really cool addition to school supplies. I never cared if I needed them or not - they were just fun to use.

Those cardboard slides were really popular for conversions whether for science or just for use around the kitchen. You could get them for free in tons of places (they were just a way of advertising for a company).

 

[Borek]

Any calculating device with sliding parts, etc, made a really cool addition to school supplies. I never cared if I needed them or not - they were just fun to use.

Curta?

 

[Redbelly98]

I think I know how one of his next avatars will look alike.

If you can wait a couple weeks or so, I plan to kill two birds with one avatar.

 

[Borek]

If you can wait a couple weeks or so, I plan to kill two birds with one avatar.

I am patient. I am already waiting over fourty years to become rich, I can wait few weeks for your new avatar.

 

[turbo]

Curta?

When I was a process chemist in a pulp mill, one of the older engineers kept one on his desk. What a cool little machine.

 

[Borek]

When I was a process chemist in a pulp mill, one of the older engineers kept one on his desk. What a cool little machine.

I have seen them only on the web and in SciAm (?) few years ago, but I felt in love at first sight. If they were not that expensive I could buy one just to play with it.

 

[turbo]

I have seen them only on the web and in SciAm (?) few years ago, but I felt in love at first sight. If they were not that expensive I could buy one just to play with it.

He had a number of nice gadgets, including a kind of cylindrical slide rule, circular slide rules, etc.

He was at least 30 years older than me, but not an old fogey - he was an early and enthusiastic convert to HP's RPN calculators and one of the first engineers to splurge on HP's flat pocket-sized programmable scientific calculators.

 

[mgb_phys]

I have seen them only on the web and in SciAm (?) few years ago, but I felt in love at first sight. If they were not that expensive I could buy one just to play with it.

I was tempted by just the poster http://www.vcalc.net/cu.htm

 

[glondor]

Ha, the metric system! believe it or not it was a big bonus for the fuel companies. We here in metric Canada have been overpaying for fuel for 30 years or more. When we moved back to Canada in 1995 gas was 45 cents a liter, it was 98 cents a gallon in Virginia. WOW 45 cents sure sounds cheap! well it is 4 times the price of a us gallon. We regularly have price swings of 10 to 15 cents a liter. Some times several times a week, not so bad i guess till you look at it in gallons. Would you tolerate price swings of 60 cents a gallon several times a week in the U.S. I don't think so. It is kind of a mask of the real price we pay as most of the current generation cannot or don't think to compare the relative price VS the rest of North America. After all the price of a liter is always less than the price of a gallon isn't it? AHHHH Tools having to buy 2 sets of every wrench, socket, drill, gauge is a real pain. Makes the tool box heavy for sure. Right at this point I cannot think of a real positive for the metric system. I mean come on 100 grams of lunch meat for $3.99 Is that a deal? Dunno. If you change the market will fill the vaccume created by the lack of knowlage and understanding. It is the perfect oppertunity for big business to give you less and charge you more and make you feel ok about it. DON'T DO IT! fwiw.

 

[glondor]

Oh Yeah. When you misplace all those lil decimal points in the metric system stuff can go real bad real fast. From construction grades to french rockets, bad things happen. It is really hard to screw up feet and inches. really hard.

RE measuring.

 

[LowlyPion]

There is always this tale of metric woe:

MARS CLIMATE ORBITER TEAM FINDS LIKELY CAUSE OF LOSS
A failure to recognize and correct an error in a transfer of information between the Mars Climate Orbiter spacecraft team in Colorado and the mission navigation team in California led to the loss of the spacecraft last week, preliminary findings by NASA's Jet Propulsion Laboratory internal peer review indicate.

"People sometimes make errors," said Dr. Edward Weiler, NASA's Associate Administrator for Space Science. "The problem here was not the error, it was the failure of NASA's systems engineering, and the checks and balances in our processes to detect the error. That's why we lost the spacecraft ."

The peer review preliminary findings indicate that one team used English units (e.g., inches, feet and pounds) while the other used metric units for a key spacecraft operation. This information was critical to the maneuvers required to place the spacecraft in the proper Mars orbit.

"Our inability to recognize and correct this simple error has had major implications," said Dr. Edward Stone, director of the Jet Propulsion Laboratory. "We have underway a thorough investigation to understand this issue."

Two separate review committees have already been formed to investigate the loss of Mars Climate Orbiter: an internal JPL peer group and a special review board of JPL and outside experts. An independent NASA failure review board will be formed shortly.

"Our clear short-term goal is to maximize the likelihood of a successful landing of the Mars Polar Lander on December 3," said Weiler. "The lessons from these reviews will be applied across the board in the future."

Mars Climate Orbiter was one of a series of missions in a long-term program of Mars exploration managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, Washington, DC. JPL's industrial partner is Lockheed Martin Astronautics, Denver, CO. JPL is a division of the California Institute of Technology, Pasadena, CA.

http://mars.jpl.nasa.gov/msp98/news/mco990930.html

 

[Redbelly98]

Yup, that will forever be the classic screw-up that people remember. But even within the metric system mistakes can happen:

A former boss of mine once sent a drawing to a machine shop to get a part made, telling them that it was in metric units. What he did not tell them was that he had used cm, rather than mm which is standard in this line of work. The part arrived, 10 times smaller than it should have been.

By the way, this happened after he had previously given them the drawing with no mention of units whatsoever, in which case the shop assumed inch dimensions and the part that arrived was 2.54 times too big.

Moral of the story: always specify the units. Even when everybody involved is using metric.