The NOAA NWS global computer forecasts are done in SI only. When these are
reduced to local forecasts, units are converted to meet public and user needs.
For example, forecasters work in hPa for weather maps but convert to inches of
Hq as required by the aviation industry and the public. hPa is metric and
identical to the metric millibars (mbar) which has been discontinued. So the
numbers are identical and have not been changed; it was only a name change.
The aviation industry dictates that pressure be given in inches of mercury in
most of the world but not in Russia.
Stan Doore
----- Original Message -----
From: Mike Millet
To: U.S. Metric Association
Sent: Thursday, January 18, 2007 8:46 AM
Subject: [USMA:37776] RE: piecemeal metrication
Regarding the temperature, although I thought it was the National Weather
Service policy to do temperature and forecasting in SI the meteorologists I've
been talking to locally say that when they get the figures they're back to
using Farenheit and pressure in inches.
So yes a firm cut off date must be set for everything. I know of one
meteorologist who's considering at least putting dual units up on his forecasts
locally but his manager stopped the ball on that one fairly quickly.
Mike
On 1/18/07, STANLEY DOORE <[EMAIL PROTECTED]> wrote:
----- Original Message -----
From: STANLEY DOORE
To: [EMAIL PROTECTED] ; U.S. Metric Association
Sent: Thursday, January 18, 2007 2:51 AM
Subject: Re: [USMA:37773] RE: piecemeal metrication
Converting to metric needs a good basic understanding (definitions) of
what accuracy and precision are. This must be taught in elementary school
since it applies to all types of measurement.
Teaching and using the SI exclusively in science course's and classes at
all levels can quickly get students, the future consumers, to understand what
the SI is and how it is used in every day living. The packaging industry is in
the process of resizing packages for products since this is needed to ensure
rationalized uniformity. Note the comparison discussion of the milk jugs
(gallon vs. quadlitre) in the photo distributed to this list. This is a good
example of packagers in the process of preparing to change to SI packaging to
meet law and regulation requirements.
Certain consumer products such as automobiles and other machinery are
already metric because consumers aren't involved in designing and building
them, only on using them. Before tire and pressure cookers etc pressures are
used exclusively, weather observations and forecasts must be presented and used
by the public in SI as common practice. This change needs to be done in matter
of months with a firm cut-off date of non-SI units to be effective .
Regards, Stan Doore
----- Original Message -----
From: Mike Millet
To: U.S. Metric Association
Sent: Thursday, January 18, 2007 1:46 AM
Subject: [USMA:37773] RE: piecemeal metrication
I do mean that they would convert it before solving the problem.
Another issue that arose was that the conversion might not have been exact
because the students wanted to round the number. The professor pointed out just
how dangerous rounding a number in engineering can be :).
I think with enough forced exposure the class will come around but the
fact that we have to have this discussion at a university level speaks to the
sad state of education in sciences and mathematics that my state has. I know
many other states are much better about it. I credit the state school system
and in particular my third grade teacher for pounding every one of those
conversions into our heads until we could recite them in our sleep :).
As I recall the incentive for properly reciting all the major
conversions in distance, weight, temperature etc was a gold star and a cookiee.
Maybe the professor will have better luck if he tries that approach on the
rebellious students :). Juvenile as it may be sometimes it helps to get down to
the student's level.
Mike
On 1/17/07, Martin Vlietstra <[EMAIL PROTECTED]> wrote:
In my first test in the physics class at University we were set a
problem involving Bernoulli's equation of fluid flow. There was a real
mish-mash of units - inches, centimetres, metre/second, pressure in psi,
accelatation due to gravity as 9.8 m/s^2 and so on. The test was to see who
had the sense to reduce everything at a compatible set of units. Very few
student got it right and since we wer ein teh top tutorial group (everybody in
our group having gat an "A" at secondary school) we had a right dressing down
from the professor. I will never forget it.
I now explain it as "Je ne par mix mon units" or "Ich mussen mir
units nicht mixen" Perhaps the American version would replace the French or
German with Spanish.
----- Original Message -----
From: Mike Millet
To: U.S. Metric Association
Sent: Wednesday, January 17, 2007 4:09 PM
Subject: [USMA:37764] RE: piecemeal metrication
I agree that the best transition is a fast one but you won't find a
president on either side of the aisle that is willing to be brave enough to
change "everything" at once. Maybe a few things like metric only package
labelling and even switching to Celcius but no president is going to push for
metrication during his four year term even though it's doable. They'd have to
have tremendous political capital and be able to cast it in such a good light
that every American would agree it's a good thing to do and as many of us know
getting Americans to agree about anything at all is nigh on impossible :).
Besides, I would foresee that if the presidential administration
DID switch to SI totally during that four years the one after him would
champion "Going back to the grassroots that America was founded on" and start
rolling back the changes.
The only way to set the law in stone towards SI is to do it
gradually until people think that there has never been anything but that and
they're used to it. We may even have to go so far as letting the contractors
that build our roads do so in feet and inches provided they sign them in meters
and kilometers until the generation of engineers that prefer and have fought
the government on that retires and a newer one can take its place. Old habits
die hard.
We had a maths class that brought this up the other day. The
question was something along the lines of "Find the vertical clearance of a 2km
long pipe that has an eight percent slope" I did it and came out with 160m
vertical clearance from beginning to end.
Out of the class of 30 students, I was one of perhaps 2 or three
people who even knew what a meter was. Of course in Idaho teaching metric is
mandated but most teachers simply ignore it or brush over it. About half the
studen'ts asked the professor if we would be tested on metric equations and he
said yes. He then encouraged us to learn the conversions between meters and
kilometers etc. The 20 or so students that were asking the question then asked
him if it would be okay if they converted the answer to inches and feet and
solved it. He of course replied no because that's not the format the question
was in and furthermore we should all know the conversions anyway for our own
good.
Thus ensued a ten minute long debate about how "This is America and
we do things this way" etc :). Several of the students made up their minds to
convert any SI unit they saw to the equivalent USC and then work problems that
way no matter how messy or complicated it got and threatened the teacher with
being dragged in front of a review board if he dared to mark them wrong for not
being in the correct units.
This is an extreme example but it makes the poiint that there are
still strong pockets of resistence to overcome. I felt bad for my professor
having to explain all this and then getting verbally chewed out for it but I
think he'll stand his ground on the issue. Hopefully the rest of us can do the
same and we can keep the ball rolling in the right direction.
Mike
Mike
On 1/16/07, Linda D. Bergeron < [EMAIL PROTECTED]> wrote:
I am going to have to agree with Bill on this one. The US has had
30 years to convert 'slowly'. Not only has it not done so, there are areas of
backslidding. For instance several years ago, at my local Wal-Mart you could
find all kinds of metric measuring cups and scales. Now most everything of that
sort has gone back to Fred Flintstone Units.
Thus we have seen the "slow" way does not work. Congress needs to
get off its duff and carry out its constitutional duty and designate the metric
system as the only lawful system for the US, effective by a specified date. And
then have the political guts to stick by it when this or that special intrest
screams boldy murder.
Although I do not see that happening anytime soon. Even with the
Democrats in control of Congress.
Linda Bergeron
----------------------------------------------------------------
From: Bill Hooper <[EMAIL PROTECTED] >
Reply-To: [EMAIL PROTECTED]
To: "U.S. Metric Association" < [email protected]>
Subject: [USMA:37754] piecemeal metrication
Date: Tue, 16 Jan 2007 12:49:20 -0500
On 2007 Jan 16 , at 8:38 AM, Mike Millet wrote:
That's why the best and smoothest transition in the US ...
(will be) ... rather from slow gradual economic and societal change.
"Slow" and "gradual" means difficult and expensive. During a
long, slow transition, both the old and new systems would be in effect causing
a great deal of confusion and extra work. Furthermore, when two systems are
both in effect, people would tend to continue using the old, familiar system.
They would not "gradually become familiar" with the new one.
Mike goes on to say:
give the US consumer some time ... (to become accustomed to
dual labeling) ... then gradually introduce temperature and fuel and finally
road signage changes.
It's difficult to change one things at a time because there are
so many interconnections between units. If one changes fuel measurement at one
time and road signage (including distance) at another time, when do you change
fuel economy figures from miles per gallon to kilometres per litre (or litres
per 100 kilometres)?
Do you first change from miles per gallon to miles per litre
(when litres are adopted) and then change from miles per litre to kilometres
per litre at a later time (when kilometres are adopted). That would mean having
to make TWO changes instead of just one for fuel economy alone (in addition to
the necessary changes from gallons to litres and from miles to kilometres.
Thus, instead of making a total of three changes at one time:
gal. to L,
mi. to km,
mi/gal to km/L
you'd have to make FOUR changes spread out over an extended
period of time:
gal. to L,
mi./gal. to mi./L,
mi. to km,
mi./L to km/L.
Another example would be cooking times based on oven
temperature and amount of food. We have charts or directions in Fahrenheit and
pounds; we will need to get to Celsius and kilograms.
Do we make TWO changes, first from Fahrenheit+pounds to
Celsius+pounds and later a second change from Celsius+pounds to
Celsius+kilograms? How foolish when we can do it in one change if we convert
all things simultaneously.
There are other relationships that cause would cause problems,
too. We know (actually I had to look up this first one) that there are 231 in^3
in a gallon and 1000 cm^3 in a litre. If we convert volumes from gallons to
litres before we convert inches to centimetres, then in the interim (when we
are using litres and inches), do we need to know how many cubic inches there
are in a litre? (The answer is 61.023 7441, by the way.) Again, MORE
conversions are needed when changes are made in several steps instead of all at
once.
Regards,
Bill Hooper
Fernandina Beach, Florida, USA
==========================
SImplification Begins With SI.
==========================
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