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HP Forum Archive 17

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35s - English Conversions
Message #1 Posted by Jeff O. on 31 May 2007, 1:51 p.m.

I’ll start by stating that I am fairly stunned by the 35s, and if it is produced exactly as it looks in the first view, with the presumed function set, no I/O and no matrix functions, I’ll probably buy two or three. However, as a point of discussion, I was wondering what others thought of the lb<->kg, F<->C, l<->gal, mile<->km and in<->cm functions. I don’t recall seeing any discussion of the inclusion of these conversions. I realize that the 33s has such conversions, but the 35s actually expands on them by adding a second distance conversions, mile <-> km. (I guess now I won’t have to remember how many inches are in a mile.) I'll readily admit to still thinking in and using feet, miles, pounds and degrees Fahrenheit, so those conversions may be useful to me and a few others. However, I don’t require the rest of the world to make any concession or suffer any detriment because of the continued use of English measurements in the US. So the prominent inclusion (shifted functions on five keys) of such conversions on a product that will be sold internationally seems like a waste of keyboard space. I'd be perfectly happy with an Engl<->SI function (or similar) that would bring up a menu of those conversions. That would free up a shifted function on one key and two shifted functions on four more keys. Maybe Int÷ and Rmdr on one key, FP and IP on another, and ??? and ??? on the third and fourth. As for the other shifted function for the first key, I’d go with MATRIX for a menu of matrix functions.

edited to reflect the fact that there are five conversion keys - missed the liters to gallons conversions the first time around.

Edited: 1 June 2007, 7:18 a.m. after one or more responses were posted

      
Re: 35s - English Conversions
Message #2 Posted by Egan Ford on 31 May 2007, 2:00 p.m.,
in response to message #1 by Jeff O.

I though about raising that issue as well. I think it is a waste of space. A better solution would be a UNIT menu with 48/49/50 like units support. I think this is critical in a sci calc. My 8th grade Chem teacher beat in to me the notion of always calculating with units. It has saved me a few times. Would have saved others as well.

The freed up space could support Matrix, R<>P, more integer and string functions. STO could be restored.

Edited: 31 May 2007, 2:03 p.m.

      
Re: 35s - English Conversions
Message #3 Posted by Hugh Evans on 31 May 2007, 2:21 p.m.,
in response to message #1 by Jeff O.

I think those quick unit conversion keys will be pretty useful. In terms of tracking units while doing calculations, I never do so on a calculator... That part belongs on paper as far as I'm concerned.

            
Re: 35s - English Conversions
Message #4 Posted by Walter B on 31 May 2007, 2:31 p.m.,
in response to message #3 by Hugh Evans

Are you sure your post is logically consistent? I miss a "not" in the first sentence... d;-)

            
Re: 35s - English Conversions
Message #5 Posted by Patrice on 31 May 2007, 3:22 p.m.,
in response to message #3 by Hugh Evans

If you look carefully at the pictures, you will see that it is units conversion, not units attach to the values.

So it is not even usefull to what you say.

Patrice

                  
Re: 35s - English Conversions
Message #6 Posted by Hugh Evans on 31 May 2007, 4:06 p.m.,
in response to message #5 by Patrice

Exactly, that's why I'm saying that I don't have any big problems with it. Having a quick unit conversion is more useful to me than attaching the units to stack objects. It's a feature I don't think HP will change on the 35s. At the very most we may be able to convince them to make a few changes to the layout and hopefully the label colors, but I wouldn't bank on them changing too much else.

-Hugh

      
Re: 35s - English Conversions
Message #7 Posted by Patrice on 31 May 2007, 3:18 p.m.,
in response to message #1 by Jeff O.

Hi all,

I don't remember having used english units conversion more than once every two years (or even less).

Those keys are really a waste of space.

By the way I am in France

Patrice

      
Re: 35s - English Conversions
Message #8 Posted by Jürgen (CH) on 31 May 2007, 3:31 p.m.,
in response to message #1 by Jeff O.

For those using SI units (some of them use also this strange umlaut characters) these conversion functions are not very useful. I would put them into a menu and use the keys for other (more generally useful) stuff. Personally, I also dislike the light grey of the cursor keys; the light color is too attracting and disturbs the otherwise very nice design. Anyway, it's by far the most interesting calculator HP presented in the last few years. I definitely would buy one.

Cheers, Jürgen

            
Re: 35s - English Conversions
Message #9 Posted by Steve Borowsky on 31 May 2007, 4:01 p.m.,
in response to message #8 by Jürgen (CH)

These conversions have become standard fare on scientific calculators, probably as a concession to grammar school usage. In light of this, the reason for having them on the keyboard and not in a menu is so that when the calculator is hanging on a shelf next to all the TI's, Casio's, and Sharp's which have them on the keyboard the HP isn't passed by for lack of them. Hp has given us most of what we wanted in the 35s, but they have to draw the line somewhere! Just my opinion, of course.

                  
Re: 35s - English Conversions
Message #10 Posted by Egan Ford on 31 May 2007, 4:13 p.m.,
in response to message #9 by Steve Borowsky

I would agree if the 35s were the same price as the Casio/TI. Grammar school kids do not need a $65-$75 programmable calculator. IMHO, professionals do not need a handful of trivial conversions.

                  
Re: 35s - English Conversions
Message #11 Posted by Jürgen (CH) on 31 May 2007, 5:07 p.m.,
in response to message #9 by Steve Borowsky

Steve,

I see your point. Often, we have to find a compromise between sales/marketing and engineering requirements. But doing things the same way as others is not very innovative. Perhaps HP can do better than others? But, as I said above, the conversion functions are not a major problem for me. I will definitely buy a 35s!

Best Regards, Jürgen

                  
Re: 35s - English Conversions
Message #12 Posted by Les Wright on 31 May 2007, 8:54 p.m.,
in response to message #9 by Steve Borowsky

Does anyone have a guestimate as to MSRP?

I am expecting it will be priced similarly to the 12c--maybe cheaper. Certainly more than the 33S.

Does $79.99US sound about right?

Les

                        
Re: 35s - English Conversions
Message #13 Posted by e.young on 31 May 2007, 10:07 p.m.,
in response to message #12 by Les Wright

I would expect it to be around the cost of the 33s.

      
How about overlays and User key assignment
Message #14 Posted by Donald on 31 May 2007, 5:20 p.m.,
in response to message #1 by Jeff O.

Quote:
... So the prominent inclusion (shifted functions on four keys) of such conversions on a product that will be sold internationally seems like a waste of keyboard space. ..

Less useful functions could be depreciated, if a USER mode with key assignments was included on the calculator.

Now there are raised edges on the keyboard sides, it's once again possible to have HP41/HP48 style overlay sheets - so you can write your own yellow shift layout.

Plus, I wonder if there's a flag which sets English or American conversions for gallons.

Edited: 31 May 2007, 5:28 p.m.

            
Re: How about overlays and User key assignment
Message #15 Posted by Steve Borowsky on 31 May 2007, 6:26 p.m.,
in response to message #14 by Donald

Quote:

Less useful functions could be depreciated, if a USER mode with key assignments was included on the calculator.


Well, if they included user key assignments, then they've obviously placed the conversions there intentionally so that we would have some keys to reassign without having to bump anything useful off the keyboard. HP is back baby!

      
Re: 35s - English Conversions
Message #16 Posted by Paul Dale on 31 May 2007, 6:02 p.m.,
in response to message #1 by Jeff O.

I like having the metric-imperial conversions on the keyboard. This is arguably the main reason I bring out my 32SII these days. Well when I don't do the conversions in my head.

I'm in Australia and we officially switched to metric some thirty years ago. I started learing imperial units in school but switched to metric part way through. I am, however, much more conversant in metric. Despite this, imperial units still seem to crop up moderately frequently especially in the building industry.

Working for a parent company that is American also promotes the need for these functions.

- Pauli

            
Re: 35s - English Conversions
Message #17 Posted by Walter B on 31 May 2007, 6:30 p.m.,
in response to message #16 by Paul Dale

If the HP35s shall have (at least almost) the same quality as the original HP35, we have a good chance USA will switch to metric within the lifetime of this calc, and these keys will become absolutly obsolete outside of fantasy novels. Uh, oooh, why do you throw tomatos?!? d;-)

                  
Re: 35s - English Conversions
Message #18 Posted by blurdybloop on 31 May 2007, 7:49 p.m.,
in response to message #17 by Walter B

Ahem. The US has been officially metric for the past 150 years.

All those US measures with similar names to imperial units are actually defined in US law in terms of metric units. For example, a US inch is exactly 2.54cm, not whatever the old imperial inch happened to be.

The difference is that, unlike most other countries, the US government does not attempt to force its citizens to use metric units; and Americans gravitated to whatever units are most convenient for the task at hand. To a lesser extent, this is also done in the UK and Canada. Even "all-metric" countries like Japan retain traditional units of area measure.

The advocates of mandatory metrification base their arguments upon faith rather than reality. Metric is, in many ways, just as arbitrary and unscientific. The origin of the meter is a flawed 18th century understanding of the circumference of the earth -- a flaw that was known back when when it was defined, but they went with it anyway! The kilogram is even more embarassing, as it continues to lose mass over time.

For some calculations, the use of order of magnitude unit levels is more convenient. In others, it is less convenient; base 10 handles negative powers of 2 poorly, and is even worse with other common fractions.

The standard argument is the difficulty in doing arithmetic with measures that mix inches/feet/yards, ounces/pints/quarts/gallons, ounces/pounds/tons, etc. That argument is bogus, because nobody does such arithmetic. These are contrived examples.

For what it's worth, I'm equally comfortable in both metric and US units, and use whatever unit is most suitable for the task at hand.

                        
Re: 35s - English Conversions
Message #19 Posted by John Gustaf Stebbins on 31 May 2007, 8:18 p.m.,
in response to message #18 by blurdybloop

Most countries that are all metric have had the advantage of not having significant industrial activity prior to adoption of SI or have needed to rebuild industry after war or catastrophe. Hopefully, we in the US will continue to struggle with mixed units well past my lifetime.

There is a great book by Underwood Dudley called "Mathematical Cranks." He points out that the English system was actually derived with computational ease in mind. It is complicated in that we have not kept all the units, so conversions are 4 or 8 or 2, but origianally most of the unit sets had units for all powers of two. Thus any computation could be done through unit shifting and simple binary procedures. Much simpler for merchants in the day when a calculator was called an abacus, and it was a fancy new machine from Asia that they really didn't know how to work.

-jgs

                              
Re: 35s - English Conversions
Message #20 Posted by bill platt on 31 May 2007, 10:12 p.m.,
in response to message #19 by John Gustaf Stebbins

Yes, that is an interesting point about mental calcs.

For instance, a dozen (which is after all essentially the word for "twelve" in french) is evenly divisible by 2 3 and 4 and 6, whereas the metric "10" is evenly divisible by 2 only!

Similarly, base 60 (which is after all a base 12 relative) has many convenient divisions.

Even the old English money system was very interesting and useful for division--it was a rich mixture of base 12 and base 20 which made possible dividing into thirds.

Edited: 31 May 2007, 10:12 p.m.

                                    
Re: 35s - English Conversions
Message #21 Posted by GE on 1 June 2007, 3:41 a.m.,
in response to message #20 by bill platt

Hello,
10 ENTER 5 /
!!!!

                                          
Re: 35s - English Conversions
Message #22 Posted by bill platt on 1 June 2007, 7:19 a.m.,
in response to message #21 by GE

:-)

                                    
Re: 35s - English Conversions
Message #23 Posted by Walter B on 2 June 2007, 12:31 a.m.,
in response to message #20 by bill platt

If we would calculate in a duogesimal number system today, you would be perfectly right. But mankind has chosen decimal some centuries ago.

There are few survivors of ancient times, most prominent is HMS. You even find "quatre-vingt" in French, pointing to an old base-20 system. But all such are well countable exceptions in the sea of decimal.

                              
Re: 35s - English Conversions
Message #24 Posted by blurdybloop on 1 June 2007, 6:04 p.m.,
in response to message #19 by John Gustaf Stebbins

Quote:
Most countries that are all metric have had the advantage of not having significant industrial activity prior to adoption of SI or have needed to rebuild industry after war or catastrophe. Hopefully, we in the US will continue to struggle with mixed units well past my lifetime.

The real issue is not Americans struggling with mixed units -- few actually have any "struggle" at all! -- but rather that non-US companies resent having to having a second set of tooling if they want to make non-OEM parts for US products. It makes it more expensive for them to compete with American makers; and they see our use of non-metric units as an anti-competitive measure.

                        
Re: 35s - English Conversions
Message #25 Posted by bill platt on 31 May 2007, 10:27 p.m.,
in response to message #18 by blurdybloop

Some metric units are annoying for their lack of reality. Celsius is too coarse for instance, and "goes negative" in perfectly normal weather. Degrees F on the other hand goes 0 to 100 in temperate climates--and 0 and 100 are pretty much the extremes for much of the temperate world's populations. Furthermore, celsius doesn't get absolute zero any better than Rankine.

Luckily for metric, some of its units happen to mesh quite closely with our traditional measures:

** A meter is very close to a yard, and 2 meters isn't too far off from a fathom (an arm-spread).

** A metric ton (1000 kg) is almost the same as a Long Ton--they differ by only 36 pounds out of 2240.

And the fact that a cubic meter of fresh water weights essentially 1 tonne is also useful.

But metric unit naming is stupid. What lame-brain decided to name all the derived units after people? How the hell are you supposed to remember what a Pascal is? And what about the Bar? Why confuse everything! In "english units it is easier: psi or ksi for pressure--and that's "metric" scaling!--or "atmosphere". The Bar isn't quite an atmosphere but who's quibbling.

At least the Newton can be remembered through the fabled apple incident!

Edited: 31 May 2007, 10:28 p.m.

                              
Re: 35s - English Conversions
Message #26 Posted by cfh on 1 June 2007, 7:30 a.m.,
in response to message #25 by bill platt

Do I treat that as "serious", or "ironic"?

Have you ever worked in metric units?

/cfh

                              
Re: 35s - English Conversions
Message #27 Posted by cfh on 1 June 2007, 12:24 p.m.,
in response to message #25 by bill platt

Quote:
Some metric units are annoying for their lack of reality. Celsius is too coarse for instance, and "goes negative" in perfectly normal weather. Degrees F on the other hand goes 0 to 100 in temperate climates--and 0 and 100 are pretty much the extremes for much of the temperate world's populations. Furthermore, celsius doesn't get absolute zero any better than Rankine.

Luckily for metric, some of its units happen to mesh quite closely with our traditional measures:

** A meter is very close to a yard, and 2 meters isn't too far off from a fathom (an arm-spread).

** A metric ton (1000 kg) is almost the same as a Long Ton--they differ by only 36 pounds out of 2240.

And the fact that a cubic meter of fresh water weights essentially 1 tonne is also useful.

But metric unit naming is stupid. What lame-brain decided to name all the derived units after people? How the hell are you supposed to remember what a Pascal is? And what about the Bar? Why confuse everything! In "english units it is easier: psi or ksi for pressure--and that's "metric" scaling!--or "atmosphere". The Bar isn't quite an atmosphere but who's quibbling.

At least the Newton can be remembered through the fabled apple incident!


OK, so the *Scientific Models* will not sell in the US? Only the Carpenter Models?

cfh, *laughing his eyes out*

                                    
Re: 35s - English Conversions
Message #28 Posted by bill platt on 1 June 2007, 3:01 p.m.,
in response to message #27 by cfh

Of course I am being sarcastic, yet truthful too. Just as it is difficlt to swat a fly with a sledgehammer, it is sometimes awkward to use certain units in certain circumstances and there is nothing inherently superior about one unit over another.

Have I used metric? Heck, that is the one language that American (engineers) are bi-lingual in!

                                          
Re: 35s - English Conversions
Message #29 Posted by Walter B on 2 June 2007, 12:53 a.m.,
in response to message #28 by bill platt

Quote:
Just as it is difficlt to swat a fly with a sledgehammer, it is sometimes awkward to use certain units in certain circumstances and there is nothing inherently superior about one unit over another.
Fully agree. Each metric unit per se is as arbitrary as any Imperial unit. So, why bother? One difference is easier scaling (by powers of 10, never heard of kiloyards so far), but the main advantage is the SYSTEM. Of course, this shines most brilliant in physics, while the carpenter may still live well with his home units (as long as he doesn't have to go from length to area or volume or weight frequently).
                              
Re: 35s - English Conversions
Message #30 Posted by blurdybloop on 1 June 2007, 6:14 p.m.,
in response to message #25 by bill platt

Quote:
Some metric units are annoying for their lack of reality. Celsius is too coarse for instance, and "goes negative" in perfectly normal weather. Degrees F on the other hand goes 0 to 100 in temperate climates--and 0 and 100 are pretty much the extremes for much of the temperate world's populations. Furthermore, celsius doesn't get absolute zero any better than Rankine.

Metric area is particularly bad in this respect. Nobody uses the standard unit of metric area (the are). People either use square meters for smaller areas, or the hectare (100 are or a bit more than 2 acres) for larger areas. Metric measures also don't divide by successive powers of two very well.

That's why many countries continue to use non-metric measures for land measurements, even when they are otherwise metrified.

As for Celsius silliness...the whole reason why 98.6F is supposed to be "normal" human body temperature is that that value is a even 37C. Not that the human body has ever paid attention to metrification!

                                    
Re: 35s - English Conversions
Message #31 Posted by Walter B on 2 June 2007, 12:18 a.m.,
in response to message #30 by blurdybloop

Bullshit. The standard unit for area is m², of course.

The "ar" , though fitting in the system (1 ar = 100 m²), is not. It's seldom used. More popular is the "hektar" (= 100 ar = 10,000 m² - "hekato" means hundred in Ancient Greek) in agriculture or large scale building.

Have you seen the conversion constants? That's the difference in daily life!

                                          
Vorsicht mit unserer Sprache!
Message #32 Posted by Karl Schneider on 3 June 2007, 2:25 a.m.,
in response to message #31 by Walter B

Quote:
Bulls**t. The standard unit for area is m², of course.

"Quatsch", Walter -- "Quatsch!" is mehr hoeflich...

:-)

-- KS

                                                
Re: Vorsicht mit unserer Sprache!
Message #33 Posted by Walter B on 3 June 2007, 3:29 a.m.,
in response to message #32 by Karl Schneider

Karl, I know: Quatsch ist höflicher als "bulls**t" ("Quatsch" is more polite than bulls**t), but since we shall communicate in broken English here, I couldn't find a better expression for the bulls**t written there. Better proposals, however, are welcome. I write straightforward, since I'm not able to command the diplomatic finesses of this language as a native, educated speaker may do. Please accept my apologies.

P.S.: The people here are known for such a language. "Mit dem hab' ich mal deutsch gered't" (= I've talked German to him) means: I've told him very clearly what to do. -- So we find it quite funny to be scared about four-letter-words and 3-year-olds bathing topless, but allow people to carry guns almost everywhere. But that's OT.

Edited: 3 June 2007, 3:36 a.m.

                        
Re: 35s - English Conversions
Message #34 Posted by Jürgen (CH) on 1 June 2007, 2:48 a.m.,
in response to message #18 by blurdybloop

But sometimes it is a good idea to use only a single unit system (or doing at least proper conversions), remember the lost of Mars Climate orbiter. So for NASA the HP 35s would be a good choice because every engineer would be reminded to this problem when looking at its calculator.

Quote:
Mars Climate Orbiter (September 23rd, 1999)

The 125 million dollar Mars Climate Orbiter is assumed lost by officials at NASA. The failure responsible for loss of the orbiter is attributed to a failure of NASA’s system engineer process. The process did not specify the system of measurement to be used on the project. As a result, one of the development teams used Imperial measurement while the other used the metric system of measurement. When parameters from one module were passed to another during orbit navigation correct, no conversion was performed, resulting in the loss of the craft. http://mars.jpl.nasa.gov/msp98/orbiter/


                              
Re: 35s - English Conversions
Message #35 Posted by Walter B on 2 June 2007, 12:03 a.m.,
in response to message #34 by Jürgen (CH)

He, he, he, I've known this, but it's (awkward) fun to read it again. Though the objective was clear!

Quote:
The process did not specify the system of measurement to be used on the project.
IF there was a system of measurement to be used, it cannot be Imperial, because that is no system at all, its just a collection of units for measurement.
                                    
Re: 35s - English Conversions
Message #36 Posted by bill platt on 2 June 2007, 10:15 a.m.,
in response to message #35 by Walter B

Well, "Imperial" (whatever that may mean) may not be a system, yet there are most definitely consistent sets of units that are not metric.

ft-lb-slug-second and it's derivatives is consistent, as is inch-lb etc.

Note that 1 lb accelerates l slug at 1 ft/sec^2, just as one Newton accelerates one kg at 1 meter per second^2.

Of course depending on the scale of the problem, one may choose to use lb-mass and poundals, or inches, or kips instead of lbs etc, but this is not fundamentally different from choosing Mks vs cgs etc in metric.

To say "it" (meaning non-metric) is not a system is quite inaccurate.

It is important (especially for the metricified) to understand that "customary" measure is not the same as "non-metric" or "imperial" and that there are perfectly rational unit systems for science and engineering that are not SI. Frankly imperial is meaningless to me, as I am 'merican.

It is so easy to poke fun at the non-SI of the U.S. but frankly it is myopic to be so disdainful. So much excellent work has been published in non-SI that it behooves the scientist or engineer to be open to the idea of working in many different units. It is after all a trivial exercise but one which for some reason creates a tremendous amount of trepidation.

Edited: 2 June 2007, 10:23 a.m.

                        
Re: 35s - English Conversions
Message #37 Posted by Mike T. on 1 June 2007, 6:03 p.m.,
in response to message #18 by blurdybloop

Nobody does mixed unit calculations...? Hmmm.. what about Hours Minutes and Seconds then - this sort of mixed unit arithmetic seems destined to stay quite popular for some time (excuse the pun).

On a more relevant note I think that unit conversions originally appeared on the HP31E and HP32E, however even though I still think in gallons and fuel is now sold in the UK in litres I find the gallon to litre conversion function on my HP32E less easy to use than I might as it converts to US gallons not imperial gallons, I wonder if the European versions of the HP35s will use a different conversion factor?

Overall I'm impressed by the my first impressions of the HP35s, it doesn't look at all bad, is has enough functionality to keep most people happy most of the time, it looks like it retains the simplicity of 'single key' function entry, and above all it is RPN.

The key question remains - is there enough demand for an RPN calculator to ensure the 35s is a success..?

                              
Re: 35s - English Conversions
Message #38 Posted by Gene on 1 June 2007, 6:12 p.m.,
in response to message #37 by Mike T.

Actually, try the HP45 for the first HP with unit conversions back in 1974.

                              
Re: 35s - English Conversions and the HP-31E
Message #39 Posted by Trent Moseley on 1 June 2007, 10:55 p.m.,
in response to message #37 by Mike T.

Question for Mike T. and anyone else re: the HP-31E. It has some of those conversions, but how does one make efficient use of the trig functions if there is no coversion key from degrees, minutes, and seconds into decimals and vice versa or am I missing something.

tm

                                    
Re: 35s - English Conversions and the HP-31E
Message #40 Posted by Trent Moseley on 5 June 2007, 2:51 p.m.,
in response to message #39 by Trent Moseley

I will ask my question again. Is there a work-around for my problem with the 31E? How does one use the trig functions if it does not do degree/decimal conversions?

tm

                                          
Re: 35s - English Conversions and the HP-31E
Message #41 Posted by Gene on 5 June 2007, 9:11 p.m.,
in response to message #40 by Trent Moseley

You convert them manually before and/or after.

                                                
Re: 35s - English Conversions and the HP-31E
Message #42 Posted by Trent Moseley on 5 June 2007, 10:38 p.m.,
in response to message #41 by Gene

Thank you Gene. This looks like one of the few times HP engineers really dropped the ball big time.

tm

                                                      
Re: 35s - English Conversions and the HP-31E
Message #43 Posted by Trent Moseley on 5 June 2007, 10:50 p.m.,
in response to message #42 by Trent Moseley

One more thought to my last comment. As my dear late father-in-law from the ranch in Salinas would say: They're (i.e. trig functions on the 31E) as useless as tits on a bull".

tm

                                                      
Re: 35s - English Conversions and the HP-31E
Message #44 Posted by Gene on 6 June 2007, 8:37 a.m.,
in response to message #42 by Trent Moseley

Well, the 31E was VERY hampered by having a very small function set. They were only going to have one shift key on that unit, since it was the low end machine. So, what to put in and what to put out?

I've been told that is how PI ended up as a shift function on the top row of keys. Keyboard wars.

I imagine some of the people involved in those decisions wanted the HMS function set, but lost.

            
Re: 35s - English Conversions
Message #45 Posted by bill platt on 31 May 2007, 10:30 p.m.,
in response to message #16 by Paul Dale

I work for an American company but we use metric unless the owner insists otherwise. Go figure.

                  
Re: 35s - English Conversions
Message #46 Posted by db (martinez, ca.) on 1 June 2007, 12:53 a.m.,
in response to message #45 by bill platt

Bill; I think you and blurdlyboop could sit around drinking liters (or quarts) of beer and agreeing about the metric/english thing. I work in both here in California because Caltrans and some other public money jobs require it, this week. It changes.


Most "fine" construction work like carpentry, cement forms and steel is measured in eighths of and inch or hundredths of a foot. They are almost the same thing. 96 eighths = a hundred hundredths. Carpenters know that minimum fall is 1/4 inch per foot without realizing that by definition that is 2%. Centimeters are too coarse and millimeters are too fine for this.


Dirt work: slopes, excavations, building pads, sub grades under roads-railroads-freeways and the like are done to the tenth of a foot. Lots of things are designed and drawn to even inches (1/12 of a foot). Centimeters are too fine and decimeters are too coarse. Most heavy equipment can dig or move a half foot of dirt at a pass. I can hold five fingers down and the operator knows i mean cut 5 tenths. I would have to take off a shoe to do that in France.
Most people can pace even 5 footers with a bit of practice and most mens feet in a shoe are about a foot long. My nose to tip of middle finger is a yard. Surveyors in the US use feet because we are here, and decimal because it works.

I'm not saying that the english system is completely superior but it is based on realistic distances which one can relate to and communicate easily. The metric system makes sense but the scale is off. We'd have been better off basing it on the furlong and gunters chain:
6600 ft = manly mile
660 ft = furlong
66 ft = gunters chain
6.6 ft = basketball player
all the way down to the microfurlong, which a machinist who owns a 41 once told me would be as sensible as thousandths of an inch for his job.
I like working in decimal and feel like i am being punished for something i didn't do wrong if i have to use inches but basing a system of measurement on how far it is from Paris to Santa Clauses House is as bad as using the length of the kings finger joints.

                        
Re: 35s - English Conversions
Message #47 Posted by GE on 1 June 2007, 3:57 a.m.,
in response to message #46 by db (martinez, ca.)

I think you all miss the point, which is that the SI system is DECIMAL. I don't care if the unit is appropriate (example : Farad is much much too big for normal use).
What is appropriate in the DECIMAL system is that when you write a number you usually use also the decimal system (base 10), so it works very conveniently, NO conversion in one's head needed.
Example : 0.00002548756 F is 25 micro Farads, 487 nano Farads and 560 pico Farads. No remembering arbitrary divisors or even calculating at all !! Remember the ENG key.
Splitting evenly in whatever number of equal parts is done by division and not limited to a handful of integer. Do you ALWAYS divide by 2 or 3 ? I sometimes use other numbers... And again, division by 10 needs no actual calculation in the SI System.
Last point, I'd rather use units named after Newton, Einstein (too late for this one), Pascal or other great minds rather than Madonna, Tiger Woods or Spiderman. Your opinion may be different.

                              
Re: 35s - English Conversions
Message #48 Posted by bill platt on 1 June 2007, 7:23 a.m.,
in response to message #47 by GE

The Madonna Unit:

what would it measure?

                                    
Re: 35s - English Conversions
Message #49 Posted by GE on 1 June 2007, 11:33 a.m.,
in response to message #48 by bill platt

:-)

                                    
Re: 35s - English Conversions
Message #50 Posted by John Limpert on 1 June 2007, 5:41 p.m.,
in response to message #48 by bill platt

We already have the milliHelen, which is the amount of beauty needed to launch one ship.

                                          
Re: 35s - English Conversions
Message #51 Posted by cfh on 1 June 2007, 5:49 p.m.,
in response to message #50 by John Limpert

And the MilliVanilli, the amount it takes to playback an old hit song :-)

/cfh

                  
Re: 35s - English Conversions
Message #52 Posted by DaveJ on 1 June 2007, 1:19 a.m.,
in response to message #45 by bill platt

Quote:
I work for an American company but we use metric unless the owner insists otherwise. Go figure.

In PCB design which I do, metric and imperial are both used on the same board (regardless of the country you are in), and it is common to switch back and forth between thousands of an inch and mm on a minute-by-minute basis during a design. So much so that all PCB design software packages have a hotkey to swap between the two units on the fly.

My new calculator will have thous<>mm built in for sure :-P

Dave.

      
Re: 35s - English Conversions
Message #53 Posted by Trent Moseley on 31 May 2007, 8:50 p.m.,
in response to message #1 by Jeff O.

I know this is not a poll, however I vote a big NO to any conversions on the keyboard! My 2¢. From Redwood City, CA USA.

tm

      
Re: 35s - English Conversions
Message #54 Posted by bill platt on 31 May 2007, 9:47 p.m.,
in response to message #1 by Jeff O.

Yes, I think the mile conversion is a total waste: 1.6 / will suffice!

Celsius - Fahrenheit is most useful--it is the sort of conversion that is a pain (because it requires both multiplications and addition) so it is good to have.

lb-kg is internationally useful, as is inch-cm (though inch-mm might be better.)

I actually find myself storing 0.3048 somewhere (0 or Z etc) as converting feet to meters I find more useful than centimeters to inches. Heck, 10 cm is basically 4 inches, and a foot is basically 30 cm (in hard conversions).

Frankly I liked the printed on the back conversions of the 11-c even better.

I don't do a lot of litre conversions. Maybe that one is useful, except that there are different kinds of gallons and so I would nix that one too.

The thing about the conversions is that if they are buried in menus, then they are worthless anyway.

I can type 25.4 / faster than I can dig through menus.

Edited: 31 May 2007, 9:49 p.m.

            
Re: 35s - English Conversions
Message #55 Posted by Meindert Kuipers on 1 June 2007, 9:45 a.m.,
in response to message #54 by bill platt

My personal opinion is that the whole world should go metric. Period.

This whole discussion would not have happened with assignable functions and overlays, much like the HP41 had (still my all-time favourite calc ...)

Meindert

                  
Re: 35s - English Conversions
Message #56 Posted by bill platt on 1 June 2007, 2:05 p.m.,
in response to message #55 by Meindert Kuipers

But Meindert,

The world shouldn't *go* metric any more than the whole world should speak French!

                        
Re: 35s - English Conversions
Message #57 Posted by Peter Geiser on 1 June 2007, 4:16 p.m.,
in response to message #56 by bill platt

Which gallon are you referring to? Not even in America is a gallon always the same:

U.S. liquid gallon is 231 cubic inches, or 3.785411784 litres
U.S. dry gallon is 268.8025 cubic inches, or 4.40488277086 lires
and the Imperial (UK) gallon: 4.54609 litres (defined)

Even worse is the pound:

Metric pound: 500g
Avoirdupois: 453.59g
Troy/ap.: 373.24g
Tower: 349.91g
Merchant: 437.39g
London: 466.55g
Wool: 453.07g
Jersey: 489.94g
Scottish: somewhere between 21 to 28 avoirdupois ounces

In Europe, there was a clear economic reason to abandon the old variety of systems: reduce transaction costs, and thereby increase wealth. But for a mainly self-centric economy such as America this seems to be less of a concern than the concern about the switching costs that would be enormous (see the switch from the old European currencies to the Euro.)

Best regards
Peter

                              
Re: 35s - English Conversions
Message #58 Posted by bill platt on 1 June 2007, 5:14 p.m.,
in response to message #57 by Peter Geiser

Also, while Europeans may hold disdain for our customary units, the fact is that the U.S. has robust standards--even if they aren't the European ones.

ASTM ASME ANSI SAE not only publish standards (including *metric* stsndrds) but also actively participate in the ISO.

Many important facets of the U.S. industries use metric anyway.

                              
Re: 35s - English Conversions
Message #59 Posted by Sam Levy on 1 June 2007, 5:20 p.m.,
in response to message #57 by Peter Geiser

A swiss engineer told me he was to solve a spring and mass resonance problem. He converted the english units to metric and solved the matter in one page. His boss said you can't do it that easily, he took 3 paqges and made several mistakes. The major reason for using metric units is they are not randomly based, but represent a consistent system. I found the kilometer a much more human based unit than the mile, I liked the 100 meter posts on the roadways. I think conversions could easily be accomplished in the constants information stored so the user could multiply or divide by the constant stored. Pi could also be a a srored constant. Teach metric and use metric and the old will die off. We could hope!

                              
Gallons
Message #60 Posted by bill platt on 1 June 2007, 5:37 p.m.,
in response to message #57 by Peter Geiser

Actually in the U.S., only one gallon is used in any great quantity: the Liquid gallon. Things that are sold dry are generally sold in pecks or bushels rather than gallons, or sold by weight. In agriculture there are all sorts of non-metric customary units which are very specific and as they are specific, there is no great need to re-standardize.

For pounds it is even easier: only the Avoirdupois has any widespread use. While the others are fascinating and have some marginal uses, they are not used in normal trade, nor in customary measure.

                                    
Re: Gallons
Message #61 Posted by Norris on 1 June 2007, 6:41 p.m.,
in response to message #60 by bill platt

The legal definition of the "foot" varies slightly in different US states, a point of significant practical importance to surveyors. This is why the HP48 series has both the "ft" and "ftUS" units, as well as both the "mi" and the "miUS" units.

                                          
Re: Gallons
Message #62 Posted by blurdybloop on 2 June 2007, 5:56 p.m.,
in response to message #61 by Norris

Wrong. You're thinking about "survey feet", which has nothing to do with state laws.

Before 1959, there was no standard defintion of the meter vis a vis the foot, or vice versa. In that time, surveying was done with the definition of a foot being 1200/3937 meter. In modern times, the foot is defined as exactly .3048 meters (30.48cm, 304.8mm, take your pick).

The difference between the two is small; 6.09601e-7 meters. But when you take into account that surveys cover large areas, that microscopic difference actually makes a difference.

Hence the survey foot. Now, some states have survey feet specified for their plane coordinate system, and a few have standard feet, leading to the myth that the foot is different in different US states. A foot is .3048 meters in every US state; the question of survey feet is only on SPCs.

The federal government only publishes SPCs in metric, so feet are calculated from the metric values. It's trivial to determine whether these are survey feet or standard feet. I haven't seen much usage of survey feet in new work.

                                                
Re: Gallons
Message #63 Posted by Norris on 2 June 2007, 8:45 p.m.,
in response to message #62 by blurdybloop

The point is that there are two different types of "feet" in the US, and that this issue is of sufficient practical significance to affect the units included in HP calculators.

Note also that while the US accepted the "international foot" in 1959, the standard US definition of the "acre" was not revised at that time. The standard acre is still based on "survey feet", as you can verify with your HP.

It is commonly assumed that 1 acre is 43,560 square feet, or 1/640 of a square mile. But if you try to convert the "acre" unit on an HP calculator into "ft^2" or "mi^2", you will get slightly different results. You can only get the expected results by converting the "acre" to "ftUS^2" or "miUS^2".

You may not see the "survey foot" in new work, but I'll bet you still see areas measured in "acres", which are based on the "survey foot".

Edited: 2 June 2007, 8:48 p.m.

                                                      
Re: Gallons
Message #64 Posted by blurdybloop on 3 June 2007, 6:50 p.m.,
in response to message #63 by Norris

I doubt very much that you will find any acre sized parcels of land anywhere in the world that are exactly 43,560 square feet, whether in survey feet (4046.87260987 square meters) or standard feet (4046.8564225 square meters). Between the two, we're talking about a difference of about 162 square centimeters or about 25 square inches.

Nobody, and I mean nobody, will define either parcel as being more, or less, than one acre.

Furthermore, the definition of 43,560 square feet is for convenience only; 43,560 is simply 5280*5280/160. An acre, by definition, is a 1/640 part of a section. Not all sections are perfect square miles; I doubt there is any section anywhere in the world which is a perfect square mile.

Any calculator which assumes that an acre is defined by survey feet (or standard feet) is defective by design.

Survey feet are an historical curiosity. For most calculations survey feet can be disregarded entirely; they are necessary only in doing metric conversions with some SPCs over large distances (and much of the time you discover that the survey used standard feet so you can disregard that). A far bigger concern is the effect of elevation on SPCs.

                                                            
Re: Gallons
Message #65 Posted by Norris on 3 June 2007, 7:24 p.m.,
in response to message #64 by blurdybloop

Quote:
Survey feet are an historical curiosity.
Practices undoubtedly vary by state, but the survey foot is still explicitly required by at least some government agencies in my state, California. For example, CalTrans is in the process of transitioning to metric units, but their latest guidelines (dated 03/01/05) state:
Quote:
the exact conversion factor from meters to feet is 3937feet/1200meters (the US Survey Foot)...The Party Chief shall ensure that the survey instrumentation is configured to collect data in the U.S. survey foot. Also, the survey reduction and adjustment software shall be configured to use the U.S. survey foot.

Edited: 4 June 2007, 12:18 a.m.

                                                            
Re: Gallons
Message #66 Posted by Norris on 3 June 2007, 8:46 p.m.,
in response to message #64 by blurdybloop

Quote:
Any calculator which assumes that an acre is defined by survey feet (or standard feet) is defective by design.
The definition of the "acre", as implemented on HP calculators, is fully consistent with that specified by NIST.

According to NIST, 1 acre = 43 560 square feet, and 640 acres = 1 square mile. NIST further states that "In these tables where foot or mile is underlined, it is survey foot or U.S. statute mile rather than international foot or mile that is meant."

                                                            
Acres
Message #67 Posted by James M. Prange (Michigan) on 3 June 2007, 10:23 p.m.,
in response to message #64 by blurdybloop

Quote:
Furthermore, the definition of 43,560 square feet is for convenience only; 43,560 is simply 5280*5280/160. An acre, by definition, is a 1/640 part of a section. Not all sections are perfect square miles; I doubt there is any section anywhere in the world which is a perfect square mile.

That's interesting; I've seen the acre described as 160 square rods, 4840 square yards, 43560 square feet, 10 square chains, 160 perches (defined as square rods), as equivalent to 4 roods (a rood is 1 furlong by 1 rod), a rectangle 1 furlong by 1 chain, or 40 rods by 4 rods, or 660 feet by 66 feet, and I've often enough seen the square mile described as 640 acres, and occasionally the acre as 1/640 square mile, all of which are perfectly consistent descriptions, but I've never before read any suggestion that any of these were "approximate" conversions, and never before seen the acre described as a fraction of a section.

For that matter, neither have I seen the section defined in terms of acres, although I think that it's fairly well known that a section was intended to be approximately 1 mile by 1 mile square, although clearly a spherical surface can't be tiled with squares.

By the way, for the conversions that Norris quoted from NIST (which does, after all, have the responsibility for U.S. standards of measure), they're listed by NIST as "exact" conversions.

What about the U.S. National Geodetic Survey? In a glossary, I find:

acre - A unit of area in the English system of measure, defined as 10 square chains (l chain equals 4 rods or 66 feet). An acre is exactly equal to 43,560 square feet or 4,840 square yards, and is approximately equal to 4047 square meters. There are 640 acres in a square mile. By an ordinance of Edward I in 1303, the acre was defined as the area contained in a rectangle 40 rods long and 4 rods wide. With the rod defined as 5 1/2 ulnae (yards), as defined by the Edward I iron standard for the ulna, the acre is again 4,840 square yards. The term "square acre" is meaningless and should not be used.

Regards,
James

                                                      
Re: Gallons
Message #68 Posted by Wayne Brown on 4 June 2007, 2:12 p.m.,
in response to message #63 by Norris

Quote:
The point is that there are two different types of "feet" in the US, and that this issue is of sufficient practical significance to affect the units included in HP calculators.

I think we should abandon "feet" as a measurement altogether and measure all distances in smoots. :-)

                                                
Feet
Message #69 Posted by James M. Prange (Michigan) on 3 June 2007, 6:34 p.m.,
in response to message #62 by blurdybloop

Quote:
Wrong. You're thinking about "survey feet", which has nothing to do with state laws.

Before 1959, there was no standard defintion of the meter vis a vis the foot, or vice versa.


Wrong. In 1866, the U.S. Congress defined the relationship of 1 meter being equivalent to 39.37 inches. See http://lamar.colostate.edu/~hillger/laws/metric-act.html.

So (within the U.S.) 1 meter would be 3937/100 inches, and if we accept that 1 foot is 12 inches, then it follows that 1 meter would be 3937/1200 feet, and if we also accept that 1 yard is 3 feet, then it also follows that 1 meter would be 3937/3600 yard.

In 1866, the U.S. foot and inch would've been defined in terms of the U.S. yard, first adopted by the Treasury department in 1832 and then slightly changed to agree with new standards in 1856. This U.S. yard was intended to be equal to the British Imperial yard.

Eventually, Congress delegated its power to fix the standard of weights and measures to federal agencies. Judging from its performance regarding weights and measures other than coinage, it was probably a relief to shift its responsibility elsewhere.

In 1875, the U.S. was one of the 17 countries signing the Metric Convention, which founded the International Bureau of Weights and Measures. In 1890, the U.S. received its copies of the international meter standard, and a comparison against the U.S. standard didn't show the legal definition of 1866 to be incorrect; that is, they agreed within the error of measurement.

In 1893, the "Mendenhall Order" established the meter as the fundamental unit of length for the U.S., so, based on the 1866 legal relationship, the U.S. yard was redefined as 3600/3937 meter, and therefore the U.S. foot became 1200/3937 meter, and the U.S inch became 100/3937 meter, and for a time, any attempts to maintain the U.S. yard as equal to the British Imperial yard were abandoned.

Quote:
In that time, surveying was done with the definition of a foot being 1200/3937 meter.
Well, presumably, until the U.S. yard was adopted in 1832, the definition of a foot would've been 1/3 British yard, and then would've been 1/3 U.S. yard from its adoption until 1893, and even then still 1/3 U.S. yard, but with the U.S yard being redefined as 3600/3937 meter, the foot would be 1200/3937 meter.
Quote:
In modern times, the foot is defined as exactly .3048 meters (30.48cm, 304.8mm, take your pick).
Well, English-speaking countries which used them had slightly different definitions for the yard and avoirdupois pound and units based on them, which, with the increasing needs for accuracy, increasingly caused difficulties, until in 1959, the directors of the national standards laboratories of Australia, Canada, New Zealand, South Africa, the United Kingdom, and the United States entered into an agreement establishing uniformity for them. The equivalents 1 yard=0.9144 meter and 1 avoirdupois pound=0.453449237 kilogram were adopted for each of these national laboratories, effective July 1st, 1959. So based on that, 1 international foot=0.3048 meter and 1 international inch=0.0254 meter.

But an exception was made for the definitions for the U.S. Coast and Geodetic Survey. I don't know whether other countries made such exceptions.

Measurements expressed in feet and published as a result of geodetic surveys in the U.S. would retain the relationship of 1 foot=1200/3937 meter, and this foot would be referred to as the U.S survey foot, and continue to be used for that purpose until such a time as it becomes desirable and expedient to readjust the basic geodetic survey networks in the U.S., after which the ratio of a yard, equal to 0.9144 meter, would apply.

Has such a time arrived? Or maybe it's already past, and it would be more desirable and expedient to just skip to always using the meter itself for those purposes?

Quote:
The difference between the two is small; 6.09601e-7 meters.
Approximately; the exact difference is 3/4921250 meter. Another way of looking at it is that 1 international foot is exactly 499999/500000 (or .999998) U.S. survey foot.
Quote:
But when you take into account that surveys cover large areas, that microscopic difference actually makes a difference.

Hence the survey foot.


Quite so. Converting all land records from the "old" foot defined as 1200/3937 meter to the "new" foot defined as 0.3048 meter would be an awful lot of work (especially before computers or even electronic calculators were generally available), so the old foot was designated the "U.S. survey foot" and the new foot was designated the "international foot", and such units as the rod (or pole or perch), chain, furlong, U.S. survey mile ("statute mile"), acre, and fathom still retain their definitions based on the U.S. survey foot (at least, within the U.S.).

Note that there isn't a "U.S. survey inch" or a "U.S. survey yard".

For more on the relationship between the U.S. survey foot and the international foot, search within http://physics.nist.gov/Document/sp811.pdf, and good references for the history of the relationship of the metric system to the U.S. customary units include http://lamar.colostate.edu/~hillger/ and http://physics.nist.gov/Pubs/SP447/.

Quote:
Now, some states have survey feet specified for their plane coordinate system, and a few have standard feet, leading to the myth that the foot is different in different US states. A foot is .3048 meters in every US state; the question of survey feet is only on SPCs.
Hmm, in every state, and anywhere else in the world for that matter, a "U.S. survey foot" is always 1200/3937 meter, and an "international foot" is always 0.3048 meter; these definitions don't vary. But just a "foot" can leave me wondering which definition of foot is intended, at least when it's used in land measurement.

It seems to have been left up to the various states to choose which units to use within their own state plane coordinate systems, and apparently some haven't even bothered to choose.

Quote:
The federal government only publishes SPCs in metric, so feet are calculated from the metric values. It's trivial to determine whether these are survey feet or standard feet. I haven't seen much usage of survey feet in new work.
I thought that it was up to the various states to choose which unit to use? It seems bad enough that the states use different units, but surely it would be madness for different surveys within a state to use different definitions of a "foot".

Actually, as Norris wrote, the standard U.S. definition of the acre is still based on the survey foot, and since land area is normally stated in acres in the U.S., it strikes me as rather insane to use international feet for land measurement. Let's see, 1 acre is exactly equivalent to 660 by 66 U.S survey feet, thus 43560 square U.S. survey feet. So 1 acre equals exactly 43560*(500000/499999)^2 square international feet, which works out to exactly 10890000000000000/249999000001 (about 43560.174240522721) square international feet; who wants to work with a crazy conversion factor like that?

Suppose that I'm looking at a property description; how do I know which definition of "foot" is being used? But I grant that for the size of a property, I wouldn't be too worried about the difference; after all, 1 square international foot would be exactly 249999000001/250000000000 (or .999996000004) square U.S. survey foot, not enough of a difference for me to lose much sleep over.

Note that the definition of the meter has changed over time too; see http://physics.nist.gov/cuu/Units/meter.html. That said, as far as I can tell, each new definition of the meter merely reduced the uncertainty in its realization, rather than actually changing its length.

Regards,
James

                                    
Re: Gallons
Message #70 Posted by Peter Geiser on 2 June 2007, 5:08 a.m.,
in response to message #60 by bill platt

Quiz: what is heavier (measured in New York, Wall Street):
a) 3000 ounces of hamburger meat (as used in quarter-pounders)
b) 3000 ounces of gold

Enjoy
Peter

                                          
Re: Gallons
Message #71 Posted by Steve Borowsky on 2 June 2007, 7:42 p.m.,
in response to message #70 by Peter Geiser

Quote:
Quiz: what is heavier (measured in New York, Wall Street):
a) 3000 ounces of hamburger meat (as used in quarter-pounders)
b) 3000 ounces of gold

Enjoy
Peter


Those things are up to 3000 ounces? No wonder obesity is so rampant.
                                    
Pounds/ounces (weight)
Message #72 Posted by Karl Schneider on 2 June 2007, 8:22 p.m.,
in response to message #60 by bill platt

Hi, Bill --

Quote:
For pounds it is even easier: only the Avoirdupois has any widespread use. While the others are fascinating and have some marginal uses, they are not used in normal trade, nor in customary measure.

Of course, the lighter troy ounce is used instead of the Avoirdupois ounce for jewelry and precious metals. Therefore, the answer to Peter's question is "hamburger". :-)

-- KS

Edited: 2 June 2007, 8:36 p.m.

      
Re: 35s - English Conversions
Message #73 Posted by Fred Lusk on 1 June 2007, 8:55 p.m.,
in response to message #1 by Jeff O.

Although I like my HP-42S better than my HP-48G+ for everyday use, one thing I really like about the 48 is the ability to append units to numbers. It's much more useful to me than simple conversions. However, if HP is going to include conversions on the 35S, why not the most useful conversion of all: furlongs per fortnight to/from parsecs per picosecond ???

Fred

BTW: 1 parsec/picosecond = 1.854 x 10^32 furlongs/fortnight

            
Re: 35s - English Conversions
Message #74 Posted by Walter B on 2 June 2007, 1:02 a.m.,
in response to message #73 by Fred Lusk

:-)

            
more SI conversions
Message #75 Posted by db (martinez, ca.) on 2 June 2007, 4:01 a.m.,
in response to message #73 by Fred Lusk

Fred; 10^12 fics = 1 Terafic / 10^-6 fish = 1 microfiche / 2 X 10^3 mockingbirds = 2 kilomockingbirds and 10^-18 boys = 1 attoboy

            
Re: 35s - English Conversions
Message #76 Posted by Peter Geiser on 2 June 2007, 5:47 a.m.,
in response to message #73 by Fred Lusk

Pretty useful, but what about:

Today's stock market index => tomorrow's stock market index

Obviously, this would be a one-way conversion only. But I still would love it.

Best regards
Peter

      
HP-35s : Metric<->English and Conversions
Message #77 Posted by Karl Schneider on 2 June 2007, 7:55 p.m.,
in response to message #1 by Jeff O.

There's been quite a bit of discussion about the merits of SI/Metric and Imperial/English measurement -- too many to address individually.

John Gustaf Stebbins made an astute observation:

Quote:
Most countries that are all metric have had the advantage of not having significant industrial activity prior to adoption of SI or have needed to rebuild industry after war or catastrophe. Hopefully, we in the US will continue to struggle with mixed units well past my lifetime.

Without delving into much detail, I'll state the following:

  • SI/Metric is the language of science and most engineering, for good reason: It is a structured, consistent, system of units and measures. Imperial/English is more of a set thereof.

  • The main attribute of Imperial units is that they are generally are "right-sized" by design for practical use, and given short names with one or two syllables. Combining them can be a hassle, so decimal values are often employed.

  • The "ton" and "pound" adopted for metric use are certainly better than "megagram" and "half-kilogram", aren't they?

  • The Fahrenheit scale was probably designed for ambient temperature at the Earth's surface, and it remains better than Celsius for that purpose. There are 1.8 Fahrenheit degrees per Celsius degree, providing greater precision without a decimal digit. Moreover, triple-digit Fahrenheit readings (>= 100 degrees F) indicate hot conditions, but not impossibly so (as a triple-digit Celsius reading would indicate). Single-digit negative Fahrenheit readings indicate seriously cold conditions, rather than merely uncomfortably cold.

  • Celsius is better for aviation, because negative readings indicate the potential for icing.

  • The acre is generally a better-sized measure than the hectare for residential real estate.

  • The millimeter is a fine measure for short distances that are visually perceptible. It's better-suited for sizing wrenches than fractional inches (given to the nearest 1/32 inch). This is why an inch<->millimeter conversion might be more useful than inch<->centimeter -- particularly with the fraction-arithmetic planned for the HP-35s that is present in the HP-32SII and HP-33S.


So, back to Jeff O's original topic:

It's nice to have routine, simple conversions easily accessible on the keyboard with two keystrokes. However, the five pairs of metric<->Imperial measurements apparently intended for the HP-35s takes ten valuable keyboard positions. I certainly hope that the rectangular<->polar conversion that was displaced to make way for miles<->kilometers will be retained. To omit that would be a serious blunder.

-- KS

Edited: 2 June 2007, 8:50 p.m.

            
Re: HP-35s : Metric<->English and Conversions
Message #78 Posted by Walter B on 3 June 2007, 3:11 a.m.,
in response to message #77 by Karl Schneider

Some additions:

Quote:
The Fahrenheit scale was probably designed for ambient temperature at the Earth's surface, ...
AFAIK, Fahrenheit took the lowest temperature on earth known at his time as zero. Very arbitrary.
Quote:
... and it remains better than Celsius for that purpose. There are 1.8 Fahrenheit degrees per Celsius degree, providing greater precision without a decimal digit. Moreover, triple-digit Fahrenheit readings (>= 100 degrees F) indicate hot conditions, but not impossibly so (as a triple-digit Celsius reading would indicate). Single-digit negative Fahrenheit readings indicate seriously cold conditions, rather than merely uncomfortably cold.

Celsius is better for aviation, because negative readings indicate the potential for icing.


Depends on where you were raised. For me, nasty weather is below 10C, 20C is a comfortable ambient temperature, hot weather starts at 30C, hot surfaces >60C are dangerous to touch, boiling hot is 100C. Negative Celsius readings are also important for drivers. I enjoy skiing at -10C, but I have to take my warm clothes. Etc.

BTW, most people here are not scared by decimals. While it's perfectly legal to talk about "half a degree", these folks are not only able to divide by 2 (e.g. good and evil), but can handle divisions by 10 easily. So if they are really sick, they may "have 39.3C fever".

Quote:
The acre is generally a better-sized measure than the hectare for residential real estate.
Another nice example for personal bias. Here, only farmers own hectars of land. Residential real estate is measured in m², and 1,000m² is unaffordable in populated and/or attractive areas.
Quote:
The main attribute of Imperial units is that they are generally are "right-sized" by design for practical use, and given short names with one or two syllables. Combining them can be a hassle, so decimal values are often employed.

The "ton" and "pound" adopted for metric use are certainly better than "megagram" and "half-kilogram", aren't they?


See above. There are more of these "right-sized" weight units like a "Zentner" for 50kg or a "Doppelzentner" for 100kg. They may be used or not, in either case they fit nicely in the system. And nobody finds it difficult to talk about kilometers frequently, so 4 syllabels are no problem here.

Oh, and there are 2.5cm per Inch, providing greater precision without a decimal digit. d:-))

                  
Re: HP-35s : Metric<->English and Conversions
Message #79 Posted by Maximilian Hohmann on 3 June 2007, 1:18 p.m.,
in response to message #78 by Walter B

Hello!

Quote:
BTW, most people here are not scared by decimals.


On the contrary: I am really scared by fractions and mixed-units-measurements that are so common in the "imperial" unit system (like "1 3/16" bolts or 7-feet-8-inches body heights...)

My business (aviation) over the years has made the biggest mess of units that one can imagine. People die (maybe not every day, but every week or month) because of this nonsense. And all this despite the fact, that since 1965 the ICAO (International Civil Aviation Organization) does everything it can to ensure, that SI units are made mandatory worldwide. Must I say which country has so far undermined all these efforts?

Greetings, Max

                        
Re: HP-35s : Metric<->English and Conversions
Message #80 Posted by Karl Schneider on 3 June 2007, 5:39 p.m.,
in response to message #79 by Maximilian Hohmann

Hi, Max --

Quote:
On the contrary: I am really scared by fractions and mixed-units-measurements that are so common in the "imperial" unit system (like "1 3/16" bolts or 7-feet-8-inches body heights...)

"1 3/16" bolts

I agree. "30 mm" is much better.

7-feet-8-inches body heights

Wow! That's tall -- only men of the Dinka tribe in the Sudan and victims of giantism are generally that tall. 5'8" is more average for adults.

Quote:
And all this despite the fact, that since 1965 the ICAO (International Civil Aviation Organization) does everything it can to ensure, that SI units are made mandatory worldwide. Must I say which country has so far undermined all these efforts?

Hmm, mine, I guess... :-)

I assume that visibility measurements are given in hunderds of meters in European aviation, while in the US, fractional miles are still used. Are ceilings given in feet in Europe?

-- KS

                              
Re: HP-35s : Metric<->English and Conversions
Message #81 Posted by Walter B on 3 June 2007, 6:24 p.m.,
in response to message #80 by Karl Schneider

Aviatic measures are another retreat area of feet and the like. In Russia and former Soviet republics, however, aviation flies metric. Perhaps in Eastern Europe, too.

                              
Re: HP-35s : Metric<->English and Conversions
Message #82 Posted by Maximilian Hohmann on 4 June 2007, 8:29 a.m.,
in response to message #80 by Karl Schneider

Hi Karl,

Quote:
Hmm, mine, I guess... :-)

Not entirely wrong, your guess!

Quote:
I assume that visibility measurements are given in hunderds of meters in European aviation, while in the US, fractional miles are still used. Are ceilings given in feet in Europe?

Yes, horizontal visibilites are given in metres and kilometres throughout Europe (even in the UK, believe it or not!), while vertical visibilities are given in metres or feet depending on the country (France and former Eastern Block countries have metres, the rest uses feet, generally speaking, with some exceptions though...).
On the other hand, we have nothing on board to correlate the metric visibilities with: The airspeed indicators and distance readouts (apart from France again) display either nautical miles/knots (nautical miles per hour) or miles/mph (American statute miles per hour, even in the UK where the mile is slightly different from the US, I'm told). There are even airspeed indicators with two scales: One in knots, the other in mph. One airplane that I regularly fly has an airspeed indicator on the left side with a main scale in knots indicated and a subscale with knots true airspeed and a knots/mph idicator on the right hand side. Whenever you swap seats, you have to be very, very careful to get your speeds right, very dangerous nonsense indeed!

Greetings, Max

Edited: 4 June 2007, 8:31 a.m.

                  
Re: HP-35s : Metric<->English and Conversions
Message #83 Posted by Karl Schneider on 3 June 2007, 5:20 p.m.,
in response to message #78 by Walter B

Quote:
AFAIK, Fahrenheit took the lowest temperature on earth known at his time as zero. Very arbitrary.

It didn't seem very plausible to me that an 18th-century German scientist would have been unaware of climatic conditions (if not quantitative records) in Moscow and continental central Europe. So, I found the English- and German-language Wikipedia reference, which gives some unreferenced background:

http://en.wikipedia.org/wiki/Fahrenheit

http://de.wikipedia.org/wiki/Grad_Fahrenheit

Both articles reference the lowest temperature in Danzig/Gdansk in the winter of 1708-09, which may have established the zero-degree point. I believe that the lowest temperature recorded in Seattle, USA remains 0 degrees F (in January 1950), and there are many locations outside the tropics that have never experienced sub-zero Fahrenheit temperatures. (Incidentally, Seattle's all-time high was 99 deg F until several years ago.)

Just a clarification: Of course, I meant "ambient air temperature at the Earth's surface."

Quote:
BTW, most people here are not scared by decimals. While it's perfectly legal to talk about "half a degree", these folks are not only able to divide by 2 (e.g. good and evil), but can handle divisions by 10 easily.

The point, really, is to avoid half-degrees and to reserve negative and triple-digit readings as indicators of extreme conditions. My US-specification BMW's ambient temperature display shows integer Fahrenheit readings, and Celsius readings as "nn.0" or "nn.5".

Quote:
The acre is generally a better-sized measure than the hectare for residential real estate.

Another nice example for personal bias.

Here, only farmers own hectars of land.

Residential real estate is measured in m², and 1,000m² is unaffordable in populated and/or attractive areas.


It's pretty much the same in North America, except that larger lots are more obtainable outside those "populated and/or attractive areas". Even here, though, a one-acre (about 0.40469 hectare) urban or suburban lot is large.

Ah, but farmers own agricultural real estate.

If residential real estate is measured in m², I assume it's generally for a few ares of land directly underneath their own townhouses, not including a surrounding yard.

-- KS

Edited: 3 June 2007, 5:28 p.m.

                        
Re: HP-35s : Metric<->English and Conversions
Message #84 Posted by Walter B on 3 June 2007, 6:13 p.m.,
in response to message #83 by Karl Schneider

Karl,

one big point for you for the Fahrenheit-(hi)story! My version was what I remembered from school some 40 years ago. Anyway, zero degF remains very arbitrary.

Quote:
The point, really, is to avoid half-degrees and to reserve negative and triple-digit readings as indicators of extreme conditions. My US-specification BMW's ambient temperature display shows integer Fahrenheit readings, and Celsius readings as "nn.0" or "nn.5".
WHY avoid decimals?? And negative as well as triple digit readings are interpreted according to your environment and education as I pointed out above. The temperature display of your BMW is set the way you observed, because (1) it is sufficient for ice warning next to 0 C (every other indication is just for fun IMHO, meaning it allows to report your friends the morning temperature), (2) it reflects the precision of the sensor, (3) showing every tenth of a C would bring no benefit.
Quote:
If residential real estate is measured in m², I assume it's generally for a few ares of land directly underneath their own townhouses, not including a surrounding yard.
Lots may be as small as 200m² in towns, 400-600m² in suburbia nowadays, and bigger in the villages. A "surrounding yard" becomes possible with some 500m², depending on local regulations, and looks better the more area you own. As mentioned, the "ar" is hardly used.

Edited: 4 June 2007, 2:06 a.m.

                              
Re: HP-35s : Metric<->English and Conversions
Message #85 Posted by Bernard Rochlin on 6 June 2007, 2:16 a.m.,
in response to message #84 by Walter B

My GPS tells me no to use it as my sole means of navigation. In the same way my HP50g would not be the sole means of converting one system of measurement to another. I have a separate set of conversions in the outside chance that the HP 50g may be in error.Why is the United States not actively using the SI measurements

Edited: 6 June 2007, 2:18 a.m.

                                    
Re: HP-35s : Metric<->English and Conversions
Message #86 Posted by James M. Prange (Michigan) on 6 June 2007, 2:43 a.m.,
in response to message #85 by Bernard Rochlin

Quote:
Why is the United States not actively using the SI measurements
Maybe because most people in the U.S.A. simply don't want to use SI units for most measurements?

Regards,
James

      
Re: 35s - English Conversions
Message #87 Posted by Frank Rottgardt on 6 June 2007, 10:14 a.m.,
in response to message #1 by Jeff O.

The 33s has 40+ constants in a special menue. It shouldn´t be so complicated to give the 35s a decent build-in unit conversion function. You could have one single conversion key starting such a routine. As a first step the 35s asked you for the kind of unit you want to convert, e.g. "Volume, Length, Mass" etc. 2nd step is to refine the choice from a special submenue only containing units of the choosen kind, e.g. "kg, t, g, mg" if your choice was "mass". 3rd step is to enter the actual value, 4th step is to go through the same process for the target-unit.

            
Re: 35s - English Conversions
Message #88 Posted by Frank Rottgardt on 6 June 2007, 10:20 a.m.,
in response to message #87 by Frank Rottgardt

Of course you wouldn´t need to specify the kind of units for the target value, will say if you have choosen to convert "mass", specified "kg" then the 35s could automatically display the right choice of possible target units as "lbs, stone ...."

            
Re: 35s - English Conversions
Message #89 Posted by Patrice on 6 June 2007, 9:23 p.m.,
in response to message #87 by Frank Rottgardt

You are in RPN, so the first step is type the value, then go in the convertion menu cascade!

Patrice


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