Re: [asa] mistake and slide rule

There seems to be a mathematics joke here that I just don't get.
But my bother-in-law, Ron, teaches college math.
Perhaps he will see the humor.

Or can someone just explain it?

-----Original Message-----
From: Iain Strachan [mailto:igd.strachan@gmail.com]
Sent: Monday, June 9, 2008 11:32 AM
To: 'Alexanian, Moorad'
Cc: 'George Cooper', asa@calvin.edu
Subject: Re: [asa] mistake and slide rule

A good test of the accuracy of early calculators is to compute e^pi - pi. It should come out as 20. If it comes out as 19.999... you probably have a poor floating point handler in the calculator.... :-)

See the cartoon on my blogsite:

http://iainstrachan.blogspot.com/2008/05/geek-joke.html

Iain

On Mon, Jun 9, 2008 at 3:28 PM, Alexanian, Moorad <alexanian@uncw.edu> wrote:
I still have my bamboo and ivory Post slide rule. I recall the trill when, with my new HP calculator made in the USA and which I still have, was able to calculate pi to the pi power. What a trill! At the University of Rhode Island, our engineering students used to carry their slide rules hanging on their belts like gun holsters. Those where the days!

Moorad

________________________________

From: asa-owner@lists.calvin.edu on behalf of George Cooper
Sent: Mon 6/9/2008 10:02 AM
To: asa@calvin.edu
Subject: RE: [asa] mistake and slide rule

I witnessed the transition from slide rules to calculator in the early 70's.
As a freshman, we were required to take a slid rule class. By the time I
was a junior, the HP was already out but it was > $400 then, and the TI was
coming out < $ 170 (no trig. Functions, however).

Things came to head once more of us started using them during tests -- they
were soon outlawed during tests in some classes. Our M.E. dep't head (since
1957), Clifford Simmang, challenged all of us in his thermo. class to a
duel: his slide rule against our calculator. I thought he was joking, but
he wasn't. After we cleaned his plow, he chuckled and confessed engineers
were often overly attached to their slide rule. He then told of us a fire
that had broken-out in an industrial plant where he worked. He said while
they were rushing to the incident, a fellow engineer was late to the fire
because he had elected to go back for his slide rule.

"Coope"

-----Original Message-----
From: asa-owner@lists.calvin.edu [mailto:asa-owner@lists.calvin.edu] On
Behalf Of George Murphy
Sent: Monday, June 09, 2008 7:02 AM
To: Dave Wallace; ASA
Subject: Re: [asa] mistake

As a physicist I never had a problem with slide rules. Still, doing some
arithmetic by hand - or in your head - is a way to stay sharp mentally. &
trying to add on a slide rule doesn't work well.

I still remember ~30 years ago, when calculators were becoming common & I
was teaching general physics. I was talking a student through a problem &
as we got to the conclusion I said rhetorically, "OK, now what's 6 times 3?"

& she dutifully got out her calculator ...

One other problem with calculators - & for that slide rules - is that
students don't have much feel for what logarithms are. If you actually had
to solve multiplication problems by looking up logs & adding them you have
more of a sense for them that if you know them just as an abstract function.

Shalom
George
http://web.raex.com/%7Egmurphy/

----- Original Message -----
From: "Dave Wallace" <wmdavid.wallace@gmail.com>
To: "ASA" <asa@calvin.edu>
Sent: Sunday, June 08, 2008 9:53 PM
Subject: Re: [asa] mistake

> Lawrence Johnston wrote:
>> Welcome back, you old curmudgeon. I am glad to hear the latest on energy

>> supplies. Please stick around, we need you. God bless.
>>
>> Larry Johnston
>> (a 90-year old curmudgeon)
>>
>> =========================================================== Lawrence
>> H. Johnston home: 917 E. 8th st. professor of
>> physics, emeritus Moscow, Id 83843 University of Idaho
>> (208) 882-2765 Fellow of the American Physical Society
>> http://www.uidaho.edu/%7Ejohnston/HOMEPA%7E1.HTM ==============
>> ------------------------------------------------------------------
>>
>> From: "Glenn Morton" <glennmorton@entouch.net>
>> To: <asa@calvin.edu>
>> Subject: [asa] mistake
>> Date sent: Sun, 8 Jun 2008 14:06:47 -0500
>>
>>
>>> Sitting in Church today my thoughts wandered from the preacher and I
>>> realised when I calculated the life time of a 200 year nuclear fuel
>>> supply
>>> if we use nuclear to replace oil, it isn't an 18 year supply. To replace

>>> oil
>>> with nuclear requires 6 x the number of nukes we have today. So, it
>>> should
>>> be a 33 year lifetime.
>>>
>>> Wondering why I did it, I think I stopped the math when I decided that
>>> 6
>>> goes into 200---18 and when it should be 3x6=18 subtract 18 from 20,
>>> equals
>>> 2, drop the zero, 6 goes into 20 3 times. ..So, my 3rd grade math is
>>> lousy, and this is clearly an example where a mistake doesn't prove that

>>> I
>>> know nothing on any other topic, although I might be evidence that I
>>> need to
>>> return to the 3rd grade for a refresher course. No anger here.
>>>
>>>
>>>
> I am of the same opinion as the other posts I have seen so far, we need a
> dose of reality now and then. Winston Churchill was a crusty old
> curmudgeon, but I find many of his writings worthwhile and I don't think
> you even are in the same league as Winston in terms of crustiness.
>
> Don't feel too bad as lots of us have the same kind of problem with
> arithmetic, sometimes to check myself I do rough calcs two ways and
> compare the answer to see if the order of magniture is even right.
>
> By the way I barely finished grade 1 to 4 arithmetic and my teacher
> (singular) told my parents I was close to unteachable and would not finish

> high school. Then in grade 5 with a different teacher, I started getting
> close to perfect scores as we started doing problems and not solving
> boring arithmetic examples over and over. Sure people should know basic
> arithmetic and not rely on calculators for everything as some children
> coming out of our schools here seem to. But one can always look in the
> back of the book for 11 times 12 or quickly figure it out mentally by
> multiplying 10 times 12 and adding 12 but that does not work in a test
> that is a fast drill of the tables. On another tack, I still wish that
> I had my old K&E log log slide rule as it was a real good way to do back
> of the envelope calcs, especially proportions and of course it did not
> produce answers good to 64 bit, ie double precision floating point
> (sarcasm). Somehow precise computer answers carry way too much weight. I

> know, I know, only dumb engineers use slide rules, at least that was what
> the physics and math majors told us when I went to University of Waterloo.
>
> Dave W 68 this year and counting for a while yet I hope
>
>
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