On Mon, 26 Feb 2018 11:44:07 +0000, Chris J Dixon
wrote:

Jim Lesurf wrote:

I was wondering how many professional engineers or scientists do so. e.g.
use tools like MathCad, etc, whilst having no real idea how they work or of
the commands they gave are the correct/relevant ones and can be expected to
give an appropriate 'answer'. More than once I've found (professional)
people engaging in GIGO.

Quite! It is clear that if you work to the appropriate Quality
Standards that you should be able to demonstrate that you have
verified that the calculations you perform give correct results,
and that input conditions and outputs are recorded auditably.

I recall one situation where a train performance program was
being used to work out the rating for a works locomotive, and it
was realised that altering the gradient of the tunnel in which it
was to be used had no impact on the output.

The relative ease of producing a spreadsheet can lead to
automatic belief in its results, and if the parameters keep being
altered, how easy is it to back track later to find where the
numbers came from?

Chris

I make a lot of use of Mathcad. But part of the process is exercising
it with corner cases and variable sweeps to make sure that everything
it does makes sense in terms of the model.

Where possible I will always use units as they provide inbuilt
dimensional analysis. If an answer that is supposed to be in Hz
insists that it is kg/foot, I know I need to do a bit of checking.

d

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In article , Don Pearce
wrote:

Where possible I will always use units as they provide inbuilt
dimensional analysis. If an answer that is supposed to be in Hz insists
that it is kg/foot, I know I need to do a bit of checking.

Sadly, I doubt they teach any dimensional analysis in schools any more.

Maybe this is why we've had generations of theoretical physicists who do
all their calculations 'normalised' so that every physical constant is '1'.
8-]

Makes trying to work out *real* answers a bit of a challenge.

Jim

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On 25/02/2018 09:21, Jim Lesurf wrote:
In article , RJH
wrote:
From a quick look, I'd have hoped so. I think (even) I can follow most
of the calculations, even if I don't understand the 'why' - say, the
basis of assumptions.

Incidentally, did many of your students enrol on non-honours degrees?

I lectured at St Andrews and Scotland runs a different educational system
to England. So I need to upack things a little to answer that.

Here we run a *four year* first degree course. This is because the
established arrangement in Scotland has been for school students to do a
*one year* 'highers' not a two-year 'A level'. So they come in a year
younger.

Again, conventionally here they take rather more than 3 or 4 subjects for
their 'highers' so have a broader base, with less depth.

To accomodate that the entry to 1st year is quite wide. And for those who
have done 'A levels' or equivalent there is the option to enter direct into
'second year'.


I didn't realise that - I know some students from England who've studied
in Scotland. Pretty sure they did 4 years - I'd guess especially good A
levels might have got them a pass to year 2. Dread to think how the
loans system operates for English students.

So the first two years (nominally) are not 'honours', but a wider class.
This then narrows down to two 'honours' years for the students who chose to
do physical sciences. They then can pick what courses they do.

My own honours courses would be given once every *two* years. So some
students did them in their 1st Hons year, others in 2nd Hons. This meant
more courses could be offerred overall.

Only a tiny number took a 'pass' degree. Most went though and got an
Honours degree of some type.


In my experience, English students don't have any say when they start -
it's honours or nothing. But like the Scottish system they can decide to
drop the honours - usually by not taking the dissertation. I've known
that happen once - over a few thousand students. Most of the time a
non-honours is a result of some under-performance along the line, and is
awarded at the end once the credit tally is known.

I think the bulk of the maths in what I taught would be easy enough for
most of them. But the key is in what you said. Understanding the 'why and
how' can be harder because this is where people need to twig the concepts
from which the maths can flow and give concrete answers to specific
questions.


Yep. Must say I find mathematical (and a lot of natural science) theory
very difficult to reconcile. I worked with a quantitative economist for
a while, and was ground down by the liberal use of 'nominal' and
'equals'. Things like trigonometry squares/triangles itself in my little
brain, but much more than that and I'm at sea :-)

--
Cheers, Rob

In article , RJH
wrote:
On 25/02/2018 09:21, Jim Lesurf wrote:
In article , RJH
wrote:



In my experience, English students don't have any say when they start -
it's honours or nothing. But like the Scottish system they can decide to
drop the honours - usually by not taking the dissertation. I've known
that happen once - over a few thousand students. Most of the time a
non-honours is a result of some under-performance along the line, and is
awarded at the end once the credit tally is known.

Similar here. In effect low marks may end up with a 'pass' or a 'fail'. But
the norm will be a Honours degree.

The real killer here for many years was a Uni reg that the student had to
pass *every* hons exam. Once they went in to the hall, sat down, and
started, they had to pass. Failing to do so meant they then could proceed
no further. No retakes, no progess. End of!

This was a mad regulation. So in reality staff sometimes fudged or turned a
blind eye. We'd decide off-the-record in some cases that the student had
been ill and not turned up, or similar.

Fortunately, that reg got changed.

In contrast, at QMC when I did my 1st degree you could take up to 8 courses
/ exams per year and only needed to pass 6 per year to proceed. If you got
fewer passes you might still proceed, but unless your total was sufficient
after 3 years you would get a 'pass' degree. Much more flexible as you
could also re-sit exams for courses, sometimes without having to go though
them again. Made dealing with illnesses, family/personal problems, etc,
much easier.

I think the bulk of the maths in what I taught would be easy enough
for most of them. But the key is in what you said. Understanding the
'why and how' can be harder because this is where people need to twig
the concepts from which the maths can flow and give concrete answers
to specific questions.


Yep. Must say I find mathematical (and a lot of natural science) theory
very difficult to reconcile. I worked with a quantitative economist for
a while, and was ground down by the liberal use of 'nominal' and
'equals'. Things like trigonometry squares/triangles itself in my little
brain, but much more than that and I'm at sea :-)

Maths is a great tool, but a lousy master. It works *when* you understand
the relevance of the mathematical arguments. Otherwise it can be a way to
spin bafflegab.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics https://www.st-andrews.ac.uk/~www_pa...o/electron.htm
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