What is different with Python ?

[Claudio Grondi]

> Yes, both the sun and the moon have gravitational fields which affect
> tides.  But the moon's gravitational field is much stronger than the
sun's,
> so as a first-order approximation, we can ignore the sun.

Here we are experiencing further small lie which found its way
into a text written by an author probably not aware, that he is
creating it.
I have picked it out, not because I am so biased towards
the very detail, but because it is a good example of how hard
it is to discuss without creating small lies one after another.

The school books are filled with statements similar to the above
causing endless confusion and misunderstandings.

"the moon's gravitational field is much stronger than the sun's"
...
Sure it is the opposite, i.e. the gravitational field of the sun is
much stronger than that of the moon. What was intended to
state is probably, that the gravitational force caused by attraction
of the masses of earth and the sun applied to earth is lower
than the gravitational force caused by attraction of the masses
of earth and the moon (applied to earth).
I am sure, that if someone will analyse the statement above
deep enough he will find some more small lies originated
by the temptation to keep any statements short and simple
without giving a precise definition of all assumptions
required to be known in order to understand it right.

What leads to confusion is also the explanation that the water
of the oceans is attracted by the moon. It is only half of the
true. The another half is, that the moon is attracted by the
water of the oceans. It is very interesting, that in the minds
of many people the gravitational force acts only on one body.
Many think I am stupid, when I try to insist that the gravitational
force a human body exerts on earth is the same as that which
the earth exerts on a human body.
"the human body is so small, so the gravitational force it exerts
on earth can be neglected compared to the gravitational force
the earth exerts on the human body" is the explanation.

The problem of science is, that for communication of its findings
it has to use the same language which is used also for many other
purposes. The problem of text writers is, that it is so convienient
to use shortcuts to what one thinks, but has just forgotten to mention
before. It is also common to expresses own thoughts in an
inappropriate way because at the moment the right words are just
not there.

Hope this above has cleared away all what was clear before ;/)

What has it all to do with Python? To be not fully off-topic, I
suggest here,  that it is much easier to discuss programming
related matters (especially in case of Python :-) or mathematics
than any other subjects related to nature, because programming is
_so easy_ compared to what is going on in the "real world".
I see the reason for that in the fact, that programming is based
on ideas and rules developed by humans themselves, so it is
relatively easy to test and proove if statements are right or not.
Exception is when the source code is hidden like the rules
directing the behaviour of our Universe, what sure shouldn't be
interpreted, that people hiding source code behave more
like The Creator than others making it public  ;/)

Claudio


"Roy Smith" <roy at panix.com> schrieb im Newsbeitrag
news:roy-568484.09073015062005 at reader1.panix.com...
> Steven D'Aprano <steve at REMOVEMEcyber.com.au> wrote:
>
> > Roy Smith wrote:
> > > Steven D'Aprano <steve at REMOVEMEcyber.com.au> wrote:
> > >
> > > >High and low tides aren't caused by the moon.
> > >
> > >
> > > They're not???
> >
> > Nope. They are mostly caused by the continents. If the
> > Earth was completely covered by ocean, the difference
> > between high and low tide would be about 10-14 inches.
>
> Yeah, I know about all that stuff.  But, let's explore this from a
teaching
> point of view.
>
> > The true situation is that tides are caused by the
> > interaction of the gravitational fields of the sun, the
> > moon and the Earth, the rotation of the Earth, the
> > physical properties of water, its salinity, the depth,
> > shape and composition of the coast and shoreline, the
> > prevailing ocean currents, vibrationary modes of the
> > ocean (including up to 300 minor harmonics), ocean
> > storms, and even the wind.
>
> That's a lot of detail to absorb, and is appropriate for a college-level
> course taken by oceanography majors.  The key to teaching something is to
> strip away all the details and try to get down to one nugget of truth with
> which you can lay a foundation upon which further learning can happen.
>
> Yes, both the sun and the moon have gravitational fields which affect
> tides.  But the moon's gravitational field is much stronger than the
sun's,
> so as a first-order approximation, we can ignore the sun.
>
> And, yes, there's a huge amplifying effect caused by coastline shape and
> resonant frequencies of the ocean basins, but if you took away the moon
> (remember, we're ignoring the sun for now), there would be no tides at
all.
> If you took away all the continents, there would still be tides, they
would
> just be a lot less (and nobody would notice them!).
>
> And, yes, wind affects tide.  I live at the western tip of Long Island
> Sound.  If the wind is blowing hard along the axis of the Sound for a
solid
> day or two, I can see that it has a drastic effect on the tides.
>
> This says to me that "The tides are created by the moon, amplified by the
> shapes of the land masses, and altered by the wind".
>
> Sure, "the moon causes the tides" is not the whole picture, and from a
> quantitative point of view, may not even be the major player, but from a
> basic "How do I explain this physical process to a 6th grade child in a
way
> that's both easy to understand and fundamentally correct", I think "the
> moon causes the tides" is the only reasonable explanation.  Once that
basic
> idea is planted, all the other stuff can get layered on top to improve the
> understanding of how tides work.
>
> So, to try and bring this back to the original point of this thread, which
> is that Python is a better first language than C, let's think of the moon
> as the "algorithms, data structures, and flow control" fundamentals of
> programming, and memory management as the continents and ocean basins.
> What you want to teach somebody on day one is the fundamentals.  Sure,
> there are cases where poor memory management can degrade performance to
the
> point where it swamps all other effects, but it's still not the
fundamental
> thing you're trying to teach to a new CS student.