Doh! NS polarization, not EW!

[William Beaty <billb@ESKIMO.COM>]

On Thu, 17 Jun 1999, Mark Kinsler wrote:
> billb wrote:
> > This zone forms a huge band which arches across the sky at 90
> > degrees from the location of the sun.  E.g. at sundown this band of
> > polarization sweeps from the western horizon, up to the zenith, then down
> > to the eastern horizon.  The sky in this band is fairly dark blue, while
> > the sky towards the sun and opposite the sun is much lighter and
> > unpolarized.
>
> All of which proves that astronomy is awfully tough to figure out, at
> least for me.  I'll try it with a pair of sunglasses sometime.

Actually this is an instance of the "textbook misconception" syndrome,
where the student reads a bad or wrong explaination, becomes befuddled,
and blames the subject area rather than blaming the explainer.  In other
words:

RATS RATS RATS!  I'm TOTALLY screwed up.  That band of dark blue,
polarized sky runs north to south.  Someone on PHYS-L caught my error.  I
was driving to Canada at the time, staring due North while tilting my
head.  The polarized band was right where it's supposed to be.  (But the
sun sets in the south, right? Doh!  )

If the sun is setting in the west, then there is unpolarized sky near the
sun, unpolarized sky in the region *opposite* the sun, and polarized sky
everywhere else.  If the sky is a sphere, then the solar and antisolar
regions are the "poles", and the region with polarized-light forms a broad
"equator".

(I guess people should always practice critical thought in regards to the
pronouncements of experts such as... myself.)




> When tempered glass finally does break (a hammer and punch will do it)
> it'll break into zillions of roundish pieces.  Glass blowers in Europe
> amuse each other by making glass globs and tempering them by plunging them
> into water. These are resistant to hammer blows, but will blow up with a
> tremendous noise if the end is pinched off with a pair of pliers.  I
> assume the shattering produces harmless pieces, because the standard
> procedure is to wait until a collegue is bent over with some tricky job
> near the furnace, at which time the glob is pushed down the back of his
> pants and the end snapped off.

I once tried making these so-called "Prince Rupert's Drops" by melting a
glass rod and dripping the droplets into a bucket of water.  Almost all of
them shattered within a minute, but I did see one that lasted for awhile.
When I broke the narrow neck (hard to do), the rest of the droplets went
"kkkkkkk" and fell to pieces.


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William J. Beaty                                  SCIENCE HOBBYIST website
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