Re: [ATM] how many errors can you spot in this passage on Foucault?

[Richard Ozer <rozer@pacbell.net>]

That's a good one...

I think the whole Mercury-Amalgam thing is wrong.  Mirror makers ... 
that's shaving mirror makers ... used to use Mercury Amalgam on the back 
of flat mirrors.  The heavy mirrors he's referring to are probably 
speculum rather than glass; and I'm not sure the main problem with size 
was the collapse of the telescope as much as it was the difficulty of 
casting and figuring large amounts of speculum.  Also, Foucaults's 
silvering technique is not widely used today; we of course use 
Aluminum... but then again that is going to be dependent on when the 
article was written.

RO

Guy Brandenburg wrote:
> Boys and girls,
>
> How many factual and conceptual errors can you spot in this passage, written about Leon Foucault by a writer who is often considered to be one of the major science/math popularists of the day? (The spelling mistakes, if any, are all mine.)
>
> "Foucault's great discovery in the area of astronomical instrumentation was a method of silvering the mirrors for reflecting telescopes. Reflecting telescopes that had been made up to that time used bulky, heavy mirrors. This limited the potential size of these telescopes because the weight of the mirror could collapse the telescope. Foucault inaugurated a new method of applying a layer of silver directly to the front of the telescope's mirror, rather than a mercury amalgam that was typically applied to the back of the mirror. Foucault's telescopes built this way were lighter and of better light-gathering quality than earlier telescopes, as evidenced by their use today, a century and a half after his time."
>
>
>
> Guy Brandenburg, Washington, DC
> My home page on astronomy, mathematics, education:
> http://home.earthlink.net/~gfbranden/GFB_Home_Page.html
> or else 
> http://tinyurl.com/r6fh2
>
> =============================
> "Education isn't rocket science. It's much, much harder."
> (Author unknown)
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