Re: [ATM] 5th/6th Grade Class ATM Presentation

[vorblesnak@peak.org]

May 11th is the program at Toledo Elementary.  I gave them a pie plate
mirror and secondary and they are going to make a scope.  These are sixth
graders.  The night of the 11th we are having a star party to test the
scope and learn some sky.

The day of the 11th we will explorer types of telescopes and how they are
made.  Maybe grind on some glass.  I hadn't though of a pin hole projector
but that sounds good.  We will talk about constellations and how they were
named. (365 Starry Nights).  A great thing to do is get a star chart and
have the kids find their own constellations, draw them and name them. 
Maybe a story about the character they create.  Show them the math for
figuring the sagitta and then bring it back to their level, how many
sheets of paper would measure that depth?  How may pennies?

I agree with Mel, let them get their hands dirty.

David Davis
Toledo, OR 97391


>> 1)  I'm sure that a little bit of the discussion will be in describing
>> how a newtonian reflector telescope focuses, magnifies, gathers light, >
>
>
> Yes, ideas.  Absolutely don't do a presentation on a projector; don't do a
> passive explanation where you talk through some model in your hands.
>
> Kids gotta learn that this is about discovery on every level that they can
> imagine.
>
> Get ahold of some raw materials (cheap big lenses, cardboard tubes,
> binocular eyepieces) and whatnot, break the kids up into small groups, and
> give them 15 minutes to figure out how to make a magnifier of distant
> objects (a telescope).  Do solar pinhole projectors with some cardboard
> boxes and aluminum foil: let them investigate differing solar diameters
> and
> why that could be.  That's a telescope too!  Oh, and see if anyone
> mentions
> any sunspots.  Then talk about the scale of the Earth vis-?-vis a sunspot.
> Ask how far away the Sun is if a sunspot is bigger than the Earth's
> diameter.  Ask them to figure out as a class why stars cannot be seen
> during
> the daytime.  Ask them why the sky is dark at night.  Give them something
> to
> see that night with their unaided eye: Moon, Venus, Sirius, Big Dipper,
> whatever.
>
> Mel Bartels
>
>
>
>
> ------------------------------
>
> Message: 20
> Date: Wed, 25 Apr 2007 22:26:07 -0400
> From: "Jerry" <wa4guu@verizon.net>
> Subject: Re: [ATM] Persistent turned-up-edge in mirror
> To: "'Mike Lockwood'" <melockwo@uiuc.edu>,	<atm@atmlist.net>
> Message-ID: <006601c787aa$3f84db10$0100a8c0@D85SJB21>
> Content-Type: text/plain; charset=US-ASCII
>
> .......
>
> Well anyway... That is why I made no suggestion about methods for fixing
> TUE. (I cut out all of my reasons why for brevity and besides, who cares
> why
> anyway?) Almost anything will fix it. Just about the only thing that won't
> fix it is short centered strokes. That is how you make it. It is proven
> that
> in the hands of most all, short center over center strokes makes an oblate
> with a TDE. I suspect (emphasis on that word suspect) there is a TDE on
> the
> outside of that turned up outer zone. But until it is fully polished, what
> does it matter? Not much.
>
> How would I fix it?  In this case for sure, I would just quit making it.
>
> If my normal polishing stroke produced with certainty something deviating
> from a sphere more than just slightly oblate (or slightly prolate) I would
> consider the stroke to be "wrong". I would adjust the stroke length and
> side
> until I found a combination that produced something reasonably spherical.
> A
> TDE almost always comes with that oblate. But on a first mirror no big
> deal.
>
> Once I learned what makes a reasonably spherical surface, that would be my
> standard polishing stroke and I wouldn't spend much time looking at the
> shape until polishing is complete.
>
> I cut some stuff out here too.
>
> I read that chapter in ATM Jim pointed to. Read it before, more than once.
> There are some things in those books (ATM 1, 2, 3 and Texereau and others
> too) that I disagree with. I think some things are just plain wrong. Don't
> think it could be me. I think every technique that I use and everything I
> believe to be true about mirror making is in them too. There is nothing
> new
> under the Sun.
>
> These books are always a good read when pulling one off the shelf. Reading
> those books would provide many ideas about TUE and all those other things.
> Experience with those ideas is attained the old fashioned way, through
> experience.
>
> As for using the fingers for figuring, (I've done it and I cut some more
> drivel out here). Whether I would suggest someone try it or not, or what I
> think the results might be was in what I cut out. If you don't have the
> experience you only have hearsay.
>
> Jerry
>
>
> Jim Burrows wrote:
>> Hey, whole-mirror strokes aren't the way to attack TUE!  Go around the
>> edge with a small tool (or your thumb).  "Three revolutions of the
>> mirror is enough of this without testing to be sure the action is
>> where it is wanted and not producing a ditch."  A.T.M. 2, p. 43, 1946.
>
>
> Mike Lockwood wrote:
>
> I must (respectfully) disagree with that 60-year-old advice.
>
> First, relating to the previous question on the list, if someone has
> to ask how to fix a TUE, they are not ready to use their finger as a
> polishing tool
>
>
>
> ------------------------------
>
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>
> End of ATM Digest, Vol 40, Issue 25
> ***********************************
>




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