Re: Touch the SPring

From: Barry and Janet (
Date: Wed Aug 14 2002 - 22:46:42 PDT

Hi, Nina - This afternoon I checked a little further on the discussion page
and found that some people had obtained a spherical mirror from VWR
INTERNATIONAL which I thinkwas in your links, but I got into a strange place
the first time. When I found out that someone had obtained one there, I
looked harder and found it.

I checked your link about spherical vs. parabolic and it looks like i should
have ordered the parabolic mirror. I guess you can't have too many mirrors.


On-line Snack discussion wrote:

> Arbor Scientific which is linked from our
> supplies page, offers the following:
> "Product ID: P2-7150-02 Category: No Category Concave Mirror
> Description: These extra-large parabolic mirrors make demonstrating
> optical principles a snap. Each silver-backed, non-aluminized mirror
> measures 24" in diameter and is supplied with an aluminum frame, mounting
> bracket, and base. Price: $100.00"
> Of course, that's larger than 40cm and, although smaller ones are
> available, you are right that the 40cm size does not seem to be offered
> anymore. You might consider getting a smaller mirror and doing the
> experiment with something smaller than a light bulb. A parabolic mirror
> is a concave mirror designed so that it won't produce spherical
> aberration. For an explanation see:
> There are many
> other web sites that discuss this as well.
> Nina Thayer
> Snacktalk Moderator
> > I'm looking for a mirror for the "touch the spring" project. I can't
> > find one that's as big as 40 cm. I checked all of the links that you
> > have for materials. The largest is 10 cm. I did find a large parabolic
> > mirror, but I think that when you say concave mirror you mean a
> > spherical concave mirror. Is that correct? Am I looking for a
> > spherical mirror? Actually looking in the book, I see a reference to
> > both spherical and parabolic mirrors. Will both work?
> >
> >

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