Date: Thu, 30 Aug 2001 20:05:23 -0400

Author: "Robert W. Harris"

Subject: Re: Color mixing apparatus

Post:

Good idea. At the end the kids could eat the jello. -- But the demo
would have to be done rapidly or the heat of the overhead would liquefy the
jello.

Br. Robert W. Harris
Catholic Memorial School
http://www.CatholicMemorial.org
http://www.CMphysics.org
----- Original Message -----
From: Machele Bailey
To:
Sent: Thursday, August 30, 2001 10:13 AM
Subject: Re: Color mixing apparatus


> Perhaps jello would be a viable alternative to the liquid?
>
> "Robert W. Harris" wrote:
>
> > Poor man's version:
> > 3 petri dishes with water and food coloring
> > 3 overhead projectors with cardboard covering the each stage, each
cardboard
> > has circular cutout to receive one petri dish.
> > Aim projectors at a screen. Push/twist them so the colors overlap. It
> > works, and is nearly free, assuming you have overheads and petri dishes
in
> > the school.
> >
> > Br. Robert W. Harris
> > Catholic Memorial School
> > http://www.CatholicMemorial.org
> > http://www.CMphysics.org
> >
> > ----- Original Message -----
> > From: Earl Dolnick
> > To:
> > Sent: Wednesday, August 29, 2001 4:20 PM
> > Subject: Re: Color mixing apparatus
> >
> > > We made one out of 3 old slide projectors. I bought 3 dichoric color
> > filters
> > > from Edmund that are coated on glass, and 2 inches square. They fit
> > exactly
> > > in place of a 35MM slide. The projectors are mounted on a board that
can
> > be
> > > tilted with a lab jack. Each projector has a dimmer, and the images
> > overlap
> > > on the screen. The filters are excellent. We turn on the colors one at
a
> > > time, and it is still striking to me that when the red and green
overlap,
> > > the intersection is bright yellow. And, where all the colors overlap,
the
> > > screen is white. Red is usually brightest, and must be turned down
> > relative
> > > to the green and blue. Total cost was under $200. The hardest part was
> > > finding old bulbs for the projectors.
> > >
> > > Cheers, Earl D.
> > >
> > >
> > > Earl Dolnick
> > > UCSD Physics
> > > 858 534 8154
> > > edolnick@ucsd.edu
> > > ----- Original Message -----
> > > From: "David Kardelis"
> > > To: "Tap-L (E-mail)"
> > > Sent: Wednesday, August 29, 2001 12:55 PM
> > > Subject: Color mixing apparatus
> > >
> > >
> > > > Anyone have a recommendation on a color mixing apparatus.
> > > >
> > > > The Leybold one I had wore out, the rubber mounts that held the
mirrors
> > > > distentigrated after many years. They failed and the mirrors fell
off
> > and
> > > > are now cracked.
> > > >
> > > > I have tried colored spot lights but the effects are only so-so.
> > > >
> > > >
> > > > Thanks dave
> > > >
> > > >
> > >
>
> --
> Machele Bailey-----Lab Manager-----Wake Forest University
>
> -----"Nothing shocks me. I'm a scientist." - Indiana Jones-----
>

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