Date: Mon, 29 Aug 2011 20:10:35

Author: B R Sitaram

Subject: Re: Batteries & Bulbs Circuits (Was Physics by Inquiry)

Post:

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Hi,

The reference to "Light and Optics Module" reminds of something that I had
done some years ago and would like to repeat. I took two sheets of acrylic
sheet and put them in a vice. As I increased the pressure on the vice, the
two sheets pulled apart from each other and formed two surfaces of a convex
lens. I then covered the bottom of the lens with another sheet of acrylic,
making a lens shaped container and filled it with sugar solution (higher mu
than pure water). I then had a (reasonably) convex lens (curved in the
horizontal, plane in the vertical) of about 50 cm focal length and an
aperture of about 30 cm. I then used threads (attached to pins) to indicate
rays of light. This formed an excellent exhibit to show that most rays (i.e.
the paraxial ones) emanating from a point came to a focus at a single point;
many books only show 2 or 3 rays, with the result that many students believe
that there are only those 2 or 3 rays!

Of course, if I were to do it again, I would use a mould to ensure that the
acrylic would be exactly convex in shape, and perhaps use a high-mu liquid
inside. I am trying to learn how to mould acrylic now!

Suggestions anyone?

Sitaram

On 29 August 2011 19:33, wrote:

> Does any of this group remember the McGraw-Hill publication "Batteries and
> Bulbs"?
> If so, you may find it exceedingly useful when implementing many of the PER
> exercises (many are exactly the same, probably because some early PER
> researchers were on the original NSF sponsored projects).
>
> From the 60's to the early 70's NSF sponsored the publication of about 80
> works under the banner "ESS" for Elementary Science Study. Google it for
> more info.
>
> The next best in the series involved "Light and Optics" (which had ray
> sources with prisms, lenses, mirrors) and another involved "Waves and
> Pendulums" (which had SHM using masses on springs and pendula hung from
> string taped to door openings). And that's just 3 of the excellent resource
> materials produced under the ESS/NSF banner.
>
> My colleague, Jack Turner, and I used these resources in setting up summer
> camps for grade school children and teachers when the state of Texas adopted
> required hands-on science in grades K-12 back in 1985 (Texas Public Law
> 21-101).
>
> Get your hands on a copy if you are into elementary level hands-on
> activities in science (at any grade level). My guess is that they are no
> longer copyright protected.
>
> Enjoy, Karl
>
>


--
Take a look at our website for more information
about the exciting work we do and to download great stuff! Click
hereto see our toys and kits!

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Hi,The reference to "Light and Optics Module" reminds of =
something that I had done some years ago and would like to repeat. I took t=
wo sheets of acrylic sheet and put them in a vice. As I increased the press=
ure on the vice, the two sheets pulled apart from each other and formed two=
surfaces of a convex lens. I then covered the bottom of the lens with anot=
her sheet of acrylic, making a lens shaped container and filled it with sug=
ar solution (higher mu than pure water). I then had a (reasonably) convex l=
ens (curved in the horizontal, plane in the vertical) of about 50 cm focal =
length and an aperture of about 30 cm. I then used threads (attached to pin=
s) to indicate rays of light. This formed an excellent exhibit to show that=
most rays (i.e. the paraxial ones) emanating from a point came to a focus =
at a single point; many books only show 2 or 3 rays, with the result that m=
any students believe that there are only those 2 or 3 rays!
Of course, if I were to do it again, I would use a mould to ensure that=
the acrylic would be exactly convex in shape, and perhaps use a high-mu li=
quid inside. I am trying to learn how to mould acrylic now!Suggesti=
ons anyone?
SitaramOn 29 August 2011 19:33, ics.utexas.edu> wrote:
Does any of this group remember the McGraw-Hill publication "Batteries=
and Bulbs"?
If so, you may find it exceedingly useful when implementing many of the PER=
exercises (many are exactly the same, probably because some early PER rese=
archers were on the original NSF sponsored projects).

From the 60's to the early 70's NSF sponsored the publication of ab=
out 80 works under the banner "ESS" for Elementary Science Study.=
Google it for more info.

The next best in the series involved "Light and Optics" (which ha=
d ray sources with prisms, lenses, mirrors) and another involved "Wave=
s and Pendulums" (which had SHM using masses on springs and pendula hu=
ng from string taped to door openings). =A0And that's just 3 of the exc=
ellent resource materials produced under the ESS/NSF banner.


My colleague, Jack Turner, and I used these resources in setting up summer =
camps for grade school children and teachers when the state of Texas adopte=
d required hands-on science in grades K-12 back in 1985 (Texas Public Law 2=
1-101).


Get your hands on a copy if you are into elementary level hands-on activiti=
es in science (at any grade level). My guess is that they are no longer cop=
yright protected.

Enjoy, Karl

-- Take a look at our website for more i=
nformation about the exciting work we do and to download great stuff! Click=
here to see our t=
oys and kits!


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