Re: [Phys-l] index of refraction

["Paul Lulai" <plulai@stanthony.k12.mn.us>]

For each liquid, they could measure multiple angles, plot sin(theta-i) vs sin(theta-r), From the plot they could determine if y-intercept or slopes have any meaning.  This would have a better influence if different groups measured these angles for different materials (or each group did this for multiple materials).

That would make it a fairly productive lab.  Additionally, they could calculate % difference btn their values and the 'accepted' values.  

That would be my h.s. approach.  Curious if there is a more high-falutin college or industrial approach.

Paul Lulai
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-----Original Message-----
From: phys-l-bounces@carnot.physics.buffalo.edu [mailto:phys-l-bounces@carnot.physics.buffalo.edu] On Behalf Of John Clement
Sent: Monday, May 11, 2009 12:39 PM
To: marx@phy.ilstu.edu; 'Forum for Physics Educators'
Subject: Re: [Phys-l] index of refraction

It would be very close to water because it is not a very concentrated
solution.  Similarly many other household chemicals such as vinegar are
solutions with mainly water.

The advice about the problems with bleach is very good.  Soda might be
difficult because the bubbles will disrupt the light.  You could have the
students make saturated solutions of salt or sugar.  I suspect the index
will also be very close to that of water.

Of course one must ask what is the purpose of the lab, and what are students
learning from the lab.  Verification labs do not really help students much.
They are mainly practice.  What can be discovered from this lab? Guided
inquiry labs have been shown to improve student cognition, and the retention
of concepts.

John M. Clement
Houston, TX


> The odors from bleech are quite strong and may affect some students.  I
> would not use it.  Also, if it
> spills on clothing, it may damage it.  However, if you want to know the
> index, measure it and don't rely
> on online tables.
>
>
> On 11 May 2009 at 12:48, Anthony Lapinski wrote:
>
> > I am wanting to do a lab for students to determine the refractive index
> of
> > various liquids in a semicircular dish (cooking oil, bleach, rubbing
> > alcohol, water, soda, etc.). Does anyone know the index for bleach? I
> have
> > found various tables online for various substance, but I can't seem to
> > find bleach on any of the lists.


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