Re: [Phys-l] "unlearning"

["Dr. Richard Tarara" <rtarara@saintmarys.edu>]

We do even more and approach the pendulum without talking about it at all in 
'lecture'.  Here is what a pendulum looks like--you can time the swing--what 
does that time depend on?  Breaking the class into groups to examine 
different possible variables (which the class has identified), they study 
period versus mass of the bob, period versus angle of swing, and period 
versus length (broken into three length regions (0-1m, 1-3m, 3-10m).  The 
last two ranges give data that 'could' be interpreted as linear which leads 
to learning about consideration of as large a variable range as possible 
since all three ranges combined are clearly not linear.  The angle of swing 
study shows a reasonably constant period out to 30 degrees with definite 
deviation towards longer periods beyond.

Later in class we look first at the small angle approximation and then the 
problem with large angles--both, as is traditional, by approximating the 
pendulum as a SHM oscillator.

If you will, this is a 'discovery' mode exercise that works pretty well. 
Pretty difficult to design the entire curriculum this way, especially if you 
have constraints to cover a lot of topics, but the pendulum fits very nicely 
into the mode.

************************
As usual on the list, everyone has some strong feelings about what should be 
taught and how it should be taught.  What is correct or effective pedagogy. 
Also as usual, lots of those feelings and suggestions (demands) may not be 
applicable to the particular audience and/or goals of other people's 
courses.  Trust yourself.
*************************

Rick

***************************
Richard W. Tarara
Professor of Physics
Saint Mary's College
Notre Dame, IN
rtarara@saintmarys.edu
******************************
Free Physics Software
New multi-input energy simulator--plays similar to the Montana State analog 
computer.
www.saintmarys.edu/~rtarara/software.html
*******************************


----- Original Message ----- 
From: "Spagna Jr., George" <gspagna@rmc.edu>
To: "Forum for Physics Educators" <phys-l@carnot.physics.buffalo.edu>
Sent: Friday, September 10, 2010 12:29 PM
Subject: Re: [Phys-l] "unlearning"


> In particular reference to the period of a pendulum.  We routinely cover 
> this in a lab exercise, in which we tell the students of Galileo's 
> "discovery" that the period is independent of amplitude, and ask them to 
> confirm or refute it.  This exercise also requires them to assign 
> uncertainties to their measurements and begin to trust the data even when 
> it contradicts the "authority" of some famous scientist of old.
>
> *******************************************************
>             "... politics determines who has the power,
>                                not who has the truth."
>                                       - Paul Krugman
> *******************************************************
>
> Dr. George Spagna
> Physics Department
> Randolph-Macon College
> P.O. Box 5005
> Ashland, VA 23005-5505
>
> phone: (804) 752-7344
> fax: (804) 752-4724
> e-mail: gspagna@rmc.edu<mailto:gspagna@rmc.edu>
> http://faculty.rmc.edu/gspagna/public_html/index.html
>
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