Re: [Phys-l] Student engagement--GAIN

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

Will have to comment here--as I couldn't disagree more--at least for College 
level courses (so we may be talking past each other).

All I want incoming student to have is a basic understanding of the 
_concepts_ of velocity and acceleration--so do that with whatever works, but 
if you can't think ALGEBRAICALLY and work with the d,v,a,t equations in a 
College Level, problem solving, physics course--you have no business in that 
course--or in any field that requires such a course.

It may be my background as a nuclear physicist and working for years with 
low-energy (below 16 MeV) particle collisions, but momentum is most useful 
as a tool for dealing with collisions, and especially nuclear level 
collisions.  For that I want KE before momentum.  Not interested in coming 
back to collisions later--despise the 52 chapter books now being published!

Rick  ;-)


----- Original Message ----- 
From: "chuck britton" <cvbritton@mac.com>
To: "Forum for Physics Educators" <phys-l@carnot.physics.buffalo.edu>
Sent: Monday, December 07, 2009 3:47 PM
Subject: Re: [Phys-l] Student engagement--GAIN


> A quick note from a retired HS instructor who gained insight from a
> coupla Priscilla Laws Workshops and generally was looking for better
> ways to do things.
>
> d,v,a,t equations are GARBAGE ! ! ! ! ! ! You might work up to them
> eventually - but until the students have a THOROUGH understanding of
> velocity time graphs. (and position time graphs too of course).
> Sonic Ranger exercises are where it starts. Matching, predicting etc.
>
> The velocity graph of straight line segments solves most 'd,v,a,t'
> problems that Rick is concerned about. Finding the area of rectangles
> and triangles  is the analysis they need. The 'smart' ones will even
> use the trapezoid area 'formula', but that's unnecessary gravy.
>
> How many college profs are willing to lower their teaching  style to
> using geometry instead of the usual dvat formulas?
>
>
> (Oh, and teaching momentum before KE works really well too -
> but that's for another day)
>
> Rick writes:
>
> > The only GAIN I'm interested in from pre-College courses, is that I start
> > seeing some students who know some basics (say understand velocity and
> > acceleration)--so that we don't have to start from scratch.
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