Re: kinematics, traditional or not

[Bob LaMontagne <rlamont@POSTOFFICE.PROVIDENCE.EDU>]

Robert Cohen wrote:

> *You* know why defining v and a are useful.  *I* know why defining them is
> useful.  Everyone on this list knows why defining them is useful.
>
> My point is that the *students* don't.

I find this puzzling and very much outside my experience with students.
Acceleration is a very concrete entity that students can visualize and have a
feeling that they are "getting Physics" early on in the course. If as much class
time is used to develop the concept of acceleration (e.g. - a ball thrown upward
loses 10 m/s in speed every second) and to spend time doing conceptual type
problems (throw a ball upward at 40 m/s - what is it's speed after 3 seconds)
instead of doing clever but boring calculus derivations of the kinematic
equations, the students will then be receptive to the more abstract and
beautiful ideas contained in Newton's Laws. The calculus is in all the textbooks
- there are better ways for us to use class time.

Even with my engineering students, I have the class do little experiments in the
corridor - such as batting a bowling ball steadily with a rubber bat - so that
they get a visual sense of acceleration. Later, by using bowling balls with
different masses, they can repeat the experiment many times and come to
understand and accept Newton's laws because their own senses agree with the
equations.

Bob at PC