COMMON UNITS

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

It seems to me that a sure way to lose an introductory class right at the
start (especially a 'liberal arts' class) is to rigorously adhere to
metric/SI units when talking about everyday experiences.  Students (in the
U.S.) have no real feel for meters/second or Newtons, but do understand
miles/hour and pounds.  They can do kinematics calculations in their head
if you use cars moving along the highway at familiar speeds and distances
in their familiar 'miles'.  One of the most memorable segments (for
students) of any film I've used over the years, is the Ring of Truth
(Change) episode where Morrison uses Jelly Donuts as a unit of energy
measure.  Two years later, students still refer to that as the 'Jelly Donut
film.'  

The educational researchers keep telling us that we should work from the
familiar towards the new so I wouldn't be so quick to discard feet, miles,
hours, pounds or even 32 ft/s^2.

Rick

----------
> From: LUDWIK KOWALSKI <kowalskil@alpha.montclair.edu>
>
> The only number I would like to keep secret (responding to Santos) is
> 32 ft/s^2. Conversions to SI? Yes. Doing physics with common units? No.