Dear Jim and All,
Pardon my ignorance, but what's a twinky? From here it sort of sounds
vaguely salacious!
On another point, I like your approach to understanding the difference
between energy and power. Would you mind sharing some of the values you use
for energy content?
Cheers,
Pat Naughtin
CAMS - Certified Advanced Metrication Specialist
- United States Metric Association
ASM - Accredited Speaking Member
- National Speakers Association of Australia
Member, International Federation for Professional Speakers
--
on 2002/03/08 04.09, Jim Elwell at [EMAIL PROTECTED] wrote:
> At 11:55 AM 3/7/2002 -0500, James R. Frysinger wrote:
>> I cannot sufficiently express how frustratingly difficult it is to
>> teach students that the concept of power crosses into many areas:
>> electrical, mechanical, thermal, etc. For American students, an obvious
>> source of confusion is the plethora of units that are commonly used, as
>> you have put it above, Duncan. Indeed, they sometimes try to tell me
>> that "these powers are different" on the basis of the differing units. I
>> wonder how my experience compares to that of instructors in physics
>> classrooms in metricated countries.
>
> My experience teaching people, including some who do not even have high
> school diplomas, isn't quite this bad. I use two different methods that
> seem to help.
>
> First, to teach the difference between power and energy, at the start of a
> class I put out two sets of four AA batteries, one running a small penlight
> (wired in parallel), the other running a larger spotlight (wired in
> series). By the end of class the spotlight is dead, while the penlight goes
> for several hours. Everyone inherently understands that the two sets of
> batteries contain the same energy, so it is relatively easy to grasp the
> power being different.
>
> As to the different types of power (and energy), I give them (rounded)
> conversion factors for a variety of units, and have them figure out how
> long a Twinkie will "power" a car, or how long a battery would "feed" a
> human, or how much the natural gas a house uses in a month would if it were
> peanut butter. Using such crazy comparisons helps them grasp that energy is
> energy in whatever form.
>
> Jim Elwell
>
