Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

[Phys-L] Re: Energy is primary and fundamental? (was RE: First Day Activities or Demos)



I'll let others who have done it speak to how to do it. I'd like to
make a different comment.

The assumption in your question Dan is that force is a well defined
concept, when indeed it is not. We are familiar with something we call
force, pushes and pulls, but if you look more generally at something,
how do you know it is experiencing a force. It was enough of an
embarrassment to Newton, in particular about gravity, that he made no
claims about it, only that if you assumed its presence things seemed to
work nicely.
In the late 19th century several folks worked out ways to do mechanics
without force.

I am only suggesting that you need to be careful to give force some
sort of unexamined primacy. Given that, you could start with
energy...you just have to work out the pedagogy, which I think has been
done.

cheers,

joe
On Aug 10, 2005, at 12:09 PM, Dan Crowe wrote:

John,

Some physicists advocate starting a first course in physics at the high
school level with energy and energy conservation, but I don't know how
to do that.

How do you define energy without reference to force or work?

How can high school students develop an understanding of energy and
energy conservation at the beginning of their first course in physics?

What guidance should a teacher provide in this process?

Daniel Crowe
Oklahoma School of Science and Mathematics
Ardmore Regional Center
dcrowe@sotc.org

-----Original Message-----
From: Forum for Physics Educators [mailto:PHYS-L@list1.ucc.nau.edu] On
Behalf Of John Denker
Sent: Wednesday, August 10, 2005 9:58 AM
To: PHYS-L@LISTS.NAU.EDU
Subject: Re: [PHYS-L] First Day Activities or Demos

<snip>

The process may be student-oriented and student-centric, but it
is still teacher-led.

I've read some of the standard references on "inquiry" and they
give me the heebie-jeebies, because they grossly understate the
amount of guidance that the teacher must provide in order to
make "inquiry" work. Sometimes the guiding hand is obvious;
sometimes it is more subtle ... but you cannot do without it,
especially early in the year.

<snip>

-- Energy is primary and fundamental. You don't need to know
anything about work or force or acceleration or vectors to
know what energy is, and to know that it is conserved.


Joseph J. Bellina, Jr. Ph.D.
Professor of Physics
Saint Mary's College
Notre Dame, IN 46556