Re: Is it necessary or helpful to teach work (W) in introductory HS physics? (long)

[chuck britton <Britton@NCSSM.EDU>]

My philosophy would be to include work as the segue from Forces into
Conservation of Energy. In fact, I have come to define work as the
PROCESS of changing energy from one form into another form.

Simple machines are VERY concrete examples. Include 'thermal energy'
(sometimes called heat - shudder) when friction is a consideration.


At 1:02 PM -0600 6/27/02, Daniel Price wrote:
> I did not find a discussion of the above-referenced topic in a cursor=
> y=20
> search of the archive.  I hope that those of you who have argued the=
> =20
> subject exhaustively will forgive me for reintroducing it.
>
> In teaching first-year, non-AP physics at the high-school level, I ha=
> ve=20
> noticed that work seems to be the difficult topic for students to=
> =20
> understand.  The curriculum as I have implemented it covers
> W =3D F =95 d and W =3D delta-K, and were students able to grasp the =
> abstract=20
> nature of work, we would presumably have made an elegant transition b=
> etween=20
> study of force and examination of energy.
>
> The difficulty that we all seem to face is in covering essential mate=
> rial=20
> to the necessary level of depth in the allotted time.  Experience has=
> =20
> taught me that regardless of how quickly I wish to cover certain topi=
> cs,=20
> the class will move at its own pace.  Ultimately, I am left with too =
> little=20
> time to give fundamental topics (such as conservation of mechanical e=
> nergy)=20
> their due.
>
> The question (finally), then, is:  how important is the topic of work=
>  to a=20
> solid understanding of basic physics?  Can I sacrifice W, allowing mo=
> re=20
> time for energy conservation (and for whatever else needs shoring up)=
> ?
>
> Because this question is rather open-ended, I am happy to list the=
> =20
> possibilities that I am exploring, should they provide a helpful=20
> "jumping-off point".  Feel free to ignore them.
>
> =09=95  Continuing as we have over the last few years:  W =3D F =95 d=
>  =3D delta-K =3D=20
> -delta U
> =09   [I am oversimplifying for purposes of brevity.]
>
> =09=95  Eschewing the topic of work altogether, and discussing conser=
> vation of=20
> mechanical
> =09   energy in greater depth.
>
> =09=95  Discussing work in the context of mechanical advantage and si=
> mple machines
> =09   (i.e. using a more concrete definition, rather than the abstrac=
> t=20
> notion, of W)
>
> I do have a preference, but am most willing to hear the opinions of o=
> thers=20
> who have experienced similar quandaries.  Thanks in advance.
>
> [For reference, our school (public, middle-class suburban) has four p=
> hysics=20
> offerings (total physics enrollment--150):  conceptual physics, physi=
> cs,=20
> honors physics, and AP Physics C.
> The honors-level course is used to prepare students for college or AP=
> =20
> physics courses.  The most popular of the four offerings is "plain-ol=
> '=20
> physics", taught as an introduction with some eye toward college-prep=
> =20
> although most of those enrolled do not plan careers in physical scien=
> ce or=20
> engineering.  The question "do work or don't do work" is meant to add=
> ress=20
> the needs of students in physics; those in honors and AP should and c=
> an=20
> handle the abstract approach to the topic of work.]