Re: [Phys-l] A physics resource for teachers and studens

["John Clement" <clement@hal-pc.org>]

It seems to be a condensed conventional text in hypertext form with
conventional demos where the answer is implied as part of the text.  As such
it should work no better of worse than conventional physics instruction.

Some of the movies could be used profitably, but they need to be surrounded
by interactive lecture demo techniques, and the demos need to be carefully
sequenced to help students dispel misconceptions.

It seems to be missing most of the insights from PER.  For example they do
not use bar charts in the section on conservation of enrgy, but bar charts
have been shown to be very important to helping students make sense of
conservation.  The section on NTN3 does not bring out the importance of the
idea of interactions, and never states that not only are the pair of forces
opposite, and equal, but that they are on different objects and of the same
kind. Many students do not realize that identifying NTN 3rd law pairs
requires all of these conditions.  Also the contrast between NTN 3rd law
pairs and "balancing" forces on one object needs to be brought out.  In the
truck/car example while they do use refutational text, the student is not
given time between the "question" and the "answer" to reflect on what they
think.  This particular sequence of predict, confront, resolve has been
shown to be quite important in helping students confront their
misconceptions.

They also do not use consistent notation for kinetic energy, as they use the
traditional KE rather than E_k, so the unity of energy is deemphasized.
They use F_g = m g where g=9.81 m/s^2 rather than the more comprehensible
units N/kg.  It makes no sense to students to use NTN2 in this context
because NTN2 has acceleration, and a stationary object has no acceleration,
but there is a gravitational force.  g really comes from the NTN
gravitational law and not NTN2.  The conventional approach confuses the heck
out of students.

I would say this could be used as a reference AFTER good pedagogy has been
used in a coherently structured class.

John M. Clement
Houston, TX

> Someone just sent me this URL:
>
> http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html
>
> Any comments about these materials?
>
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