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]

Re: Why work before energy in texts



The work before energy question can only be resolved by performing an
experiment where the order and presence of various elements are varied in
the classroom. At the present time, to my knowledge, this has not been
done, and there is no available evaluation similar to the FCI for assessing
the outcome. However, there are some general principles which do apply to
having students learn the concepts. The most important factor appears to be
using research based material properly. Among the many factors that have
been identified that make the material work are the following:
1. Lecture is extremely ineffective - see the papers by Hestenes, Hake, and
Lawson
2. Connection between the ideas is vital - this result has been the subject
of many papers in JRST and is well known to the education researchers.
Leonard et al. are working on this at U.Mass Amherst.
3. Sequence of material can be important - For example Laws et al have
found that results are improved when impulse-momentum is taught before
energy.
4. Socratic dialog can be used to greatly improve student understanding. -
Hake
5. A series of predict, experiment, resolve cycle is extremely important -
McDermott, Laws et al, Mazur and many others use this method.
6. A learning cycle approach is important - Lawson, Karplus - most research
based materials use a variant of the learning cycle.
7. Realistic problems (rich context) both raise understanding and problem
solving ability - Heller&Heller, and this is also used in Minds on Physics
(MOP) by Leonard et al.
8. Anchor and Bridging analogies can be effective in making connections -
John J. Clement (no relation)
9. Refutational text can also have some effectiveness - Hynd et al. and
others in JRST
10. Time for concepts to be accommodated is vital. - Laws et al (2 weeks
for accommodation), Shayer and Adey "Really Raising Standards"

None of this resolves the question, but the current practice of introducing
work first can be justified under the principle of providing coherent
pedagogy that promotes the acquisition of connected ideas. Once work is
understood, then it can be connected to both kinetic and potential energy.
This also provides an opportunity to perform a number of experiments with
simple equipment that is readily available and is understandable by the
students. When properly presented the ideas can stick together in the
student's head. Achieving this goal may require an extended period of time.
MOP allocates up to a full quarter to achieving this goal.

Unfortunately many (probably most) students do not perceive the value of
proofs, so they do not tend to make connections between the ideas. Formal
proofs are usually taken to merely be a demonstration that it is ok to use
the formula, and are not treated as a connection (see Redish MPEX).
Informal proofs may be more effective, but they can still be ignored.

I suspect that the current conventional sequence probably works well when
used with good research based pedagogy. Conversely, the difference between
various sequences will probably be too small to be measured in conventional
lecture/recitation courses. To test this question you probably need to have
enough gain to be able to see the effect, and in lecture/recitation any
effects will be hidden by the low statistics. As a result an experiment in
a lecture course which changes the order of omits work may show no
difference in learning, but research based material may show a dramatic
difference. Remember that at AzState they found no significant difference
in student learning for any lecturer in either chem. or physics. So bad
lectures may be equally as effective or ineffective as award winning
lectures. You too can be as (in)effective as Feynman.

John M. Clement
Houston, TX