Re: Physics First (lengthy reply)

[Dave Hamilton <djhamil@teleport.com>]

> I would fully support the original proposal, but ordered Physics,
> Chemistry, and Biology WITH the fourth year advanced course. 
> Obviously this requires a committment from the school system for FOUR
> years of HS science!  The current order of Bio, Chem, Physics was
> chosen many decades ago because of  ALPHABETICAL ORDERING :-(   The
> new ordering makes sense from the point of view that Chemistry is
> applied Physics and Biology is applied Chemistry ;-)   Of course, such
> an ordering all but demands that the initial Physics course be of a
> 'conceptual' nature without lots of algebraic problem solving (but not
> necessarily devoid of such).  From the point of view of a College
> Professor whose (non-physics-major) students have almost all had HS
> physics but less than 1/4 of these seem to know any physics, I'd
> prefer that everyone have at least one strong conceptual course before
> attempting the more traditional 'problem-solving' course.  I think the
> Physics Educational Research community ( Dewey et. al.) might concur. 
> The fourth year option then permits those really interested in
> Physics to take an AP level course (or equivalent).
>
> Rick

Whenever this debate arises, there appear two camps:  those that argue 
for an order based on the structure of the knowledge (as Rick does above) 
and those that argue based on pedagogical concerns (Rick refers to a 
pedagogical concern when he addresses the lack of math ability in the 9th 
graders).  The "structure of the knowledge" argument is powerfully 
attractive, especially to physics types, because, like physics, it is a 
reductionistic, task-analysis approach.  In other words, the argument 
breaks the 'whole' down into 'pieces' and looks to order those pieces 
with an argument such as "students must know A before they can learn B, 
etc." This mirrors the physical science model of breaking a problem down 
into its parts or 'pieces', solving the pieces, and constructing a 
logical argument (by ordering the solutions to the pieces).  This is 
highly successful for the types of problems that fit in the physical 
science domain (such as explaining the photoelectric effect).

Problems such as "how do students learn science?" do not fit well in the 
physical science paradigm.  I suggest that a reductionistic, 
task-analysis approach is not suitable for address such a question.  
Instead, we need to look at how students learn science.  Using 
constructivism as a theoretical basis, we know that students' learning of 
science is most effective when they can connect the subject matter under 
study with concepts and structures that are already in place.  If I tell 
a student an answer to a question that she has never asked, or even 
worse, if I tell a student an answer to a question she doesn't even 
understand, I can expect that the student won't learn the answer (she 
may, however, recall it for a test at the end of the unit). If, on the 
other hand, I can order my instruction so that I assure that the 
knowledge I would like the students to construct is directly connected to 
things that the student is already thinking about, meaningful learning 
can occur (the student will know the answer, not just at the end of the 
unit, but for life).

Concerning the question of "which order is better: biol., chem. phys. or 
phys., chem., biol.?":   I think that 9th graders are (a) more interested 
in living things than physical entities, and (b) find the questions and 
problems of biology more accessible and meaningful than the questions of 
chemistry and physics.  I leave point (a) as a given (it may be argued, 
but I'm already running long on this post).  As for point (b), in 
chemistry and physics, the questions and problems are about abstract 
entities such as elements, atoms, forces, and energy.  A typical physics 
question (conceptually-based, from a well-known study of how well physics 
students understand their physics) is the one where you ask about the 
forces acting on a coin that has been tossed in the air:  what are the 
forces acting on it when it is on the way up? at the top? on the way 
down?  My research indicates that 9th graders don't normally concern 
themselves with the question of what goes on at various points along a 
complex trajectory.  I believe the reason students performed so poorly on 
this type of iem is that, even though they were taught about the forces 
acting throughout a projectiles' motion, the information was not 
connected to what the student already knew and was intersted in.  In 
biology class, however, the students begin studying questions that are 
more accessible such as "in what ways are plants and animals alike?  
different?,  what makes me look like my parents?"  Sure, they don't get 
very far in answering these questions before they run up against the need 
to know some chemistry and physics.  But this is exactly what I believe 
makes this ordering better than the reverse - when the students encounter 
a need to know chemistry, they will be ready to learn chemistry. 

Finally, like Lowell Herr and others, I do not accept the assumption that 
the learning of science is best approached by having courses in biology, 
chemistry, and physics (no earth science?).  Teaching science as a 
collection of separate disciplines fits well with the reductionistic, 
"structure of knowledge" approach to pedagogy.  I'm not convinced it fits 
so well with how students learn science.  If you are familiar with the 
National Science Teachers Association (NSTA) and their Scope, Sequence, 
and Coordination (SS&C) project, you have heard the arguments for moving 
away from the "layer-cake approach" (biol., chem., phys.) toward an 
integrated approach.  If you are sincerely interested in the question of 
which order is better, and particularly if you plan to implement such a 
change in your school, you would be wise to be aware of what the leaders 
in secondary science are saying about this matter.  You may not agree 
with SS&C, but you should consider the possibility of science classes 
which are not segregated by discipline.  If you're concerned about the 
practicality of completely switching over to an integrated approach, you 
might consider a compromise solution of a ninth-grade integrated approach 
which introduces the big ideas in all the disciplines, followed by the 
traditional layer-cake approach.  Personally, I believe there comes a 
time to immerse oneself in a discipline such as physics and struggle to 
enter the physics paradigm.  I just don't think 9th grade is the time to 
do it for most of our students.

Sincerely, and long-windedly,
Dave



David J. Hamilton, Ed.D.                    "And gladly wolde he lerne,
Franklin HS, Portland, OR                    and gladly teche."
djhamil@teleport.com                          Geoffrey Chaucer