Preparing K-12 teachers to teach physics and physical science
Lillian
C. McDermott, Paula R.L. Heron and Peter S. Shaffer
The
task of preparing K-12 teachers to teach science is an important (though often
unacknowledged) responsibility of science faculty. In
recent years, a steadily increasing number of physics departments have begun to recognize
the need to take a more active role in the professional development of K-12 teachers of
physics and physical science. The APS and
AAPT, together with the AIP, have endorsed this trend with supportive statements and with
a proposal to NSF that led to the creation of PhysTEC. However, if these developments are to lead to a long-lasting positive
impact, it is necessary to recognize the inadequacy of the preparation usually offered in
physics departments and to reflect on the characteristics of instruction that has been
shown to be more effective.
I. Inadequacy
of current preparation in physics departments
Most
physics departments do little for prospective elementary and middle school teachers. The only courses generally available are almost
entirely descriptive. A great deal of
material is presented, for which these students have neither the background nor the time
to absorb. The net effect is to reinforce a
tendency to perceive physics as an inert body of information to be memorized, not as an
active process of inquiry. The addition of
"hands-on" activities is not enough to prepare elementary school teachers to
teach basic physical science in a way that is meaningful to their students.
Most
high school physics courses are taught by teachers who have not majored in the subject. Often they are not much better prepared than
university students who have taken a standard introductory course. Although this course covers the content of high
school physics, it is not adequate preparation for teaching the same material. The breadth of topics allows little time for
acquiring a sound grasp of the underlying concepts. The
routine problem solving that characterizes most introductory courses does not develop the
reasoning ability necessary for handling the unanticipated questions that may arise in a
classroom. The accompanying laboratory
courses generally do not address the needs of teachers. Often the equipment is not available in high schools and no provision is
made for laboratory experiences that utilize simple apparatus. A more serious shortcoming is that experiments are
mostly limited to verification of known principles. Students
have little opportunity to start from their observations and go through the reasoning
involved in formulating these principles. It
is possible to complete a laboratory course without confronting critical conceptual issues
or having experience with the scientific process.
The
relatively few students who decide early that they want to teach physics in high school
may major in physics (perhaps with fewer course requirements). However, the abstract formalism that characterizes
upper division courses is not of immediate use in the precollege classroom. Courses on "cutting-edge" topics may be
motivational but do not help teachers distinguish between memorization and substantive
understanding.
It is
tempting to believe that enriching the standard introductory physics course with
innovative, research-based materials will adequately prepare future high school teachers. Such "reformed" courses may be more
engaging than standard courses but they fail to address many of the intellectual issues
that confront high school teachers of physics. Moreover,
most physics courses have a major shortcoming. Many
teachers cannot, on their own, separate the physics they have learned from the way in
which it was presented. If taught by lecture, they are likely to lecture, even if it is
inappropriate for their students.
II. Need for special physics
courses for teachers
Neither
a modified descriptive course for elementary teachers nor a reformed introductory course
for high school teachers offers the right type of preparation. There is a need for special physics courses for
teachers from the elementary through high school grades. These courses should be laboratory based and have intellectual objectives
and an instructional approach that are mutually reinforcing. The topics should be relevant to the K-12
curriculum and taught in a manner that is consistent with how teachers are expected to
teach. This perspective on teacher
preparation results from a distillation of what the Physics Education Group at the
University of Washington has learned from more than 30 years of experience in preparing
preservice (future) and inservice (practicing) teachers to teach physics and physical
science at the elementary, middle, and high school grades.[i]
A.
Intellectual objectives
Teachers
should be given the time and guidance necessary to develop concepts in depth and to
construct a coherent conceptual framework. They
need to be able to formulate and apply operational definitions so that they can recognize
precisely and unambiguously how concepts differ from one another and how they are related. Such conceptual clarity is not the outcome of a
typical introductory course but is vitally important for teachers.
There
is ample evidence by now from research that success on numerical problems is not a
reliable indicator of functional understanding, (i.e.,
the ability to do the reasoning underlying the development and application of concepts).[ii] Although high school teachers should be able to
solve the types of problems found in typical introductory texts, the emphasis in courses
for K-12 teachers should not be on mathematical manipulation. The development of quantitative reasoning ability,
which should be a goal at all grade levels, does not automatically occur before or after
enrollment in college. For example, it has
been shown that students in university physics courses often cannot reason with ratios and
proportions.[iii] The ability to do proportional reasoning and
interpret the meaning of a ratio in terms of physical quantities (e.g., g/cm3) is a critically important
skill for all who teach science from elementary through high school. Teachers should also be able to use and interpret
formal representations (such as graphs, diagrams, and equations) that are appropriate to
the grades that they teach. They should be
able to relate representations to one another, to physical concepts, and to real world
phenomena.
An
understanding of the nature of science should be an important objective for all teachers. They must be able to distinguish observations from
inferences and to do the reasoning necessary to proceed from observations and assumptions
to logically valid conclusions. They need to
recognize what is considered evidence in science and what is meant by an explanation. They should understand what is meant by a
scientific model - how it is constructed and used and what its limitations are. Teachers need to be given the opportunity to
examine the nature of the subject matter, to understand not only what we know, but on what
evidence and through what lines of reasoning we have come to this knowledge. The scientific process is most effectively taught
through direct experience.
The
objectives above are appropriate for all students but expectations for teachers should be
greater. They need to have a deeper
conceptual understanding than their students are expected to achieve. They must be able to set learning objectives that
are intellectually meaningful and developmentally appropriate for their students. They need to be able to recognize and learn how to
help students overcome difficulties that research has shown to be common. They must develop the judgment necessary to
evaluate instructional materials (e.g., science
kits, textbooks, laboratory equipment, and computer-based tools). This type of pedagogical content knowledge is not
developed in standard physics courses, nor in science methods courses offered by
departments of education.
B.
Instructional approach
If the
ability to teach by inquiry is a goal of instruction, teachers need to work through a
substantial amount of content in a way that reflects this spirit. A useful instructional
approach for this purpose can be summarized as guided inquiry. Teaching is not by telling but by asking carefully
structured questions to help students do the reasoning required to develop a functional
understanding.
Science
instruction for young students is known to be more effective when concrete experience
establishes the basis for the construction of scientific concepts.[iv] We and others have found that the same is true for
adults, especially when they encounter a new topic or a different treatment of a familiar
topic. Therefore, instruction for prospective
and practicing teachers should be laboratory-based. However,
"hands-on" is not enough. Unstructured
activities do not help students construct a coherent conceptual framework. Carefully sequenced questions are needed to help
them think critically about what they observe and what they can infer. When students work together in small groups,
guided by well-organized instructional materials, they can also learn from one another.
The
instructional materials in a course for teachers should be consistent with those used in
K-12 science programs, but the curriculum should not be identical. As mentioned earlier, a course for teachers should
develop an awareness of common student difficulties. Some are at such a fundamental level that, unless they are effectively
addressed, meaningful learning of related content is not possible. Serious difficulties cannot be overcome through
listening to lectures, reading textbooks, participating in class discussions, or
consulting references. Like all students,
teachers need to work through the material and have the opportunity to make their own
mistakes. When difficulties are described in
words, teachers may perceive them as trivial. Yet
we know that often these same teachers, when confronted with unanticipated situations,
will make the same errors as students. As the
opportunity arises during the course, the instructor should illustrate instructional
strategies that have proved effective in addressing specific difficulties. Without specific illustrations, it is difficult
for teachers to envision how to translate a general pedagogical approach into a specific
strategy that they can use in the classroom.
Because
it is critical that teachers be able to communicate clearly, group discussions and writing
assignments should play an important role in a physics course for teachers. Providing multiple opportunities for teachers to
reflect upon and to describe their own conceptual development can enhance both their
knowledge of physics and their ability to formulate the kinds of questions that can help
their students deepen their understanding.
III. Implementation
of special physics courses for teachers
There
are a number of challenges that must be met in implementing a teacher preparation program
in a physics department, especially at a large, research-oriented university. The argument may have to be made to the department
and higher administrative units that the proposed courses are at an intellectual level
worthy of the credit offered. It is necessary
to show that the demands on the students match, or exceed, those of other physics courses
at comparable levels. There are also other
complications. Laboratory-based instruction
is necessary and classes must be small enough to foster interaction among the
students and between the students and instructor. Such
classes are more expensive than large lectures but are a worthwhile investment for
teachers whose potential influence is much greater that that of other students. Another problem may be low class enrollment. In particular, it is often difficult to identify
future elementary school teachers. They are
unlikely to decide, on their own, to take physics. This
problem may be alleviated by encouraging the participation of non-science majors, for whom
the course could satisfy a science requirement.
It is
also unlikely that it will be possible to fill a class for prospective high school
teachers with physics majors who plan to teach. Most
high school physics teachers were not physics majors and, at best, may have majored in
chemistry or mathematics. The situation among
prospective teachers is similar. It is both
practical and highly desirable that participation in the course by students majoring in
other sciences and in mathematics be strongly encouraged. The course can be open to all students who have taken the standard
introductory physics course. For science
majors who may not be ready to make a commitment to high school teaching, it may be useful
to add the course to the list of electives in their major. The range of preparation can vary broadly because the emphasis is not on
quantitative problem solving but on concept development and reasoning. The presence of non-majors may help make the
entire class more willing to forego a reliance on formulas and to think more deeply about
the physics involved.
IV. Conclusion
The
separation of instruction in science (which takes place in science courses) from
instruction in methodology (which takes place in education courses) decreases the value of
both for teachers. Even detailed directions
cannot prevent misuse of excellent instructional materials when teachers do not understand
either the content or intended method of presentation. Since the type of preparation that teachers need
is not available through the standard physics curriculum, a practical alternative is to
offer special courses for teachers. The
instructors in such courses must have a sound understanding of the subject matter, of the
difficulties that it presents to students, and of effective instructional strategies for
addressing these difficulties. Unless
faculty are prepared to devote a great deal of effort over an extended period to develop
their own inquiry-oriented curriculum, they should take advantage of already existing
instructional materials that have been carefully designed and thoroughly tested with
teachers. Special courses may require
additional resources but it is vitally important (and in their long-term interest) that
physics departments make this investment in K-12 education.
Acknowledgments
The
views expressed above are based on the work of many past and present members of the
Physics Education Group, including K-12 teachers. Our
comprehensive program in research, curriculum development and instruction has been
supported by the University of Washington Physics Department and the National Science
Foundation.
References:
[i] This
paper builds on others by the Physics Education Group.
In particular, see L.C. McDermott, "A perspective on teacher preparation in
physics and other sciences: The need for special courses for teachers," Am. J. Phys. 58, 734-742 (1990).
[ii] See
L.C. McDermott and E.F. Redish, "Resource Letter PER-1: Physics Education Research," Am. J. Phys. 67, 755-767 (1999). Although
most of the studies cited refer to students at the university level, similar difficulties
have been identified among younger students.
[iii] See A.B. Arons, A Guide to Introductory Physics Teaching (Wiley,
New York, 1990), pp. 3-6.
[iv] See for example, J. Griffith and P. Morrison,
"Reflections on a decade of grade-school science," Phys. Today
25 (6), 29-34 (1972); R. Karplus,
"Physics for beginners," Phys. Today 25 (6), 36-47 (1972); and J.W. Renner, D.G.
Stafford, W.J. Coffia, D.H. Kellogg, and M.C. Weber, "An evaluation of the Science
Curriculum Improvement Study," School Science
and Mathematics 73, 291-318 (1973).
Lillian C. McDermott, Peter S.
Shaffer, and Paula R.L. Heron are faculty members in the Physics Education Group in the
Physics Department at the University of Washington. The
group consists of physics graduate students, postdocs, faculty and K-12 teachers who
conduct a coordinated program of research, curriculum development, and instruction to
improve student learning in physics (K-20). The
group is engaged in ongoing research on the learning and teaching of physics that has
resulted in more than 50 research articles. For
more than 30 years, they have been deeply involved in the preparation of prospective and
practicing teachers to teach physics and physical science by inquiry. The group has also published research-based
tutorials to improve the effectiveness of instruction in introductory university physics. |