II. EVIDENCE OF A MISMATCH BETWEEN
STANDARD CURRICULUM AND TEACHERS
The only university instruction that most teachers receive
on topics in K-12 physics and physical science occurs in
physics departments. However, there is ample evidence from
research that a large gap often exists between what is taught
and what is learned in physics courses at all levels of
instruction.
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The situation is of special concern in the stan-
dard courses taken by future high school teachers as well as
in the descriptive courses that may be taken by prospective
elementary and middle school teachers.
The three examples that follow are from investigations by
our group. In each, the context is a qualitative question on a
topic common to precollege and university curricula.
A. Mismatch for K-5 teachers: Example in the context
of balancing
Elementary school curricula often include a unit on
balancing.
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A question based on the diagram in Fig. 1 was
used to probe understanding of this concept in two different
populations.
4
Students were told that a baseball bat of uni-
form mass density is balanced on a finger and were asked to
compare the total mass to the left and right of the balance
point. This question was administered to about 675 students
in introductory calculus-based physics and about 50 inser-
vice K-5 teachers. The introductory students had completed
their study of the relevant topics. Many of the elementary
school teachers had previously taught units on balancing.
Only about 20% of the introductory physics students and
about 15% of the K-5 teachers responded correctly. Nearly
everyone who gave an incorrect answer claimed there must
be equal mass on both sides.
Along with a description of suggested activities, the teach-
er’s guide accompanying one of the units includes the fol-
lowing statement: “Every object
共or system of connected ob-
jects
兲 has a point around which the mass of the system is
evenly distributed. This point is the center of gravity.”
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There seems to be a tacit assumption that the teacher already
understands the material or can quickly learn by reading.
However, the results from the question on the baseball bat
suggest that the term “evenly distributed” may inadvertently
reinforce an incorrect belief that is common among teachers
and students.
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