An Introduction to Physics Education Research
This document is a brief introduction to Physics Education Research (PER)
and how the results of this research is used in teaching.
Overview
Physics teachers have long suspected that our beginning students hold many
basic concepts about the physical world that are in conflict with the "scientific"
worldview that largely originated with Kepler, Galileo, and especially Newton.
In the early 1990's work began on developing diagnostic instruments to probe
just how prevalent these mis-conceptions are and exactly what they are. A well-known
example is the following question.
A semi-circular track is fixed to a tabletop. In the figure, we are looking
down on the track from above. A small ball is rolled at high speed into
the track at point p. The ball rolls around through points q and r,
and emerges from the track. Which of the paths A, B, C is
closest to the path that the ball will follow?
Often a plurality or even majority of beginning physics students choose A.
This fundamental mis-conception is deeply held by many students. When
doing an actual demonstration, some students claim they actually saw the
ball follow path A! I have placed a meter stick beside
path B and repeated the demonstration and had students
say "There must be magnets or something in the meter stick that
caused the ball to follow path B, because before it
followed path A." |
 |
The diagnostic instruments revealed many similar mis-conceptions. So they
confirmed our suspicions.
The next step was to give the same diagnostic instrument to students at the
beginning and again at the end of their physics course. The expectation was
that we could then observe our grand success in having students replace wrong
concepts with correct ones. However, the results of this pre/post test protocol
was underwhelming: the change in student understanding was minimal. So evidently
conventional instruction is not very effective. Students learn to memorise
formulae and on tests "plug and chug" to get correct answers, but the deep
conceptual learning which we particularly value was not occurring in our classes.
This depressing result has now been replicated for tens of thousands of students
at a number of institutions around the world.
If conventional instruction is not effective, the diagnostic instruments
allow us to conduct research to try to find pedagogy that actually works. After
forming a baseline with the pre/post test protocol in a course, the following
year make a change in the instruction and use the instruments to determine
whether the change actually worked. This method of applying the scientific
method to pedagogy is the heart of PER.
Some of the key results of PER are:
- Most students learn best by interacting with their peers. This result was
particularly shocking to me. My preferred learning style is give me the
textbook or journal article and a quiet corner and leave me alone! I
suspect this is also the preferred learning style of many people who end
up academics. However, it is not the best learning style for most of our
students.
- The peer interactions are most effective when they are based on conceptually
based activities. These activities are particularly effective when they force
students to confront their mis-conceptions.
- The activities are particularly effective when they involve real physical
apparatus. The apparatus need not be sophisticated or expensive: often materials
available at minimal cost from the local hardware store can be effective.
Many skilled educators in a variety of fields have at least intuitively known
these results. The difference is that PER allows us to quantitatively prove
that these methods actually work.
PER is now a huge field of research. PER groups now exist in many physics
departments, Physical Review has a Special
Topics Section on PER,
and googling "physics education research" returns 63,000 hits.
Applying PER
In this section I briefly describe how the results of PER are being applied
in teaching physics.
Classes
Often we have up to 1000 students in a classroom. In conventional instruction
we deliver a lecture to the students. We stand at the front of the room and
deliver the "truth" which the students are expected to passively absorb.
The origins of the lecture is the middle ages, where the professor would come
in to the classroom and read the book to the students. A few days later, the
professor would again read the book to the students, perhaps adding some commentary.
A few days after that he would again read the book to the students; this is
the origin of the "third reading" which is still used in our parliaments. This
type of pedagogy is perhaps appropriate if the professor is the only one with
the book. However, the invention of the printing press in 1440 means that students
also have the book. Thus the persistence of the conventional lecture can only
be viewed as an anachronism based on habit, tradition, and perhaps just laziness.
Given that students learn best by interacting with their peers, how can this
fact be implemented in a classroom with many students? One technique is called Peer
Instruction (PI), whose greatest proponent is Eric Mazur at Harvard. Here
is how Crouch and Mazur describe the method:
A class taught with PI is divided into a series of short
presentations, each focused on a central point and followed
by a related conceptual question, called a ConcepTest which probes students’ understanding
of the ideas just presented. Students are given one or two minutes to formulate
individual answers and report their answers to the instructor.
Students then discuss their answers with others sitting
around them; the instructor urges students to try to
convince each other of the correctness of their own answer
by explaining the underlying reasoning. During the discussion,
which typically lasts two to four minutes, the instructor
moves around the room listening. Finally, the instructor calls
an end to the discussion, polls students for their answers
again ( which may have changed based on the discussion),
explains the answer, and moves on to the next topic.
("Peer Instruction: Ten
years of experience and results," Am. J. Phys. 69(9),
970 - 975, (Sept. 2001),
http://web.mit.edu/jbelcher/www/TEALref/Crouch_Mazur.pdf)
Demonstrations
Physics classes often have demonstrations, and students love them. However,
research shows that they don't actually learn very much from conventional demonstrations. Interactive
Lecture Demonstrations (ILD) are an educationally effective modification
of conventional demonstrations. In this method students make predictions of
the outcome of a demonstration and collaborate with fellow students by discussing
their predictions in small groups. Students then examine the results of the
live demonstration.
Tutorials
At some institutions tutorials are known as recitation sections.
A small group of students meets with a graduate student teaching assistant
or in some cases the professor. In conventional instruction, these meetings
allow for student questions and problem solving. Often they degenerate into
mini-lectures by the TA or professor.
In modern PER-based instruction, most of the session is devoted to having
students working in teams of 3 - 5 students on conceptually-based activities.
The typical model is guided-discovery, in which the TA or professor
uses a Socratic method where student questions are typically answered by another
question. Devoting a small fraction of time to the conventional tutorial content
is common.
In addition to the McDermott tutorial materials listed below in the Resources section, many textbooks now include Student Workbooks which provide activities
for these PER-based tutorials.
Laboratories
We can characterise the goals of typical laboratory instruction as:
- Providing experimental illustration of the concepts of the course.
- Illustrating methods of experimental science, often including error analysis.
Typically a mixture of these two goals occurs in some proportion.
Goal 1 has considerable overlap with the PER-based tutorials.
Resources
Here I provide listings and links to resources to learn more about PER and
how it is being applied. It is not exhaustive, but rather some personal favorites.
Introductions
Randall D. Knight, Five Easy Lessons:Strategies for Successful Physics
Teaching (Pearson Addison Wesley, 2002), ISBN-10: 0805387021. ISBN-13: 978-0805387025.
Randy Knight is the author of the very successful textbook Physics
for Scientists and Engineers (Pearson Addison Wesley). Here he
discusses the theoretical basis for the way this text is constructed. I
am not aware of a version available on the web, but your Pearson rep can
supply a copy.
Edward F. Redish, Teaching Physics with the Physics Suite (Wiley,
2003), ISBN-10: 0471393789, ISBN-13: 978-0471393788
http://www2.physics.umd.edu/~redish/Book/
Although the title of this book indicates that it is an instructor's guide
for a package of materials published by Wiley, it is also a lovely introduction
to PER and its application in a variety of educational contexts.
Jonathan Hillel, "Physics Education Research – A Comprehensive
Study" (2005)
http://www.upscale.utoronto.ca/PVB/JonathanHillel/FullReport.pdf
This is a B.Sc thesis written at the University of Toronto. In addition
to an overview of PER, it includes some experiments in applying PER.
Classes
The Mazur Group, "Peer Instruction",
http://mazur-www.harvard.edu/research/detailspage.php?ed=1&rowid=8
This web page provides an overview of Peer Instruction and many links to
further discussions.
Douglas Duncan, Clickers in the Classroom (Pearson Addison
Wesley, 2005), ISBN : 0-8053-8729-5. The forward and first two chapters are
available at:
http://www4.uwm.edu/ltc/srs/faculty/docs/ClickersInTheClassroom.pdf
Although clickers (aka Classroom Response Systems) can be used in a variety
of educational settings, they have been used extensively with both Peer Instruction
and "Just In Time Teaching". This small booklet provides an overview of clickers
and their possible uses.
Harlow et al., "What’s all the clicking about? A study of Classroom
Response System use at the University of Toronto" (2008)
http://faraday.physics.utoronto.ca/PVB/Harrison/Clickers/Clickers_PVB.pdf
This is a report on a survey of the use of clickers at the University of
Toronto. Over 30 U of T instructors were
interviewed about their use of clickers in classes with a total enrolment
of over 5,000
students.
Demonstrations
David l. Sokoloff and Ronald K. Thornton, "
Using interactive lecture demonstrations to create an active learning environment", Phys.
Teach. 35(6), 340 - 347, (Sept. 1997).
http://scitation.aip.org/dbt/dbt.jsp?KEY=PHTEAH&Volume=35&Issue=6
This is the paper that brought Interactive Lecture Demonstrations to the
attention of many physics instructors.
Tutorial and Laboratories
Lillian C. McDermott, Peter S. Shaffer, Tutorials in Introductory
Physics (Prentice Hall, 2002),
ISBN 0-13-065364-0.
Lillian McDermott and her group at the University of Washington have raised
the use of conceptual activities to put the students into a state of
cognitive dissonance into an art form. This is a stand-alone workbook, with
an accompanying Instructor's Guide, providing access to many of these materials.
There is a small caveat about this workbook: some of the activities are too
simple for Canadian students.
University of Toronto Physics Practicals,
http://www.upscale.utoronto.ca/Practicals/
At the University of Toronto we have combined tutorials and laboratories
into a single entity, which we call Practicals. This is the home
page for the Practicals.
To Learn More ...
PER-Central
http://www.compadre.org/per/
The PER-Central website is provided by the American Association of Physics
Teachers.
The site is a comPADRE collection designed specifically to serve as an informational
touchpoint and online community for "producers" and "consumers" of physics education
research.
University of Maryland PER Group home page:
http://www.physics.umd.edu/perg/
This page provides access to a wealth of materials and links on PER.
Author
This page was written by David M. Harrison, Dept. of Physics, Univ. of Toronto,
in January 2010.
Last revision: $Date: 2010/01/12 19:13:04 $ (y/m/d UTC)
