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Motion Matching AChallenge

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					Motion-Matching: AChallenge
Game to Generate Motion
Concepts
David Schuster and Betty Adams, Western Michigan University, Kalamazoo, MI
David Brookes, Florida International University, Miami, FL
Marina Milner-Bolotin, Ryerson University, Toronto, Canada
Adriana Undreiu, University of Virginia’s College at Wise, Wise, VA




             otion is a topic that is taught from                    of the room and thus ―blind‖ to the original motion
             elementary grades through to university                 has to translate the descriptions back into reenacted
             at various levels of sophistication. It is              motions.
an area that can be challenging for learning in a                       The game-like aspect arises from the fact that
conceptually meaningful way, and formal kinemat-                     students’ initial descriptions are likely to be vague
ics instruction can sometimes seem dry and boring.                   or incomplete, so that attempted reenactments are
Thus, the nature of students’ initial introduction to                often hilarious but instructive, with the reenactor de-
motion is important in sparking their interest, shap-                liberately making ―wrong‖ motions from inadequate
ing their perspective, and developing conceptual                     descriptions. Each reproduction attempt leads to an
understanding of motion. The kinematic concepts                      improved description. This eventually leads students
we want students to acquire for basic motions are:                   to generate collectively the basic quantities required
position, time, speed, direction, velocity, veloc-                   as motion descriptors, in a process of successive re-
ity change, change rate, and acceleration, all with                  finement. Thus, the formal kinematic concepts men-
respect to a frame of reference. In this article we                  tioned above arise naturally, expressed informally at
describe a challenge game used as an ―opener‖ to                     first. Students ―invent‖ the ideas inductively for the
motion, in which students themselves essentially                     task at hand, rather than being ―told.‖
generate these concepts, in everyday language, from a                   Thus, in a succession of fun attempts, everyone
perceived need for them.                                             learns about basic motion types, motion concepts,
   We have used the game as an initial engagement                    and two-way translation between real motions and
activity at Western Michigan University, Rutgers                     verbal representations. It turns out that the way peo-
University, Ryerson University, and the University of                ple ordinarily describe motion verbally is in terms of
British Columbia. It has been demonstrated at meet-                  ideas much the same as the formal kinematic counter-
ings of the American Association of Physics Teachers,                parts, though expressed in everyday language, casually
and schoolteachers have tried it successfully at various             and less precisely. Appreciating the need for accurate
grade levels.                                                        description in science is another objective of the activ-
   In the activity, fun but with serious intent, one per-            ity.
son enacts a real motion in class, walking or running                   The game can be played at various levels of dif-
to produce one of a number of basic motion types                     ficulty, qualitative or quantitative, for various types of
(e.g., constant speed, speeding up, or slowing down)                 motion. We describe the first and simplest qualitative
and at various rates. Others observe and produce                     game, discuss its instructional rationale, and report on
verbal or written descriptions of the motion. This is                student and instructor reactions.
followed by the inverse process; a person who was out


        434                                 DOI: 10.1119/1.3225502                      THE PHYSICS TEACHER ◆ Vol. 47, October 2009
             Photographs showing some of the events during a game.




                    Photo 1.                  Photo 2.               Photo 3.               Photo 4.                 Photo 5.


             Motion-Matching – The First Game                              words, we have added the corresponding physics
                As noted, the essence of the motion-matching activ-        terminology in square brackets.
             ity is the translation of an observed motion into verbal           The reenactor, pointing to a selected whiteboard,
             descriptions, followed by translation of the descrip-         asks the person to call out the instruction.
             tions back into reenacted motions, in the process gen-          –“Walk slowly!” [kinematic quantity: speed]
             erating the necessary motion concepts.                             Reenactor walks slowly but starts from the
                To give a sense of how the game might operate              ―wrong‖ place in the room. Stumbles into a bench
             in class, we illustrate its ―moves‖ for Game One, the         (Photo 3).
             simplest motion with qualitative descriptions. For this
             introductory game it is best to prime a student volun-           –―No, you’re starting from the wrongplace! Start at
             teer to be ―in the know,‖ in order to take full advantage        the end of the board!” [initial position]
             of the game’s instructional potential and make sure it             Goes to the board but to the wrong end, and starts
             runs smoothly. The instructor and collaborator agree          walking from there.
             beforehand on the first motion to be enacted, i.e.,              –―That’s the wrong end! Start from the other end of
             walking at a steady speed. This game serves both to              the board!” [frame of reference; initial position]
             demonstrate what the activity is all about and at the              Goes to the correct end but then climbs up onto a
             same time start generating motion concepts.                   conveniently placed stool. Steps off it with interesting
                                                                           results (Photo 4).
                The game sequence goes as follows. The instructor             –“No, not from up there. Start on the ground!”
             outlines the nature of the game to the class, asks for           [frame of reference; three-dimensional]
             a volunteer, and leaves the room. The volunteer then
             enacts a basic first motion by walking at a slow steady            Starts at the correct spot but then walks out into
             pace alongside the board (see Photo 1) while students         the room, i.e., in the wrong direction. Thus bumps into
             observe. The instructor is then called back in (Photo         a person.
             2), available to act on instructions, and students have          –“That’s the wrong direction – go parallel to the
             about half a minute to come up with motion descrip-              board!” [initial direction]
             tions. They can write these on small whiteboards. (It             Stands at the correct spot, facing along the board
             enhances the game atmosphere if someone whistles or           ready to walk, hesitates...and then walks backward.
             plays the ―Final Jeopardy‖ theme tune from the TV                – ―Silly, not backward! Walk forward this time!”
             quiz show while students write).                                 [initial direction; reference axis]
               The instructor has some control of how the game                 Starts by walking forward but thereafter takes a
             now goes by selecting from the descriptions offered           wandering path.
             and deciding which to act on first, ready to pounce              – “No, not curvy ... walk in a straight line all the
             on inadequacies by deliberately enacting ―wrong‖
             motions allowed by the description. The events or
             ―moves‖ in any game will vary depending on class re-
             sponses, but below we illustrate the kind of sequence
             and dialogue one hopes for in students’ first
             encounter with the activity. After the students’ own


THE PHYSICS TEACHER ◆ Vol. 47, October 2009                                                                 435
   time.” [straight-line motion]
    Walks in a straight line in the correct direction...         Game notes and teaching strategies
but speeds up along the way.                                   There are various teaching strategies and caveats that can
   – “No, don’t speed up – walk at a steady speed all the      help make the activity work well and achieve its goals.
   time.” [constant speed]                                           Note that this activity is clearly a game, so it is natural
    Walks at constant speed—but much too slowly.              for it to seem somewhat contrived. For the same reason one
                                                              can happily “overplay” the game events to make the point.
   –“You’re going too slowly ... move faster.” [speed
                                                              Students also tend to enjoy giving instructions to the instructor.
   magnitude; qualitative]
                                                                   As the class produces descriptions and refinements, stu-
    Walks again but much too fast this time.
                                                              dents can put up their whiteboards sequentially at the front of
   – “Not so fast! You’ve overdone it. Move at...um...        the classroom. It is also useful to have a student write up the
   medium walking pace.” [speed magnitude, refined]           sequence of specifications as a list on the board as they arise.
    The reenactor moves ―correctly,‖ fully constrained        These will generally be in everyday language but in addition can
                                                              be labeled with the scientific term, e.g., initial position, etc.
now.
                                                                    There is a danger, as with any activity, that fun aspects
    –“That’s it ... finally!” [accumulated descriptors all    and practical details can obscure the real purpose, unless
    in play]                                                  one keeps the underlying objective uppermost. Accumulating a
                                                              list of descriptors helps with this.
   The reenactor has no more ―wiggle room‖ and must
move as specified by the accumulated description re-                The activity, even with successive refinements, goes rap-
                                                              idly in class; students catch on quickly and descriptions
finements, i.e., from the designated initial position,
                                                              soon become tight enough to ensure faithful reproduc -
in the correct direction, in a straight line, at constant     tion. There is no need to belabor points during the game.
specified speed, all relative to a specific frame of refer-
                                                                   Note that since the class soon realizes what the reenactor
ence.                                                         is up to, a variation part way through is to let them in on it and
   The criterion for success is that the original motion      ask: “OK, what do you think I’m going to do next (to foul up)?”
enactor must agree that the reenacted motion matches               In principle the reenactor could be blindfolded instead of
the original. This is more dramatic if done by direct         out of the room, but this would preclude the class talking about
comparison: enactor and reenactor act out their mo-           the enacted motion during that time.

tions simultaneously side by side (Photo 5). For effect
we play or whistle ―Pomp and Circumstance‖ during
this ―matching march.‖
    For each motion, before going on to the next, it
is important to reflect on the concepts that arose and           There are two parallel challenges in the game: how
what has been learned and how. We want the ultimate           to characterize motions, and how to describe them
message to be the motion concepts, not just the game          precisely in words. It is fortunate when experiential
events. One can also ask the students to write down           notions correspond roughly to formal science con-
three things they didn’t understand well beforehand           cepts, and when everyday vocabulary roughly fits for-
and three insights gained.                                    mal terminology. This is not always the case in science,
                                                              but for motion, students’ existing ideas are clearly
   The activity represents an inquiry-based inductive         resources to be built on.
instructional approach. By contrast, in a ―direct‖ ap-
proach an instructor simply tells the students that mo-          It turns out that the way people ordinarily think
tions are characterized by specified kinematic quanti-        about and describe motions corresponds reasonably
ties. The concepts are received rather than generated.        well to the desired scientific concepts and terms,
   We note that inquiry-based instruction is advocated        though expressed less formally and precisely. The game
by national and state science education standards             highlights how difficult it can be to describe things
throughout K-12 schooling. At college level a number          well, and the need for precision and completeness in
of reformed approaches to science instruction take            science. One can mention to students that other rep-
inquiry approaches, many stemming from physics                resentations such as graphs or equations can provide
education research.1-6                                        precision, as they will see later.



         436                                                                        THE PHYSICS TEACHER ◆ Vol. 47, October 2009
            Subsequent Motion Types and Game                                  The motion-matching activity involves a variety of
            Levels                                                         other ideas relevant to motion. At suitable times, or
               For the initial demonstration game described above,         on reflection, one can explicitly direct attention to is-
            the instructor usually plays the role of reenactor. For sub-   sues such as:
            sequent games and different motions, students take over             Point particle representation
            and run the activity, playing all the roles themselves.             Interval quantities and a differential perspective
               After the first game there are two ways to move to                 on motion
            the next level: either go on to motions with changing               Rates of change
            speed, still done qualitatively, or make the steady mo-             Qualitative and quantitative descriptions
            tion case quantitative. One can do these in the order               Everyday and scientific language.
            in which students seem to head of their own accord.               Thus, this apparently simple game provides many
            These cases are described briefly below, as well as com-       teachable moments by injecting such ideas at the ap-
            plex motions and other relevant concepts.                      propriate time. Each is worth discussing in its own
                                                                           right to an extent that depends on objectives. One can
            Accelerated motions – qualitative games
                                                                           also play a ―custom‖ game focusing on one particular
               If one stays in qualitative mode and tries different        aspect, position-location for example.4
            motions, subsequent games then involve variants of
            the first (i.e., different starting points, directions, and    Student and Instructor Reactions
            speeds) followed by accelerated motions (speeding up
            or slowing down). For speeding up, an enactor would               Student and instructor reactions to the activity
            start from rest and speed up to a run, gradually and           have generally been very favorable. Below we give
            continuously. For slowing down, an enactor would               some reactions from Physics 1800, a course for pro-
            already be running at the initial spot and then slow           spective elementary teachers at Western Michigan
            down continuously to a stop (or even reverse). In de-          University.
            scribing such motions, students add the concepts of               A written survey asked students to comment on the
            speed change and change rate to their previous set of          activity and say how well they thought it succeeded as
            motion descriptors.                                            an opener to motion. Of 40 students in two sections,
                                                                           32 had positive comments only, six had mixed com-
            Quantitative game levels                                       ments, one had a negative comment only, and one did
               A qualitative game can move up a level by becom-            not respond. Some brief extracts from comments are:
            ing quantitative. Relevant quantities are then speci-          Some positive comments: ―I enjoyed the activity, it was
            fied numerically, in units suited to the situation. In         interactive...everyone seemed interested and engaged.‖
            principle there are two ways of specifying a motion            ―It was something I’ve never done before...I never
            quantitatively. One is to specify pairs of position-time       would have thought that is so hard to explain.‖ ―Made
            values, while another is to focus on intervals and refer       me realize what concepts are related to motion, what is
            to differential quantities (speed and acceleration) dur-       required to describe motion scientifically.‖ ―What types
            ing the motion. It is interesting that our students tend       of motion there are.‖ ―Got the whole class involved and
            toward the latter.                                             actually laughing.‖ ―Everyone learned a lot while having
                                                                           fun.‖
            Complex motions
               From the instructor’s point of view, the few basic
            motion types above form a sensible sequence for pro-           Some negative comments: ―Too simple...good for
            moting the learning objectives. However, note that             elementary students, a little redundant for college.‖ ―Too
            students will soon want to indulge in fun with com-            long...activity could be shorter.‖ ―Annoying, because the
                                                                           teacher tried as hard as he could to do the wrong things.‖
            plex and even acrobatic motions. They enact dancing,
                                                                           Commenting as future teachers: ―Fun for young kids...
            twirling, and multi-stage motions as they get into the         they would enjoy giving directions to their teachers,
            swing of things. Toward the end of one session, an             because they don’t ever get to be the one giving
            imaginative student walked on her hands and students           directions, it is always the teacher.‖ ―A bit difficult for
            drew hand outlines in chalk on the floor to indicate           younger kids
            what the reenactor should do!
            Teachable moments for other relevant concepts



THE PHYSICS TEACHER ◆ Vol. 47, October 2009                                                                   437
 perhaps?‖ ―Yes, an activity I would use in teaching.‖        not thought of. Photography is by Mike Lanka
    A physics teacher who had seen our conference             at Western Michigan University. Course develop-
 demonstration tried the game at her own high school          ment was supported in part by National Science
 and emailed that the idea had come at just the right         Foundation grant DUE 0536536 and a seed grant
 time for starting motion and had been a ―smash hit‖ at       from the Michigan Space Grant Consortium. Any
 her school. Of course, as with any participatory activ-      opinions, findings, conclusions or recommendations
 ity that depends on class dynamics, it will work better      in this paper are those of the authors and do not nec-
 on some occasions than others.                               essarily reflect the views of the grantors.

 Conclusion                                                   References
    Motion-matching is an engaging game that can be           1.  E. Etkina and A. Van Heuvelen, Investigative Science
 used as an ―invitation to learn‖ when starting motion.           Learning Environment (ISLE); http://www.islephysics.
 At the risk of sounding trite, we can say that the activ-        net and http://www.rci.rutgers.edu/~etkina/ISLE.htm.
 ity is both hands-on and minds-on.                            2. Arnold B. Arons, The Various Language (Oxford Univer-
                                                                  sity Press, New York, 1977).
    We find that people tend to describe observed mo-
                                                               3. L.C. McDermott and the Physics Education Group at
 tions in everyday language in terms of perceptually              the University of Washington, Physics by Inquiry (Wiley,
 evident features that correspond quite closely to the            New York, 1996).
 desired scientific concepts of reference frame, initial       4. W. J. Leonard, R. J. Dufresne, W. J Gerace, and J.
 position, direction, speed, speed change, and rate of            P. Mestre, Minds-on Physics: Motion (Kendall/Hunt,
 change (acceleration). This intuitive tendency can be            Dubuque, IO, 1999), Activity 2A.
 seen as a resource to build on in instruction.                5. Priscilla W. Laws, Workshop Physics: Activity Guide Mod-
    It is interesting that, from a mathematical perspec-          ules, 2nd ed. (Wiley, Inc., New York, 2004).
 tive, both velocity and acceleration are differential         6. David Schuster, Mechanics, Inquiry and Insights, Physics
 quantities (being rate of change of position and rate            course pack (Western Michigan University, 2004).
 of change of velocity, respectively). This also seems to      7. R.W. Bybee et al., Science and Technology Education for
 reflect what people notice when they observe actual              the Elementary Years: Frameworks for Curriculum and
 motions: how things are changing.                                Instruction (The National Center for Improving Instruc-
                                                                  tion, Washington, DC, 1989).
    Note that motion-matching is envisaged as an              PACS codes: 01.55.+b, 45.00.00
 ―overture.‖ For science instruction that explicitly uses a
 learning-cycle approach, such as the 5-E cycle,7 it can           David Schuster is an associate professor in physics and
 serve as a wonderful Engage phase, with a good admix-             science education at Western Michigan University.
 ture of Explore and Explain aspects as well. However it           david.schuster@wmich.edu

 need not necessarily form an integral part of the ―main           Marina Milner-Bolotin is an assistant professor in the
 movement‖ conceptual development sequence. After                  Department of Physics at Ryerson University in Toronto.
 the overture, we go to our planned kinematics teach-              mmilner@ryerson.ca
 ing sequence, which the game complements.                         Betty Adams is an engineer working on graduate degrees
   The challenge game works well in both small classes             in physics and science education at Western Michigan
                                                                   University. b.adams@wmich.edu
 and large lectures, can be adapted to a range of levels,
 and can be used in both science courses and teaching              David Brookes is an assistant professor in the Physics
 methods courses.                                                  Department at Florida International University.
                                                                   dbrookes@gmail.com

 Acknowledgments                                                   Adriana Undreiu is a teaching fellow in the natural sci-
                                                                   ences department at the University of Virginia’s College at
 The authors would like to thank Bill Merrow, whose                Wise and is completing her doctorate in science educa-
 toy car activity sparked a train of thought; Eugenia              tion.
 Etkina, who does her own version of the game at                   au8e@uvawise.edu
 Rutgers; Philip Kaldon, who spontaneously whistled
 the two theme tunes during a game; and our many
 students, who came up with good ideas we had


438                                                                     THE PHYSICS TEACHER ◆ Vol. 47, October 2009

				
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