Austin Community College Implementing Interactive Lecture Demonstrations with a Classroom Response System Paul Williams Department of Physics Austin Community College pwill@austincc.edu

Abstract Classroom response systems (CRS) provide an excellent tool for promoting active engagement in the Physics classroom.(1)  CRS’s many uses include eliciting common non-Newtonian physics conceptions by asking students to predict outcomes of experiments.  This poster will describe the author’s use of CRS to implement Interactive Lecture Demonstrations (ILD’s).  ILD’s present a sequence of related demonstrations and have been shown to be an effective way to promote active learning of physics.(2)  An ILD on Newton’s 3rd Law was adapted from Sokoloff and Thornton (3) and a second ILD on Conservation of Angular Momentum was developed by the author.  Results of various assessments will be presented.

Interactive Lecture Demonstrations Developed by Sokoloff and Thornton Present Demonstrations with a Learning Cycle Good tool for promoting active engagement and for eliciting and confronting common non-Newtonian conceptions

ILD Process Demonstration is described Demonstration is described Students predict outcome on their own Small group discussion occurs and then students predict outcome again Predictions are obtained from students Students record final prediction – Excellent application of Clickers Demonstration is carried out Students Describe the Results Comparable physical situations are elicited from students

Sample ILD – Newton’s 3rd Law Two force probes measure the forces between objects for eight different situations In each situation students were asked to predict the relative magnitude and direction of the forces between the objects

Sample ILD Task A massive cart, the truck, is pushed towards a light cart, the car, that initially isn’t moving. How does the force exerted by the truck on the car compare to the force exerted on the car by the truck.

How do the magnitudes of the forces compare? (BY) The truck exerts a greater force than the car The car exerts a greater force than the truck The forces are equal Cannot be determined 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

How do the directions of the forces compare? (BY) How do the directions of the forces compare? (BY) The directions are the same The directions are opposite Cannot be determined 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

Assessment Details Used Newton’s 3rd Law (N3L) ILD in lieu of lab activity on N3L in General Physics I ILD was given after lecture on N3L Post test consisting of 10 Questions on N3L taken from FMCE were given following all instruction on force Also examined free response question on Newton’s 3rd Law on Unit test Gave print version of ILD to section of Engineering Physics I Looked at same 10 questions from FMCE pre/post

Results from Spring, 2006 N3L Subset of FMCE GP1 Mean Correct 9.5 N3L Subset of FMCE GP1 Mean Correct 9.5 EP1 5.8 pre, 7.3 post

Knowledge Transfer An open response question concerning Newton’s 3rd Law was given on unit test Did knowledge gained in ILD transfer to a novel situation?

Spring, 2006 Unit Test Question: Ice Skater pushes on wall, identify force that accelerates the skater. Identified Force PHYS 1401 (N = 18) PHYS 2425 (N = 13) Reaction force to student pushing on wall 10 8 Student pushing on wall 5 2 Static Friction 3 Force between objects

Summary of Knowledge Transfer Students had difficulty in identifying the reaction force as the force that accelerated the skater A task was added to the ILD for students to identify the reaction force as a force which accelerates an object Modified ILD was given in Summer, 2006 Session to Section of General Physics I

FMCE Post Test Results from Summer, 2006 Mean Correct: GPI = 7.8 N = 24

Summer, 2006 Unit Test Question: Ice Skater pushes on wall, identify force that accelerates the skater. Identified Force PHYS 1401 (N = 23) Reaction force to student pushing on wall 18 Student pushing on wall 3 Static Friction 1 No force Identified

Conclusions Addition of task of identifying reaction force as accelerating force seemed to improve student performance on unit test item from 56% to 78% Performance on drawing free body diagrams and identifying action/reaction pairs as equal in magnitude but opposite in direction seemed largely unaffected

Conclusions (cont.) Performance on 10 question subset of FMCE is comparable between clicker and pen and paper versions of the ILD and is comparable to published results Plan – will give modified ILD to GPI section in Fall 2006, to investigate if improvement on performance of identifying reaction force as force that accelerates an object persists

ILD on Conservation of Angular Momentum Consists of 4 tasks on rotating stool, 2 tasks with bicycle wheel gyroscope, and 2 tasks combining rotating stool and bicycle wheel gyroscope Students were asked to predict effect of changing either moment of inertia or angular momentum of one part of system on rotational motion of the system

Results Assessment consisted of test item on final asking students to predict and explain effect of rotational motion of student on a frictionless rotating stool when arms are extended 100% predicted that angular velocity would decrease and 100% realized moment of inertia increased but only 38% combined that with conservation of angular momentum to explain decrease of angular velocity

Conclusion ILD as currently written seems to effectively instruct students in effect on rotational motion due to changing moment of inertia but does not seem to address importance of conservation of angular momentum Plan – Will modify ILD to include events on rotating stool with an external torque such as increasing angular velocity even though arms are extended

References 1.  Duncan, Douglas, Clickers in the Classroom, Addison Wesley, 2005, pp. 35-38. 2.  Sokoloff, D.R., and Thornton, R.K., "Using interactive Lecture demonstrations to create an active learning environment," The Physics Teacher, 35, 340-346, (1997) 3.  Sokoloff, David R. and Thornton, Ronald K., Interactive Lecture Demonstrations, Wiley, 2004.