Traditional vs. Problem Based Approaches to Teaching Introductory Physics 2001 Science Educators’ Conference David P. Wick Clarkson University Acknowledgements: Michael W. Ramsdell Acknowledgements: Michael W. Ramsdell Joseph Hruska Joseph Hruska

A Set of Goals Established by the American Association of Physics Teachers A strong program should emphasize experiential learning, open-ended problem solving and development of analytic and collaborative learning skills. A strong program should emphasize experiential learning, open-ended problem solving and development of analytic and collaborative learning skills. Students should have the opportunity to experience all aspects of scientific analysis including the design, development and execution of a successful experimental investigation. Students should have the opportunity to experience all aspects of scientific analysis including the design, development and execution of a successful experimental investigation.

Students should have access to experiences that encourage the development of verbal and mathematical models used to mimic the natural world. Students should have access to experiences that encourage the development of verbal and mathematical models used to mimic the natural world. A strong program should provide exposure to experimental, theoretical and numerical development, allowing students to truly master a variety of basic skills in problem solving and data analysis. A strong program should provide exposure to experimental, theoretical and numerical development, allowing students to truly master a variety of basic skills in problem solving and data analysis. [i][i] American Association of Physic Teachers, "Goals of the Introductory [i] Physics Laboratory," Am. J. Phys. 66, (1998). Physics Laboratory," Am. J. Phys. 66, (1998).

Outstanding challenges for the scientific community are to: Outstanding challenges for the scientific community are to:  Find innovative methods for achieving these goals.  Develop tools for assessing the performance of our students and the effectiveness of our methods.

Physics Education Research is a work in progress… PER has logged over three decades worth of scientific investigation with attention given to: PER has logged over three decades worth of scientific investigation with attention given to: - Identification of student misconceptions. - Identification of student misconceptions. - Development of pedagogical strategies to provide a - Development of pedagogical strategies to provide a more effective learning experience for students. more effective learning experience for students. - Assessment of educational approaches. - Assessment of educational approaches.

Misconceptions or Preconceptions? Student minds are not blank slates. Student minds are not blank slates. Many students defend their beliefs from the high seat of experience. Many students defend their beliefs from the high seat of experience. Student difficulties are not reflections of “stupidity”, but rather deeply rooted and seemingly logical consequences of perception reinforced with personal experience. Student difficulties are not reflections of “stupidity”, but rather deeply rooted and seemingly logical consequences of perception reinforced with personal experience. [2] Aarons, A. B., Teaching Introductory Physics, John Wiley & Sons (1997). [2] Aarons, A. B., Teaching Introductory Physics, John Wiley & Sons (1997). [2]  Examples are well documented.

Example: The Concept of Velocity Ball A Ball A Ball B Ball B Question: Do these two balls ever have the same speed? Study: 300 student interviews at University of Washington (calculus-based physics course). (calculus-based physics course). Misconception: The balls have the same speed at the moment one 40% passes or is next to the other. Students associate 40% passes or is next to the other. Students associate “same speed” with “passing” or “same position.” “same speed” with “passing” or “same position.” [3] McDermott, L. C., “Research on Conceptual Understanding in Mechanics,” Phys. [3] McDermott, L. C., “Research on Conceptual Understanding in Mechanics,” Phys. [3] Today, 37, (1984). Today, 37, (1984).

Example: Velocity vs. Speed Question: A ball is thrown vertically upward from ground level Question: A ball is thrown vertically upward from ground level with an initial speed v o. The ball reaches a maximum with an initial speed v o. The ball reaches a maximum height d and returns to ground level. Which statement height d and returns to ground level. Which statement is TRUE? is TRUE? 43% A) The initial velocity is equal to the final velocity; 43% A) The initial velocity is equal to the final velocity; 32% B) The average velocity for the entire flight is zero; 32% B) The average velocity for the entire flight is zero; 9% C) The acceleration on the way down is greater than the 9% C) The acceleration on the way down is greater than the acceleration on the way up; acceleration on the way up; 16% D) The average acceleration for the entire flight is zero. 16% D) The average acceleration for the entire flight is zero. Study: 500 student responses at Clarkson University – Exam I (calculus-based physics course). (calculus-based physics course). Misconceptions: “Velocity” and “Speed” are interchangeable. Acceleration depends on direction of motion. Acceleration depends on direction of motion.

We must eliminate misconceptions, but students will only accept a scientific concept if: They understand the concept. They understand the concept. It is believable. It is believable. It is useful. It is useful. It conflicts with their current beliefs. It conflicts with their current beliefs. “Understanding the way students and scientists think is the key to developing more effective methods of science teaching and is itself an intellectual challenge.” “Understanding the way students and scientists think is the key to developing more effective methods of science teaching and is itself an intellectual challenge.” [4][4] Reif, F., “Scientific Approaches to Science Education,” Phys. Today, 39, (1986). [4]

Current Strategies: Interactive Engagement Lecture-based (Peer instruction, Interactive Lectures, …) Lecture-based (Peer instruction, Interactive Lectures, …) Recitation-based (Tutorials, Cooperative Problem Solving, …) Recitation-based (Tutorials, Cooperative Problem Solving, …) Lab-based (Projects, Problems, Simulations, …) Lab-based (Projects, Problems, Simulations, …) Combination (Physics by Inquiry, Workshop Physics, Physics Studio …) Combination (Physics by Inquiry, Workshop Physics, Physics Studio …) [5][5] Redish, E., “New Models of Learning and Teaching,” Conference of Physics Department Chairs (1997). [5]

A typical first-exam grade distribution in Physics I at Clarkson University: A typical first-exam grade distribution in Physics I at Clarkson University: The bi-modal nature is indicative The bi-modal nature is indicative of a well prepared and an ill of a well prepared and an ill prepared group. prepared group.

Traditional Laboratory Experience Typical Laboratory Manual Contains: Title Title Apparatus – Description of equipment Apparatus – Description of equipment Introduction – Theory, figures, equations Introduction – Theory, figures, equations Procedure – Step 1, Step 2, … Procedure – Step 1, Step 2, … Tables and Graphs, etc. Tables and Graphs, etc.

Current Approach: Lab/Recitation-based  Modification of the traditional laboratory / recitation to incorporate a problem based learning experience with an emphasis on open-ended problem solving.  Provide students with the opportunity to: - Formulate verbal models - Formulate verbal models - Develop mathematical models (theoretical and numerical) - Design experimental procedures - Test the predictive capability of their models.

Problem Based Learning Physics Team Design Program Problem Based Learning Physics Team Design Program Current Participation: % of class Current Participation: % of class Lecture Component – Traditional Lecture Component – Traditional Lab/Recitation Component – Problem Based Lab/Recitation Component – Problem Based “Modeling is the name of the game in the Newtonian World” World” [6] Hestenes, David, “Modeling Games in the Newtonian World,” [6] Hestenes, David, “Modeling Games in the Newtonian World,” [6] Am. J. Phys. 60, (1992). Am. J. Phys. 60, (1992).

Traditional vs. Problem Based Approaches Physics I – Modeling the Motion of a Physics I – Modeling the Motion of a Matchbox Car Matchbox Car Physics II – Modeling the Motion of an Physics II – Modeling the Motion of an Electric Train Electric Train

Assessment: Force Concepts Inventory David Hestenes (Arizona State University) and others have developed a quantitative assessment tool for checking a student's understanding of basic concepts in physics. David Hestenes (Arizona State University) and others have developed a quantitative assessment tool for checking a student's understanding of basic concepts in physics. FCI topics cover the fundamental issues and concepts in Newtonian dynamics. FCI topics cover the fundamental issues and concepts in Newtonian dynamics. FCI distractors (wrong answers) are “malicious” -- they are based on research that exploits students' most common misconceptions. FCI distractors (wrong answers) are “malicious” -- they are based on research that exploits students' most common misconceptions.

Results of the FCI are Disappointing! Richard Hake (Indiana University) conducted a study of 62 classes (6542 students) from around the country. He showed that for a wide range of initial pre-test scores, the fractional gain is similar for classes of similar instructional method. Richard Hake (Indiana University) conducted a study of 62 classes (6542 students) from around the country. He showed that for a wide range of initial pre-test scores, the fractional gain is similar for classes of similar instructional method. For Traditional classes: h ~ / For Traditional classes: h ~ / For IE classes: h ~ /-0.14 For IE classes: h ~ /-0.14 [7][7] Hake, Richard, “Interactive Engagement vs. Traditional Methods,” [7] Am. J. Phys. 65, (1995). Am. J. Phys. 65, (1995).

Force Concepts Inventory (FCI)

Team Design Produced Significantly Higher Gains Than Traditional Labs

Comparison Group? Team Design Produced Significantly Higher Gains Than a Comparison Group Comparison Group? Team Design Produced Significantly Higher Gains Than a Comparison Group

Best of the Rest? – High SAT Team Design Even Produced Higher Gains Than the High SAT Group Best of the Rest? – High SAT Team Design Even Produced Higher Gains Than the High SAT Group

Comparison Table GainSAT (Verbal / Math) Final Grade Conventional Labs (337) / C+ Team Design (54) / B+

Comparison Table GainSAT (Verbal / Math) Final Grade Conventional Labs (337) / C+ Team Design (54) / B+ Comparison Group (54) / B

Comparison Table GainhSAT (Verbal / Math) Final Grade Traditional Labs (337) / Team Design (54) / Comparison Group (54) / High SAT (54) /

Matchbox Car Project

“Modeling the Motion of a Matchbox TM Car” Problem Statement: Problem Statement: Develop a theoretical model describing the motion of a Matchbox TM car racing down an arbitrarily shaped track. Your model should describe the velocity of the car at any point along the track. (Identify the most important effects that should be included in this model). Develop a theoretical model describing the motion of a Matchbox TM car racing down an arbitrarily shaped track. Your model should describe the velocity of the car at any point along the track. (Identify the most important effects that should be included in this model). Design an experimental procedure to evaluate the predictive capability of your model. Design an experimental procedure to evaluate the predictive capability of your model.

Facts: A typical Matchbox TM car has a die-cast body, two axles, and four hard plastic wheels, with a total mass (m) of approx. 50 g. The combined mass of the wheels is less than 3 % of the total mass of the car. The plastic wheels rotate on the axle through direct contact with a sliding type motion. Air resistance can be accentuated by mounting a shield of varying area. The plastic wheels rotate on the axle through direct contact with a sliding type motion. Air resistance can be accentuated by mounting a shield of varying area.

Developing a Theoretical Model Consider the forces acting on the car: Consider the forces acting on the car: Frictional Model Frictional Model Drag Force Model Drag Force Model Applying Newton’s Second Law will allow us to develop a model for the velocity of the car. Applying Newton’s Second Law will allow us to develop a model for the velocity of the car.

Case by Case Assumptions Case by Case Assumptions Case A gravitational potential and kinetic energies Case A gravitational potential and kinetic energies Case B sliding friction Case C track shape Case D air resistance

Hierarchical Structure of Solutions Case Solution (Model) A B C D This multi-level approach illustrates how each successive stage in model development provides a correction to the previous one.

Designing an Experimental Procedure Measuring friction and air drag We can extract values for and k by measuring the velocity of the car at different points along a flat, horizontal track using a series of photogates.

Experimental Results for a Level Track (No Shield) (No Shield) k = 1.48 x (kg/m) (No Shield) k = 1.48 x (kg/m) (No Shield)

What About an Arbitrary Track?

Comparing Theory to Experiment

Sample Challenge Session Goal: Predict where your car will first come momentarily to rest. Goal: Predict where your car will first come momentarily to rest.

Electric Train Project

Model Rocket Project