Traditional vs. Problem Based Approaches to Teaching Introductory Physics 2001 Science Educators’ Conference. David P. Wick Clarkson University Acknowledgements: Michael W. Ramsdell
David P. Wick
Acknowledgements: Michael W. Ramsdell
[i]American Association of Physic Teachers, "Goals of the Introductory
Physics Laboratory," Am. J. Phys. 66, 483-485 (1998).
Outstanding challenges for the scientific community are to: the development of
- Identification of student misconceptions.
- Development of pedagogical strategies to provide a
more effective learning experience for students.
- Assessment of educational approaches.
Student difficulties are not reflections of “stupidity”, but rather deeply rooted and seemingly logical consequences of perception reinforced with personal experience.
Aarons, A. B.,Teaching Introductory Physics, John Wiley & Sons (1997).
Question: Do these two balls ever have the same speed?
Study: 300 student interviews at University of Washington
(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
“same speed” with “passing” or “same position.”
McDermott, L. C.,“Research on Conceptual Understanding in Mechanics,” Phys.
Today, 37, 24-32 (1984).
Question: A ball is thrown vertically upward from ground level
with an initial speed vo. The ball reaches a maximum
height d and returns to ground level. Which statement
43% A) The initial velocity is equal to the final velocity;
32% B)The average velocity for the entire flight is zero;
9% C) The acceleration on the way down is greater than the
acceleration on the way up;
16% D) The average acceleration for the entire flight is zero.
Study: 500 student responses at Clarkson University – Exam I
(calculus-based physics course).
Misconceptions: “Velocity” and “Speed” are interchangeable.
Acceleration depends on direction of motion.
“Understanding the way students and scientists think is the key to developing more effective methods of science teaching and is itself an intellectual challenge.”
Reif, F.,“Scientific Approaches to Science Education,” Phys. Today, 39, 48-53 (1986).
Redish, E.,“New Models of Learning and Teaching,” Conference of Physics Department Chairs (1997).
A typical first-exam grade distribution in accept a scientific concept if:Physics I at Clarkson University:
The bi-modal nature is indicative
of a well prepared and an ill
Typical Laboratory Manual Contains:
Apparatus – Description of equipment
Introduction – Theory, figures, equations
Procedure – Step 1, Step 2, …
Tables and Graphs, etc.
- Formulate verbal models
- Develop mathematical models (theoretical and numerical)
- Design experimental procedures
- Test the predictive capability of their models.
“Modeling is the name of the game in the Newtonian
Hestenes, David,“Modeling Games in the Newtonian World,”
Am. J. Phys. 60, 732-748 (1992).
Hake, Richard,“Interactive Engagement vs. Traditional Methods,”
Am. J. Phys. 65, (1995).
Develop a theoretical model describing the motion of a MatchboxTM 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.
Facts: accept a scientific concept if:A typical MatchboxTM 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.
Drag Force Model
Case by Case Assumptions accept a scientific concept if:
Case Agravitational potential andkinetic energies
Case Bsliding friction
Case Ctrack shape
Case Dair resistance
This multi-level approach illustrates how each successive stage in model development provides a correction to the previous one.
Measuring friction and air drag
We can extract values for and kby measuring
the velocity of the car at different points along a flat,
horizontal track using a series of photogates.
0.049 (No Shield)
k=1.48 x 10-4(kg/m) (No Shield)
Goal:Predict where your car will first come momentarily to rest.