Halloun, Ibrahim Abou and David Hestenes

Common sense concepts about motion

Tijdschrift/boek

American Journal of Physics, vol 53, nr 11, pp. 1056-1065, 1985.

Abstract

Common sense is a codification of experience providing meaning to our natural language. Common sense beliefs should be treated with respect by instructors, and regarded as serious alternative hypotheses.

The authors survey concepts about motion by students enrolled in physics courses by a multiple choice diagnostic mechanics test and interviews (see See Whitaker, Robert J. ). The multiple choice alternatives are classified as charateristics of either Aristotelian, Impetus, or Newtonian theories.

Nearly every student used some mixture of the theories. Students with quasi-Newtonian beliefs were far more constistent than others. The common sense conceptual systems of the students have much less internal coherence than the Aristotelian an Impetus systems. 61% confused the concepts of position, velocity, and acceleration at least once. During the interviews demonstrations/phenomena appeared to have no effect on their opinions. When a contradiction was recognized or pointed out, they tended at first not to question their own beliefs, but to argue that the observed instance was governed by some other law or priciple. The authors therefor doubt that a demonstration can be effective unless it is performed in a context that elicits and helps students to resolve conflicts between common sense and specific scientific concepts.

Student about the path of projectile: "I have been taught that it goes in a parabola, but never understood why."

Leerlingen denken vaak dat twee objecten dezelfde snelheid hebben, als ze dezelfde positie hebben.

The authors describe a briefly annotated taxonomy of the most significant common sense concepts, based on two general categories: (1) principles of motion (Newton's law of motion), and (2) influences on motion (laws of force in Newton's mechanics). A few characteristics:

The concepts of time interval and instant of time are not differentiated.

  1. Velocity is defined as distance/time, average speed is not differentiated from instantaneous velocity.
  2. Concepts of position, velocity and acceleration are not well differentiated.

One of the soltutions for these problems is to depend instructional design more on how beliefs are grounded in perception.

Annotatie

Leerlingen blijken vooral impetus-concepties te hebben.