MODELLING AS A TECHNIQUE TO AID ALTERNATIVE CONCEPTIONS IN PHYSICS

A case study was conducted taking a group of 27 class 12 students of DMS, Bhopal to explore the effectiveness of modelling technique called ‘Tractor vs. Car and Tall man vs. Child' as a classroom technique to help students form alternative conceptions about abstract concepts in physics. An attempt was made to look at the existing refraction and dispersion related concepts of the students through iterative inquiry approach. The conceptions of students about dispersion were explored through a series of inquiry questions like: what is dispersion? What is the sequence of appearance of colours on the screen after dispersion of white light by a prism? What are the probable reasons for such appearances of colour? What may be the basic causes of dispersion? What are the laws of refraction? Do they find situations in their daily life similar to refraction? Though students had already studied the concepts, still most of them could not comprehend reasonable and logical answers to most of the questions. At best they could recall some stray answers which they could not defend when cross fired with counter questions. Later on a modelling technique called ‘Tractor vs. Car and Tall man vs. Child' was introduced to help students form alternative conception about the phenomenon called refraction and dispersion. Daily life situations like students in play ground, students exiting from school as the last bell goes, a car obliquely entering a patch of sandy road from concrete path were part of modelling techniques used in class. This enabled all students to form concepts like what happens to the direction of path of light when it travels from rarer medium to denser medium and vice versa; most of them could demonstrate their understanding through reasonable and logical answers to all sorts of critical counter questions.