New Perspectives in Science Education

In junior high schools in Japan, first graders study convex lenses, learning that the distance between the lens and an object is closely connected with its image. In order to help students to understand this phenomenon, the drawing method is used in junior high school, but it is pointed out that learning by the drawing method does not necessarily lead understanding the properties of the convex lens itself. In order to determine the misconceptions occurring as a result of the drawing method used in junior high school lens lessons, we used the naive concept survey method, studying 104 university students in Japan (36 in the Faculty of Sociology and 68 in the Faculty of Science and Engineering). This investigation asks what kind of path the incident light to the convex lens follows when passing through the lens, and the questions are as follows: [1] "Refract only when incident light is incident on the lens", [2] "Refract only at the center line of the lens ", [3] "Refract twice at the time of incidence and exit from the lens", [4] "Refract only at exit", and [5] "Not applicable to [1] to [4]", and [3] is the correct answer. As a result of the survey, the number of students who selected the correct answer [3] is 33 (32%); while, on the other hand, 62 (60%) selected the wrong answer [2]. And this result shows many university students have misconceptions concerning the path of an incident light through a convex lens. By examining the descriptions of the students after the survey, regarding their understandings of the lens, it was found that their misconception might be caused by the influence of the drawing method used in lessons in  junior high school. Even if the position and size of the image can be drawn correctly, it is a simple mechanical drawing, and it is clear that the students could not understand the properties of the lens through the phenomenon of refraction which plays an important role in the study of optical lenses.

Keywords: misconception, convex lens, secondary school, teaching method;

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