Experiences

Bending of the light

Mária Dojčanová

Slovakia

High Secondary School

Physics

Teaching in class

Direct

The aim of the lesson was to show and prove to the students that light, seen as electromagnetic waves, is capable of bending, which produces an interference pattern.
Because the concept of mechanical bending of waves pupils already know from previous classes, I try to rehearse the bend wave conditions with the pupils, and induce to repeat the situation when light as electromagnetic waves is also capable of bending. Together we repeat that bending waves occurs at the obstacles of small size - small hole - eg. gap, thin object - eg. thin wire. Because experiments raise the interest and attention of students, I use a slit or double slit to sample the bending of light. The presented slit is made up of a razor blade (two knives side by side) in a black film lit used in the camera and the red laser beam. Enclosing the laser to the slit (or double slit) the interference pattern is reproduced on the screen, for example a wall. After the demonstration, pupils really like to try the experiment by themselves.
After this experiment, the pupils can see very good examples of bending light on the narrow slit or a small circular hole in the digital textbook of physics by PaedDr. Joseph Beňuška. I use this literature in my physics classes quite often. At the same time they write in their workbooks own notes and make drawings from the digital textbook illustrations of the phenomenon. Such educational presentations help students confirm and remember the findings. The positive side of educational presentations is that the students have the phenomenon yet again in demonstration in writing after they just made the experiment and to me as a teacher this saves the lesson time. Therefore I do not have to write and draw everything and can focus more on students and other class activities.