Monday, December 30, 2013

What they do not teach you at school?

Last June, I was on a short trip to my hometown, Jamshedpur. In my wee hours of the day, I checked my niece Shreya's progress on her academics. She will be appearing in her standard 10th board exams in 2014.

Our discussions spun around optics/refraction of light.

Almost all the textbooks of class 10 physics will suggest something similar to this ray diagram on bending /dispersion of light through a prism.

In order to assess her conceptual know how of optics, I posed following 2 questions to her:
  1. Why do light rays bend?
  2. Will the above ray diagram be always true?
What followed was a numb eerie silence. 

To highlight the problem here, our academics system has turned into parochial system. Students are expected to read and mug up the text book without any understanding of the concepts.Students lack the analytical skills on turning the text book concepts into practical insights. IMO, Grades/CGPA/GPA doesn't matter much when it comes real world.

None of Shreya's teacher had taught her that:

  1. Like electrical energy and heat energy , light is also a form of energy. And, like electrical properties ( resistance) and  thermal properties (specific heat), refractive index is also a 'resistance' property of a medium prevalent only for light energy.
  2. When light travels from lighter to denser media, it bend towards the normal and vice versa. This is a powerful assertion. The above ray diagram 'assumes' light traveling from lighter ( air/vacuum) to denser medium (glass) and will not be true if the medium on the left hand side is denser than the prism refractive index.

Wish this changes soon.

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