By TFL Mawlong
National Science Day is observed every year on February 28. This article is dedicated to the scientist par excellence Dr CV Raman and to those that continue to pursue science as a subject of study that excites the mind and not burdens it.
Let us picture a batsman wagging his bat forward and backward incessantly, and a ball is bowled at him. If the bat is moving backward, along direction of the ball, at instant of contact between the ball and the bat, there will be incremental increase in velocity of the ball. In like manner, one can picture that when light particle (or photon) hits the revolving electron in an atom there will be an incremental increase or loss in energy of light particle depending upon whether at the moment of contact the electron moves along the direction of movement of light particle or in opposite direction. The light particle of increased or decreased energy constitutes the ‘new type of light’ different from incident light beam. This was how Sir CV Raman used to explain Raman Effect to the school children and the public. (Of course this is an oversimplified and flawed analogy but it does serve the purpose of popularizing science). And it is said that after listening to Raman’s explanation about his discovery his aunt remarked: “I didn’t know it was so simple. I am surprised that such simple things should have merited international recognition”.
CV Raman passed the Financial Civil Service examination in 1907 and worked as Deputy Accountant General in Calcutta. Though a government official, his interest in science did not wane. He was an ‘efficient Officer’ during the day and a ‘passionate Scientist’ in his leisure time.
It was in 1921 on his return from Europe that Raman’s scientific mind was tickled by the blue color of the Mediterranean Sea. A natural ‘childlike curiosity’ in Raman propelled him to question and to critically think about the blue color of deep sea. In those days it was thought that reflection of light is the cause of the blue color of oceanic waters. But the scientific temper in CV Raman refused to readily accept the existing theories and opinions unless he could fairly convince himself. So in that voyage, with his ‘Prism’, he observed the waters and was convinced that reflection could not possibly be the only reason for the blue color of deep seas.
Back in Calcutta he began studying the scattering of light from various chemical substances. When light beams pass through a substance, a ‘small fraction’ of the beam goes shooting off in a new direction – this is called scattering. And CV Raman discovered that ‘a small fraction’ of this scattered light beam has energy (or color) different from the incident light. This small fraction of scattered light whose energy is different from that of incident light is the ‘new type of light’ (or the new induced radiation) coming out of the medium. When light is scattered by the water molecules, the ‘new type of light’ has energy in the blue end of the spectrum more than in reds and yellows, hence deep sea appears blue. This phenomenon came to be known as the ‘Raman effect’.
The essence of Raman Effect is that the energy of scattered light (or the ‘Raman pattern’) depends on the type of molecules of the substance. This means different substances have different Raman patterns, just like people have different fingerprints. One can therefore say that the Raman Effect ‘fingerprints the universe’. It helps in the ‘identification of substances’ just like fingerprints identify humans. Today the Raman scanners that detect the molecular structure of objects they are scanning are being used in Airport and Narcotic squads to detect drugs; by security experts to detect explosives; by police force in forensic work; and in medical science to detect pathogens. Researchers in Stanford University are busy experimenting with Raman scanner to detect cancer and in comprehensive blood tests. In short, Raman Effect enables us to instantly recognize everyday substances and to determine if the substance is RDX or TNT, heroin or chalk, glucose or cholesterol, etc, even if the quantities are present in minute quantities.
Beyond the ‘finger-prints of the universe’ there are other subtle things to learn from the life of CV Raman. Our thinking of science education has always been limited merely to measuring electric current, deducing an equation, dissecting a china rose or shaking the test tubes within our school walls. We look at science as merely about technical know-how or productivity. But, beyond the technical know-how, science literacy is also about the ability to make sense of the world around us, to be curious and to critically think about ideas and events we encounter in everyday life. In fact it is this curiosity, adventure and a child-like sense of wonder that prompted an Indian Physicist, CV Raman to ask the question: “Why the deep oceans are blue?” He couldn’t have thought that this simple question would have a far reaching effect in modern science.
Perhaps as we celebrate the National Science Day we should ask, what are we doing in the classrooms and campuses to instill curiosity and the spirit of scientific inquiry in students? As things stand now, in our schools and colleges, science is being naively and stodgily presented like it is a hotchpotch of arbitrary rules. To say the least, science education in our city is incomprehensible, too bookish and dangerously misdirected – instead of giving emphasis on analytical thinking and basic understanding of the subject our science education has been measured by how well we can recall or how well we can reproduce the dictated notes in the exam.
It is rather unfortunate to see our classrooms get redefined as ‘note dictation exercise and rote learning’. Besides, our board and university exams have degraded into a ‘pointless and worthless torturous exercise’ for the students. In my personal opinion, the ‘science teaching in our city’ is a ‘thing of great shame’. We train the students to be mere stenographers, rather than thinkers. So I don’t think it is an exaggeration to say that our traditional science education system describes an unmistakable journey that makes students navigate through the blur, towards an uncertain future. If you score 40% percent in science then you are ‘science-unworthy’ because, you couldn’t reproduce the notes your teacher dictated, or couldn’t reproduce the text book definitions or derivations verbatim. But a crammer who scores 90+ %, is considered the ‘wizard of science’ or the ‘wizard of mathematics’, even if he may have neither the basic understanding of the subject nor any analytical thinking ability. If I may add, our board papers and even the honors level university papers (science) test neither the analytical thinking of students nor the command a student has on the subject. Then, many of these high score-crammers get to join the schools or colleges as educators (pseudo-educators) and a vicious cycle continues. See, the thing is, with this ‘culture of giving notes’ in our classroom (which is nurtured by our worthless examination system), we aren’t just ‘spoon feeding’ our students, we are ‘breast feeding’ them lest they fail to score in exam, lest the institution looks bad, lest the institution reports looks dull, and so on. But, as Einstein Said, “if we are spoon feeding our students, the only thing they’ll ever learn is the shape of the spoon”.
Through our annual National Science Day, may the life of Sir CV Raman encourage a ‘curiosity-based-learning’ and a ‘great-science-teaching’ in our educational institutions.
(The writer is an alumnus of IIT Kanpur)