NATIONAL SCIENCE DAY February 28, 1928:   His discovery of the RAMAN EFFECT: He discovered on this day that when light traverses a transparent material, some of the deflected light changes in wavelength; this phenomenon is now called Raman scattering (the inelastic scattering of a photon upon interaction with matter) and is the result of the Raman effect. Consequently, this day is celebrated as NATIONAL SCIENCE DAY in India.