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LIFE IS COLOURFUL

   

     We are enchanted by red sunset, Blue-sky, white water falls, green tea estate.  What is color actually?  We know, light is origin of color.  We also know light is electromagnetic wave.  The wave's characteristics are wavelength and frequency.  Each color is electromagnetic wave with certain range of frequency.  For example, blue light has frequency range-610-670 T Hz.
     The sun burns and emits light.  It emits characteristic seven colors as indicated by rainbow.  Sodium burns in sodium lamp and emits yellow light.  Neon gives out blue light.  Argon-red.  Each element gives out its own signature color or colors called spectrum.
     White light is a mixture of colors.  It split into constituent colors when sent through prism.  We also get Rainbow due to prismatic effect of raindrops.  Some times, when light waves meet, some colors are destroyed and some other colors are reinforced (interference of light).  This is what happens in soap bubble, oil film on wet surface and DVD.  The leaves look green and your shirt looks yellow, because all other colors in the sunlight is absorbed by leaf and shirt except green or yellow.  In the same way Red and green color filter (glasses) are used to view 3D images.
     Black is not a color according to physics.  It is absence of light.  A black object absorbs all light and gets heated quickly.  Black body gave birth to modern physics.
     Red, green and blue (RGB) is said to be primary colors (based on eye's perception).  One can create million shades of colors using just three colors.  Today, we have RGB Laser projection system in cinema theaters.  A single RGB LED bulb emits many of colors and several scenes.  RGB is also basis for an artist.  Today all screens, smart phones, laptop, LED projection-all works on the principle of RGB.  A picture is made up of many pixels (points).  Each pixel require two information.  1. Co lour (RGB) info. 2. brightness info.
    Red is used to indicate danger.  Since it can pass through long distance.  During sun set, only red light pass through, all other colors get destroyed.
    A chameleon changes color and mingles with environment to escape from enemies.  A whale's top is black but the bottom is white.  When you look from the above, it will not be visible.  When ocean beings looks from the bottom, it will not be visible again. A clever idea.

     To split composite light (white light) into colors, we have two devices.  One is prism based on dispersion of light and the other is 'grating' based on interference of light.  We cannot go near a star in our life time.  But we can receive light from it.  That light is split into colors by a device.  That spectrum of colors give us wealth of information about the star.
    If you have color pigment-melanin in your skin, you are colored.  In the absence of pigment, the skin is white and red blood gives the color. Colored skin have some advantages.
    Next time,when you see a red sun set on blue sea.  Appreciate nature and forget science for a moment.   
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