This is one of the series of the articles specifically written
for those who had not studied science at all. This would also be useful who had
studied science but not too much detail or have forgotten what they read. To
meet this goal we will not use and large technical jargons or complicated
theories and calculation.
COLOURS- HOW AND WHY
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It may sound somewhat strange or ridiculous- that
colours make our life colourful. Just think about a life and surroundings
without colour- it really is unimaginable. I read somewhere that dogs (and a
few animals as well) see the world in black and white. So a life without
colours is literally a Dog’s life. But what ‘colour’ really is- let us try to
understand.
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1.0
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When we try to describe any object (living or
otherwise), one of the most important features (may be along with shape and
size) which define the world around us is the colour of the object. But many
of us do not know how an object assumes one colour, or a combination of them
and another which does not. Here is an attempt to explain the same in simple
language.
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2.0
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We ‘see’ colours. That is understood. But what is
“seeing”? We can see things in light and cannot see in total darkness (except
dreams and fantasies may be). In scientific parlance, when light falls on any
object, the same gets reflected, mostly in a scattered manner. When such
reflected light falls on our eyes, the sensation it conveys to our brain,
creates a sensation which we call seeing.
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3.0
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So we have seen that light is basic external item
needed for colour. The light we have on earth comes from a single source only,
namely SUN. For most of the time, it comes directly from sun. Or light would
come from man-made mechanism which uses stored energy from sun again.
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4.0
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We all know that the light we get from sun is white in
colour. Courtesy the natural phenomenon of “rainbow”, we know that the white
light is combination of seven basic colours (called primary colours). We all
remember the VIBGYOR- Violet, Indigo, Blue, Green, Yellow, Orange and Red. So
white colour is a mixture of all seven colours and black is absence of all
colours. But how it is decided that an object will be of green or red colour
or pink or crimson. Wait a little and we will see.
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5.0
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To have an answer we will go back to point 2.0, where we
talked about seeing and bring a little complexity in the sentence that “… the
same gets reflected…” The truth is that when light falls on the object, it
partially reflected and partially absorbed. For the time being let us assume
that the source of light is white. The
basic funda of ‘colour’ of a body comes from a property of that body, which
of the seven component(s) or a combination of the same, will be absorbed and which
component(s) will be reflected.
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For example, when we ‘see’ an object of red colour, it
essentially means that the body has absorbed all the six other colours and
reflected (rejected??). If it reflects / rejects any other colour or a
combination, it will be defined as having those colours. Don’t we find it’s
ironical that an object’s colour is
known by the very things it rejects and not those absorbed.
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So, a white flower under a bright sun absorbs nothing.
It will however look blue in the bedroom with blue night lamp. A gloriously
red flower will however look black,
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