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If
we go deep in the phenomena related to the blue sky nature, we have
to study the interaction between light and particles of small
size, the so-called Rayleigh Dispersion.
Normally,
when any electromagnetic wave (such as sunlight) finds in its trajectory
an atom (or a small molecule), it interacts with its cloud of electrons,
transmitting energy to the atom. This causes that the atom lowest
level of energy (the natural state) begins to vibrate.
The
oscillating electrons do not keep on vibrating for a long time.
They return to the initial state by irradiating some of the energy
they have got. Lord Rayleigh studied the dependence between the
amount of irradiated light and the light wave length. He set up
that the quantity of irradiated light is inversely proportional
to the fourth power of the wave length. It can be represented as:
Therefore,
if the incident light is white (an addition of different wave lengths
or colours), the irradiated light will contain a higher amount of
colours with shorter wave length (blue and violet) and less amount
of colours with longer wave length (yellow and red). So we came out
to the same conclusion than in the previous section. |
