The Polarization of Light
As a wave passes through a polarizer, depending on the orientation of the polarizer, it is
supposed that only that part of the wave that is plane parallel to the polarizer passes through it.
If light is polarized vertically it will be able to pass through a second vertical polarizer. If the
second polarizer as at a ninety degree angle to the first, no light will pass through it (upper part
of the figure).

It is still a mystery to physics, in spite of the standard explanations, why placing a polarizer at an
oblique angle between two polarizers at ninety degree angles allows some light to pass through
the final polarizer (lower part of the figure).
This figure shows the analogy of light to a taut spring being made to wave through a sectioned box.
This is believed to be strictly analogous to the wave part of particle/wave duality of light.
Source: Aethro-Kinematics
Source: Aethro-Kinematics
Polarization Explained in Terms of a Transverse Wave Theory of Light
The phenomenon of polarization specifies the directions of the electric and magnetic fields
associated with an electromagnetic wave. When an ordinary beam of light is emitted by an atom
or molecule, all directions of vibration are possible, thus the resultant beam of electromagnetic
radiation is a superposition of waves. The result is an unpolarized light wave.
The drawing on the left is an unpolarized
light beam viewed along the direction of
propagation (perpendicular to this page).
The time-varying electric field vector can
be in any direction in the plane of the
page with equal probability.

The drawing on the right is a linearly
polarized light beam with the time-varying
electric field vector in the vertical direction.
The Polarization of Light
The direction of polarization of the electromagnetic wave is defined to be the direction in which
the electric field vector is vibrating or oscillating. A wave is said to be linearly polarized if the
orientation of the electric field is the same for all individual waves at all times at a particular point.
Source: Principles of Physics: Third Edition p. 919
As described on the third Light page a revised wave theory of light explains this polarization of light
without assuming it to be modeled on the transverse wave of a taut string.
Alternate Explanation