This experiment explores the way light is scattered by particles and shows the effect of polarization. By focusing the light to a photo detector, we can measure the polarization angle of scattered light accurately. The scattering of light by suspended molecules in water produces linearly polarized light in the plane perpendicular to the incident light. As shown in the figure, if the charges in a molecule are oscillating along the y-axis, it will not radiate along the same axis. Therefore, at 90° from the beam direction, the scattered light is linearly polarized.

This apparatus to understand the helps students principles and applications of polarization and investigate the applications of polarizing materials. The polarized light interacting with materials produces a number of optical effects. Some effects involve chiral (asymmetric) molecules that twist the polarization axis of some of the incoming light. Other effects involve the alignment of large polymer molecules. Still others involve materials with different indices of refraction depending on the polarization of the incoming light. Polarized light can be used to see or detect where there is stress in some kind of plastics. The strain viewer setup illustrates an important industrial method used to examine photo elastic stress. Light and its interactions with matter form the main focus for this activity.

The experimental arrangement consist of a continuous source, slit, collimating lens and a high index dispersive prism. The light from a bright point source is collimated by a lens and is allowed to pass through a high index dispersive prism. The spectrum of the light can be observed through the prism
Once the spectrum is obtained a glass box containing optically active solution arranged between two polaroids is inserted in to the light path. As polaroid is rotated, a dark band moves through the spectrum. This is due to the absorption of the colour/wavelength by the polaroid which corresponds to the rotated angle.

Birefringence or double refraction, is the decomposition of a ray of light into two rays (the ordinary ray and the extraordinary ray) when it passes through certain types of material depending on the polarization of the light. This effect can occur only if the structure of the material is anisotropic.
If the material has a single axis of anisotropy or optical axis, (i.e. it is uniaxial) birefringence can be formalised by assigning two different refractive indices to the material for different polarizations. The birefringence magnitude is then defined by

Any material that literally rotates the polarization direction of light moving through it is said to be optically active. Some active materials change the state of polarization from linear to circular or perpendicular to linear and back again through birefingence. Most plastics like cellophane and plastic wrap are optically active, as are sugars (and solutions of sugars) and various minerals including ice and mica. Usually the amount of activity depends on the wavelength of the radiation as well as the thickness and orientation of the material.