Polarimeters are used for determining the amount of polarization of light in optically active substances. Ordinary light from the sun or a lamp is composed of disorderly waves that vibrate in all directions perpendicular to the light beam. But optically active substances polarize light in such a way that the light beam consists of orderly waves that vibrate in only one direction. Polarimeter laboratory instruments measure the optical rotation of optically active substances. The angle of polarization - rotation can be quite unique per substance. UV Visible spectrophotometers and polarimeters are widely used in testing pharmaceuticals, chemicals, food additives, perfumes, and sugars.