A Polariscope is an instrument that is used to investigate the distribution of stress within transparent materials such as glass, polymers, and crystals. It is based on the theory of birefringence, which is a property in which a material has unique refractive values along different planes due to its internal pressure. When polarized light passes through such materials, it splits into two beams, each being unique because it bounces in a different direction. The relationship between each of these beams shows important information about the stress condition of the material.