This model helps students to study the refraction and reflection of light when it travels from one medium into another. This model comes with a rotating base, making it possible to change the angle of incidence and the angle of refraction. It providesa high degree of accuracy when making measurements as well as an easy way to change angles without disturbing light source or the object the light is being shown upon. This refraction and reflection demonstration model Includes an acrylic semi-circle that can be filled with different mediums for measuring the index of refraction. A light source is mounted on the base with single, double, triple and wide slit attachments, two metal shields for blocking light, an acrylic lens for focusing the beam of the light. Light rays change direction when it passes one medium into another medium. In other words, the ray bents. The bending is caused by the differences in density between the two substances. By adding different types of liquids to the refraction tank and shining a light bundle on the flat side of the tank, you will see that the light refracts once it travels through the medium in the tank. This is caused by the fact that the density of light (where the light bundle travels through before it hits the refraction tank) is different than the density of the medium. The refraction tank displays the angle of refraction – this is the anglethat the refracted ray makes with the normal line (the line that isperpendicular to the line where the two mediums meet at a right angle) – and the angle of incidencein steps of 1°. By changing the medium in the refraction tank, you will see that the light bundle will have a different angle of refraction for each medium. Students can compare the different mediums, and advanced students can determine what medium is in the refraction tank by measuring the index of refraction for that medium. The model comes with teacher’s instructions to make optimum use of the model. A power supply is required (not included).