Refraction disk

Specifications

A metallic circular disk graduated (0-90º) in 4 quadrants and subdivided into 1º.
A transparent acrylic semi-circular tank is fitted on the metallic disk to find out the refractive index of different liquids as for example water, oil, etc.
All this assembly is fitted on a metallic base which is graduated from 1-7 to place the light box at any desired level.