Urine Refractometer 3 level controls

Specific gravity is usually determined using a commercial refractometer or urine dipstick. The principle used in relation to the refractometer is to measure the refractive index. Refractive index is a comparison of the speed of light in air with the speed of light in solution (urine). The rate depends on the concentration of dissolved particles in the solution, which in turn affects the angle of light passing through the solution.