Abbe refractometer (The use and how it works)
https://www.youtube.com/watch?v=CW9gOyH8HIA&t=157s
Refractometer Basics
https://www.youtube.com/watch?v=lij4oawWONg
REFRACTIVE INDEX DEPENDS ON THESE FACTORS
The refractivity index is affected by three different major factors: the frequency of light, the temperature and the concentration of the liquid.The final factor affecting refractive index is concentration. In general the more concentrated a compound is the higher the refractive index will be. Frequently the concentration of a solution
(sugar in water) can be plotted versus the refractive index and used to calculation the
concentrations of other samples (of sugared water).