Question

Which medium (the glass, water or diamond), is the most dense and how do you know?

Answer 1

\[d=\frac{m}{v}\]

You can measure the mass and volume of each object and determine which is more dense using the formula.

For your exact question, density from highest to lowest would be:
diamond
glass
water

Answer 2

diamond has higher value of refractive index than glass and glass has more refractive index than that of water because of diamond has more dense structure than glass due to one carbon atom attaches to other four carbon in tetrahedral manner but glass has less dense geometrical structure than diamond and more dense than water. in water due to hydrogen bonding its structure is less dense than glass and dimond due to more cavity in this geometrical structure.........