Question

Take a glass vessel and pour some glycerine into it and then pour water up to the brim. Take a quartz glass rod. Keep it in the vessel. Observe the glass rod from the sides of the glass vessel.
What could be the reasons for these changes?

Answer 1

When this arrangement is viewed from side, the size of the glass rod appears increased in water($\mu =1.33$) and glass rod($\mu =1.5$) disappeared in glycerine($\mu =1.47$) because both the glass rod and glycerine have same refractive index. When mediums have same refractive index the speed of light is same in both the medium, so no bending or refraction takes place.

The size of glass rod appears increased in water due to taking place of refraction.