Question

A coin in a glass beaker appears to rise as the beaker is slowly filled with water, why?

Answer 1

Do you know about refraction of light ? Yes, the bending of light when it passes obliquely from one medium to another medium is known as refraction of light.

Here in case of coin, Refraction of light is responsible for the apparent shift in position of the coin under water. Due to this reason coin in a glass beaker appears to rise as the beaker is slowly filled with water.

A rough diagram is shown in figure. See the apparent shift in position of the coin placed in water

Answer 2

Sarika collects things like marbles, coins, erasers etc. She takes some water in a glass and marks the level of water as 'O'.