Even after a glass is filled to the brim with water you can add a considerable amount of salt without making the water run over how is this possible?

Answer 1

since water is a liquid, there is still space in between the water molecules. So if you pour salt slowly into the a glass full of water, the salt molecules will occupy the empty spaces between the water molecules, until it reaches a point called sturation point when there isn't any space left and then the glass will overflow. But this will only work if you stir the water to help the mixing of the two substances. Interesting addendum: the water will actually shrink for the first few grains of salt as the electrostatic nature of the ionic salt will pull the water molecules closer together.

Answer 2

Its not possible according to the law of conservation of mass that the water level will go down.. There must be a hole in the container.. Check carefully