Consider the following two situations, in which case the volume of sponge will be more?
Situation 1: Sponge on a table
Situation 2: Sponge wet by water
Volume of sponge will be same in both conditions.
Sponge is porous. It have holes in it which is filled with air. When the holes are filled with water it shrinks as water occupies lesser space than air as it have stronger molecular forces of attraction. But the volume of sponge will remain constant, only density of sponge will change.