Glass of water contains ice cubes . What would happen to water level if the ice cubes melts ?

 We know that ice is less denser than water . That's why ice floats on water .

As density is inversely proportional to volume , volume of ice is more compared to volume of water . So the volume of water what we get when ice melts  , is comparatively lesser to that of water which was present in the glass earlier .

As the ice melts , it will change into denser liquid water and this water occupy lesser space as compared to the space it was occupying when it was ice .

Thus we can say that water level decreases when the ice melts .