Solution - Class 9 PDF Download

Water has different two different densities as liquid water and as frozen solid water ie ice.

In ice the hydrogen bonding in water forms a crystalline lattice structure. This structure spaces the water molecules further apart compared to water molecules in liquid water.

Thus the volume of water increases, for the same weight(mass) of water. At 4 degrees Celsius water has the maximum volume.

Since density = mass/volume., the density of ice is less than liquid water.

That is why ice floats on water. Liquid water has a density of 1 g/cc, whereas density of solid ice is 0.91 g/cc. (about 0.1g/cc less. Water has its least density at 4 degree celsius.

That's why ice cubes float on juice and icebergs float on ocean water. Incidentally icebergs float with only one ninth visible outside the sea water. The remaining is submerged.

Note water molecules further apart in ice, compared to liquid water.

Floating iceberg on sea water.

Floating ice cubes on drinking water