Question

Liquids generally have lower density as compared to solids. But you must have observed that ice floats on water.Why?

Answer 1

the ice floats on the water because the density of ice is less than that of the water.this is the reason.
  ice=0.05
  water=1

Answer 2

this is due to the anamoulos expansion of water.
when water is cooled it contacts upto 4 degree celsius and then expands, this causes decrease in density. now the density  of ice is lesser than the density of water as it has expanded.so it is obvoius that it floats