APPLICATIONS
1. Animals have soft skeletons (unlike those of terrestrial) : The density of animals and fish living in water is almost same as the density of water. Therefore their weight is almost completely balanced by buoyancy. That is why they do not need massive skeletons like those of terrestrial animals.
2. Aquatic plants have soft stems : The density of water plants is almost the same as the density of water. Therefore, its weight is almost completely balanced by buoyancy or up thrust.
3. A fish posses an organ called swimming bladder, which is compressible i.e. it can change its density to move up or down in the water.
4. Submarine can travel under water.
5. It is easier to swim in sea water than in river water.
6. A balloon filled with helium gas rises in air and it rises to a particular height only.
7. A ship made up of iron does not sink in water, while an iron nail sinks in it.
8. A body weighs more in vacuum than in air
9. It is difficult to drown in the dead sea water.
10. Birds flap their wings in order to fly.
11. Huge masses of ice (ice berg) are seen to float in water.
Density of ice (di) = 900 kg/m3, density of water (dw) = 1000 kg/m3. Thus the density of ice is less than the density of water. Hence 9/10 th part of the ice is immersed in the water and only 1/10 th part is seen out side the water.