Learn Science through Sports – Jr.4
One of the wonders of nature is the ability of a body to float in water. The science or principle behind this ability of floatation is called 'buoyancy'. Once a body is immersed in water, 'buoyancy' is the force that acts to push it upwards.
Of course, not all objects can float. It depends upon the density and the weight of the object as well. That's why a football might float in water while a cricket ball might sink! Take a look at this video which explains what happens during swimming..