You must have often seen a dead body floating in water, in movies. Why does a dead body float on water? According to the Archimedes’ principle, when a body is partly or fully immersed in water, it displaces water equal to its volume. A body floats on water when its weight is less than the displaced volume of water. If its weight is the same as that of the displaced volume of water, it will remain fairly steady at whatever depth it might be. Usually, the bodies whose density is less than that of water, float. For example, wood and cork float on water because their densities are less than that of water. Going by the same principle, bodies whose density is more than that of water, sink. The density of the human body is less than that of the water. Therefore, when a man falls into the water, he floats for a few seconds in it. But, when water goes into his body, his density becomes more than the water and he drowns. When his body starts expanding due to this water, the volume of the body increases and thus the density decreases. In other words, the weight of the water displaced by his body becomes more than that of the body. And as a result, it starts floating.
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