Why does a ship float on water but the needle sink?

A ship floats on water but the needle sink because of the Buoyancy.

Archimedes’s law states that a body immersed in water displaces its volume of water, and if this displaced volume of water weighs more than the body immersed, the body will float. If it weighs less than the body, the body will sink.

So, the volume of water displaced by the needle weighs less than the needle, and it sinks.

In simple terms, the nail sinks because the density of the steel/needle is greater than the density of the water.

Whereas, a ship has a lot of hollow spaces(filled with air) because of which the overall density of the ship becomes less than water. 

Therefore the immersed portion of the ship displaces water equal to its weight, and it floats.


Simply Easy Learning

Updated on: 10-Oct-2022


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