Sinking and Floating: Buoyancy

Why does a small clump of steel sink, while a 50,000-ton steel ship can float?

In order to remain afloat, a ship needs to displace an amount of fluid equal to its own weight. Therefore, if a clump of steel is placed in water, it will sink because it is much denser than water and its volume isn’t large enough to displace a weight of water equal to its own weight. A 50,000-ton steel ship can easily stay afloat because it can displace 50,000 tons of water. That is because its hull isn’t all steel, but contains a large amount of air. Therefore its density, its mass divided by its volume, is less than that of water.


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