Question: Why does metal sink but boats float?

Leila Nichol answered on 22 Mar 2013:

A ship is a vessel filled with air basically, this gives it buoyancy. But if it’s not watertight, water will enter and sink it, same as when a ship maybe hits an iceberg like titanic and sinks. A piece of metal will sink but a metal cup, upright, filled with air, won’t sink!