How can a boat made of styrofoam float?

The size of the boat is equal to the water displaced by the boat. This means, if the boat is bigger then its weight, the boat will float. If the boat is smaller than its weight, it sinks. This is why...

it floats by the shape of the hull but it needs to be balanced evenly other wise it will topple over and sink

Bla Bla bla Yes and No

Boats are made out of many different materials; the only requirement is that they be waterproof (since boats are used in the water). Historically, boats were always made of wood since there wasn't...

The outside of the boat is metal, but the inside is mostly air. So the weight of the boat of a certain volume (size) is smaller then the weight of water of an equal volume (size). Because of this,...