Original: A ship will float even though it may be made of steel ( which is much denser than water ) , because it encloses a volume of air ( which is much less dense than water ) , and the resulting shape has an average density less than that of the water .
Simplified: A ship floats because although it is made of steel which is more dense than water , it encloses a volume of air and the resulting shape has an average density less than that of the water .