Question

Give reason as to why an iron needle sinks in water but a ship made of iron floats in water.

Answer 1

The iron ship is constructed in such a way that it is mostly hollow from within Hence the average density of the ship is less than that of water (i.e. less than 1 $g/c{m}^3$ ) wheres iron needle being compact and its density is 7.6$g/c{m}^3$ which is more than 1 $g/c{m}^3$ (density of water) Hence the needle sinks in water.