A technician studies the behaviour of metal when it is melted and shaped again.
(i) Explain why the volume of metal remains the same when a solid object is completely melted and then cast into another solid shape, provided no material is lost during the process.
(ii) A block of solid iron is melted to obtain exactly 600cm3 of molten iron. This molten iron is poured into a cuboidal mould and all of it solidifies inside the mould. Without doing any numerical calculation, state whether the mass of the cuboid obtained will be equal to, greater than or less than the mass of the original block. Give a reason for your answer.