With the use of Archimedes' Principle, state how you will find relative density of a solid denser than water and insoluble in it. How will you modify your experiment if the solid is soluble in water?

Explanation

(i) Using a spring balance, the weight of the solid in air is measured = `W_1`
(ii) The solid is now completely immersed in a beaker filled of water such that it does not touch the walls and bottom of beaker. With the same spring balance the weight is again measured. Weight of the solid fully immersed in water = `W_2`
So, loss in weight of solid when immersed in water = `(W_1-W_2)`.
Now, relative density = Weight of solid in air/ Loss of weight of solid in water
So, relative density = `W_1//(W_1-W_2)`.
If the solid is soluble in water, then instead of water, other liquid is to be taken in which the solid is insoluble and sinks in that.
Now, relative density = (Weight of solid in air/Loss of weight of solid in liquid ) x R.D. of the liquid.