Answer the following questions :
Study the following procedure and answer the questions below:
(i)Take 3 spheres of iron , copper and lead of equal mass.
(ii) Put all the 3 spheres in boiling water in a beaker for some time .
(iii) Take 3 spheres out of the water . Put them immediately on a thick slab of wax.
(iv) Note the depth that each sphere goes into the wax.
Which property of a substance can be studied with this procedure ?