A student has two solid blocks that have different masses. The student knows that each block is composed of a pure substance, but she wants to know if the blocks are composed of the same pure substance. Which of these would best show that the blocks are composed of different substances?
A.
Both blocks sink when placed in water.
B.
Both blocks can be scratched by a piece of glass.
C.
One block conducts electricity and the other does not.
D.
One block has a greater volume than the other block.