Which of the following properties remains constant when a metal rod is heated?
When metal is heated, it expands because it has more energy. Therefore, we can eliminate C and A. If we have the same amount of metal, but that metal has a larger volume, it would follow that the rod would be less dense, so B is gone. The only one left is D. mass. If the heating is done properly, the metal should gain nothing but energy, keeping its mass the same.
