A copper rod has one end put into hot water. Thermal energy is conducted along the rod, causing the opposite end to become warmer. Which atomic-level behaviour of the copper explains most of the movement of thermal energy from one end to the other?
- AAtoms at the hot end gain kinetic energy and move towards the other end.
- BAtoms at the hot end expand, colliding with other atoms and transferring energy.
- CFree electrons at the hot end gain energy and move towards the other end, colliding with atoms along the rod.
- DFree electrons at the hot end gain energy from the hot water and move directly to the other end.