1 Answers
1. Heat passes through solids by conduction only.
2. When one end of a rod is heated, the molecules near the hot end receive the thermal energy and start oscillating with larger amplitudes.
3. In doing so, they collide with the neighbouring molecules and transfer a part of their energy to these molecules.
4. The molecules which receive the energy vibrate with increased amplitudes and collide with the neighbouring molecules. Thus, energy of thermal motion is transferred by molecular collisions down the rod.
5. As the distance of a molecule from the hot end increases, its amplitude of oscillation decreases and hence there is continuous decrease in temperature.
6. This transfer of heat continues till two ends of the object are at the same temperature.
7. In metals, mainly free electrons conduct the heat energy.