Overview

The transfer of Thermal Energy as heat requires a difference in temperature between 2 points of transfer.

Heat may be transferred by means of Conduction, Convection or Radiation.

Conduction is the transfer of thermal energy due to collisions between the molecules in the objects. Collisions between atoms and molecules trasnfer kinetic energy from the warmer to the cooler object. The object must be in Physical contact.

Convection is the thermal energy transferred by the flow of matter.

Radiation is the transfer of energy by electromagnetic radiation. Radiation can be travelled in a vacuum.






List the three ways of heat transfer and explain how it processes in the above diagram.

Conduction. The heat produced from the fire heats up the base of the pot. As the base warms up, the atoms and molecules at the base of the pot will starts to vibrate violently, and will then collide with the neighbouring atoms, causing them to vibrate as well. Thus, heat will then slowly transfer to the cooler region of the pot. However, the handle of the pot is an insulator of heat, thus heat cannot be transferred easily, hence insulators of heat are good materials to protect our hands from burns or scalding.

Convection. The fire from its source will slowly heat up the water in the pot. As the water heats up, water will expands. The density of water will then decrease and it will rise, due to the inbalance of density in water. The cool water will then sinks and as it sinks, it will get heats up again, causing it to rise. Thus a convection cycle will then goes on in the water.

Radiation. The heat produced from the fire source is give out to the surroundings. Heat is transfer to the surroundings by infra waves.