Thermal energy - JSS2 Basic science Past Questions and Answers - page 2

The three main mechanisms of heat flow are conduction, convection, and radiation. Conduction involves the transfer of heat through direct contact between particles. Convection occurs through the movement of fluids (liquids or gases). Radiation involves the transfer of heat through electromagnetic waves.

Heat flow refers to the transfer of thermal energy between two objects or systems due to a temperature difference, while temperature is a measure of the average kinetic energy of particles in a substance. Heat flow occurs until thermal equilibrium is reached, where the temperatures of the objects are equalized.

The direction of heat flow is determined by the temperature difference between two objects or systems. Heat always flows from objects or systems with higher temperatures to those with lower temperatures until thermal equilibrium is achieved.

An example of conduction is when you touch a metal spoon in hot soup and feel it getting warm. Convection is demonstrated when you boil water in a pot, and the hot water rises while cooler water sinks, creating a circulation pattern. Radiation is evident when you feel the warmth of sunlight on your skin without any physical contact.