Method of heat transfer

Answer 1

Convection: when two material touch, Conduction: in a fluid (this involves a bulk flow rate of the fluid and the calculations are usually ignored in basic high school physics), and Radiation: in jaja.

Answer 2

Heat is transferred by three different mechanism: Conduction, Convection, and Radiation

• In conduction, the molecules/atoms of a warmer substance bang up against the molecules of a cooler substance and transfer some of their energy to the cooler material until the two come into thermal equilibrium (the same temperature). Obviously they have to be in contact for this to occur
• In convection a mass/blob/chunk of warmer material moves into a region of cooler material and when it mixes with it, the average energy of the new region is higher - heat has been transferred. Note that since the material has to move for this to happen we normally just see convective heat transfer in fluids (gases, liquids, supercritical fluids, and plasma).
• In radiation it's a little more complex. As long as the temperature of a body is greater than absolute zero, inter-atomic/inter-molecular collisions will cause the kinetic energy of the colliding atoms or molecules to change. This results in charge-acceleration and/or dipole oscillation which produces electromagnetic radiation even at a single temperature. This electromagnetic radiation can move even though a vacuum - which is why the Sun can heat the earth and you can feel heat coming off a fire even when the surrounding air is still quite cold. Materials at higher temperatures give off more thermal radiation (actually electromagnetic radiation due collisions) than the same material at lower temperatures, so a hot object that ca "see" a cold object will send more energy to the cold object than the cold object sends back towards the hot object - resulting in a net increase of energy in the cold object - heat has been transferred.

Answer 3

Heat can be transferred through conduction (direct contact), convection (through fluid movement), and radiation (via electromagnetic waves). Each method has unique characteristics and is dependent on the nature of the materials involved.