Heat also flows in all directions unless channeled controlled or directed. The rate of heat transfer depends on the physical caracteristics of the heating equipment used, the medium used to transfer heat, and the temperature difference between the source of the heat and the substance to which the heat is imparted. Heat is transferred by conduction when the heat source is in direct contact with the object to be heated. For example, a pan placed on a hot stove changes temperature rapidly by conduction. The pan is in direct contact with the hot stove and the better the contact with the stove the faster the temperature conducts into the pan.
Conduction occurs in liquids, solids and gases.
Heat is transferred by convection when the warmer and cooler molecules of liquid or gas mix with one another. For example, heat generated by a strip heater causes molecules in the air around the heater to move faster, in turn causing the air to expand. Because the heated air contains fewer molecules than coolerr air per given volume, the heated air is lighter and therefore rises. Simular to your fireplace chemmey. As it rises it mixes with cooler air.