What is HEAT?

Heat is a form of energy. When something is heated, it's molecules gain kinetic energy and so they move around more rapidly. The molecules knock off each other, moving further apart which generally makes the substance expand.

HEAT IS MEASURED IN JOULES(J) OR KILOJOULES(kJ).

What is HEAT TRANSFER?

Heat moves from an area of high temperature to an area of low temperature, until both areas are of the same temperature.
For example, if you pour warm water over ice cubes, heat moves from the the water to the ice. The ice will melt and the water will be cooler than before. What has happened is that the water lost heat and the ice gained heat until both mixed and were of the same temperature.

HEAT CAN BE TRANSFERED IN THREE WAYS: CONDUCTION, CONVECTION AND RADIATION. :)