CONDUCTION...

is the process by which heat or electricity is directly transmitted through a substance when there is a difference of temperature or of electrical potential between adjoining regions,without movement of a material.

                         EXPANSION...

is an action of becoming larger or more       extensive.

                        CONTRACTION...

is the process of becoming smaller.

   LAW OF CONVERSTAION OF ENERGY...

a fundamental concepts of physics,states that the total amount of energy remains constant in an   isolated system.

                 POTENTIAL ENERGY...

the energy possessed by a body by virtue of its position related to others,stressed within itself,electric charge, and other factors.

                     HEAT ENERGY...

is a form of energy which tramsfers among particles in a asubstance (or system).

                   KINETIC ENERGY...

is and energy that a body possessed by a virtue of being in motion.

                        CONVECTION...

the movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat.