Melting is the process of being changed from a solid to a liquid state especially by the application of heat. This occurs when the energy of the solid increases, which increases the substance's temperature to the melting point. Typically, the solids energy increases by the application of heat or pressure. At the melting point, the ordering of molecules in the solid breaks down to a less ordered state, and the solid "melts" to become a liquid.
Energy can be extracted from water by gravitational force as done in hydroelectric plants, temperature gradients that creates natural convection processes, the mechanical variations of ocean currents and surface waves, and by nuclear fussion.
