What is it called when rocks change from one form to another?

Rocks change from one form to another in a cycle called the rock cycle. The methods a rock changes forms is through heat and pressure, melting and cooling, weathering and erosion, and compacting and cementing.

Heat changes the rock's form by shifting the atoms in rock in it's solid state. Rocks are pulled underneath the earth's surface and the immense heat changes the rock's fundamental appearance. Pressure from tons of overlying rock combine with heat to morph rocks into different. The rocks created by pressure and heating are usually called metamorphic rocks.

Melting occurs at extremely high temperatures, where the rock is changed into its liquid state, a substance called magma or molten rock. When the molten rock leaves the extreme temperatures and cools, it changes back into a solid rock .These rocks are referred to as igneous rocks. The shapes of the newly formed rock depend on the rate at which it cools. If the rock cools fast, it is usually smooth, and if it cools slowly, it will most likely be coarse-grained.

Weathering and erosion is a long process where the rocks on the surface of earth are worn down by wind, rain, and other elements. This process leads to sediments that are transported easily by water and wind.

Compacting and Cementing is the process of the sediments being pressed together to form sedimentary rock. Water passing through the cracks in the sediments help 'cement' them even more.