1 Removing heat energy, or cooling, decreases the motion of molecules. 2  If heat is added to a solid, the molecules can move fast enough to change from a solid to a liquid. ( 3 Melting). 4  If heat is added to a liquid, the molecules can move fast enough to change from a liquid to a gas.
Fossils usually only form in sedimentary rock. Sediments have to accumulate over the organism in order to preserve it. This could be a rapid burial, such as a volcanic eruption or mudslide, it could be sap from a tree oozing over an insect, or simply a slow sediment accumulation on the bottom of a lake.
Sedimentary rocks are formed by the accumulation of sediments. There are three basic types of sedimentary rocks. Clastic sedimentary rocks such as breccia, conglomerate, sandstone, siltstone, and shale are formed from mechanical weathering debris. Chemical sedimentary rocks, such as rock salt, iron ore, chert, flint, some dolomites, and some limestones, form when dissolved materials precipitate from solution.