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.
All three rock types - igneous, sedimentary, and metamorphic - make up a portion of the rock cycle. Igneous rocks are rocks that formed directly from magma and can form either in the earth or on its surface. Igneous rocks can weather and be compressed to form sedimentary rocks, rock made up eroded material broken off of other rocks and cemented together, and both of these can be transformed into metamorphic rock.