Rocks
Categories Igneous Sedimentary Metamorphic Petrifaction
How do you think rocks form?
Sedimentary Rocks Formed when layers of sediment are pressed together. Pressure and heat cement the layers into solid rocks.
Igneous Rocks Formed when molten or liquid matter from inside Earth comes to the surface, cools, and hardens.
Metamorphic Rocks Formed when heat and pressure over long periods of time work to fuse together other kinds of rock.
Petrified Rock Rock formed when plant or animal remains are replaced with minerals and chemicals.