Rocks contain important evidence about the origin of the earth. Geologists classify rocks into three basic types based upon the processes by which the rocks are formed. The first type is igneous rock, which is formed from magma. If magma reaches the earth’s surface, it changes into the lava that spills from volcanoes.
Carbon dating is used to determine the age of biological artifacts up to 50,000 years old. This technique is widely used on recent artifacts, but educators and students alike should note that this technique will not work on older fossils (like those of the dinosaurs alleged to be millions of years old). This technique is not restricted to bones; it can also be used on cloth, wood and plant fibers.