Rocks: Mineral Mixtures 8th Grade
Section 1:Understanding Rock • What exactly is rock? • A solid mixture of crystals of one or more minerals, that range in all sizes from pebbles to formations that are thousands of kilometers long.
The Value of Rock • Rock is an important natural resource. • Used by early humans to make tools such as hammers, spears, knives, and scrapers. • Used for centuries to make buildings, roads, and monuments. • Certain types of rocks have helped build ancient and modern civilizations. • Rock study has helped scientists to discover the history of life on Earth.
Fossils • Help provide information of life forms that lived thousands of years ago.
The Rock Cycle • Rocks in the Earth’s crust are constantly changing shape and composition. • The way the rock forms determines the type of rock that it is. • The three main types of rocks are: igneous, sedimentary, and metamorphic.