Rocks
Review Rock Cycle – the transitions of rock through the three main rock types (sedimentary, igneous, metamorphic) Sedimentary – rock type formed from layers of rocks, shells, or other materials Metamorphic – rock that has been changed into new rock by heat or pressure Igneous – rock formed from melted rock that has cooled
Jellybean Video (copy and paste link): https://youtu.be/pm6cCg_Do6k
Sedimentary Rocks Wind and water break down the earth Sandstone Limestone Conglomerate Sedimentary Rocks Gypsum Shale Wind and water break down the earth Bits of earth settle in lakes and rivers Layers are formed and build up Pressure and time turn the layers to rock
Metamorphic Rocks Gneiss Schist Rocks that have changed They were once igneous or sedimentary Pressure and heat changed the rocks
Igneous Rocks Fire Rocks Formed underground by trapped, cooled magma Scoria Granite Pumice Obsidian Fire Rocks Formed underground by trapped, cooled magma Formed above ground when volcanoes erupt and magma cools
Fossils – remains, or traces of past life preserved in rock Weathering – breaking down of rocks to form sediment Hardness – resistance to being scratched Luster – how a surface reflects light Two types: metallic and nonmetallic (glassy, pearly, dull, greasy, etc.)
Rock/Mineral Properties Color Odor Texture Crystallization/Shape Weight
How do rocks form? How much time does it take to form a rock? If you squeeze and heat a rock for a few million years, it can turn into a new kind of rock.
Where does the heat come from? When rocks are close enough to the magma to be heated but not close enough to be melted, the rocks can be changed.
Where does the pressure come from? Rocks below the surface are squeezed by the layers above them Thicker layers = more pressure
What makes up the earth?
What is the difference between rocks and minerals? A mineral is a nonliving solid found in nature. But, aren’t rocks nonliving and found in nature too?? Then what is the difference between a rock and a mineral?
Rocks and Minerals Rocks are made up of one or more minerals!!! The reason why some rocks have more than one color, is because they contain more than one mineral. Also, some rocks are made of other things, such as sand and pebbles, in addition to minerals. Geologists use many different property tests to help them to identify rocks/minerals!
How do we know the strength of rocks and minerals? The Mohs Hardness Scale was designed for us to use as a scale to determine the strength of rocks and minerals.
Other “mineral tests” Streak Test – what color does the rock/mineral leave on a streak plate? Luster Test – how does the rock/mineral reflect light? Acid Test – how does the rock/mineral react with an acid?