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saltwater moraine rocks humus erosion metamorphic rock freshwater constructive processes landforms rock cycle lithosphere lava fault sedimentary rock minerals soil sediment topsoil Oceans dune Earth’s Materialsdeposition delta magma earthquake Earth’s layers continents volcano mantle igneous rock weathering glaciers crust inner core atmosphere outer core destructive processes Earth’s Water • 3/4 of Earth’s surface is covered by water • 97% of Earth’s water is found in its salty oceans and seas Earth’s water cont. • Liquid freshwater is contained in lakes, rivers, and wetlands. • Freshwater - water that is not salty Freshwater • About three-fourths (3/4) of Earth’s freshwater is stored as ice. This includes polar ice caps, glaciers, and snow. • Rainwater seeps into the soil. The water makes its way deep under the ground. It collects in layers of rock called aquifers. Discussion Question • Why is freshwater considered to be such an important resource? Earth’s Land • Earth is made up of several layers. Each layer is denser than the the layer above it. • The outermost layer of Earth is the crust. Earth’s Layers crust - Earth’s thinnest layer and the layer on which we live Crust • There are two types of crust: continental crust and oceanic crust. Continents are seven very large areas of land that make up our crust Landforms • Landforms - surface features • Mountains, hills, valleys, canyons, and plains Mantle • Earth’s thickest layer Core • The innermost layer is the core. It is made up of two parts. The outer core is liquid, and the inner core is solid. Earth’s Layers • Lithosphere - solid rocky material made of the Earth’s crust and the upper part of the mantle Crust • The crust, Earth’s outermost layer, makes up part of the lithosphere. • Litho means “rock.” • Earth’s crust is made up of rocks. Minerals • Mineral - a solid, nonliving material found in the ground • Earth contains about 4,000 different natural minerals. • Each mineral has its own properties. • Property - quality, such as color or hardness Minerals in Your Home • Table salt is a mineral called halite. • Your refrigerator is made of steel, which contains mineral iron. • Wires in your home are most likely made of copper. • Glass is made mostly of silica, a mineral found in sand. Rocks • Rock - a solid, nonliving material made up of one or more minerals • Each kind of rock is made up of certain minerals. Granite Pumice Limestone Some Kinds of Rock and Their Uses Rock How It Is Used Granite For buildings, countertops, statues, and tombstones As a building stone and to make concert Limestone Marble As a building stone and for statues, floors, and bathroom tiles Pumice In toothpastes, scouring cleansers, and polishing materials Slate For roofs, chalkboards, and walkways Chalk For writing and drawing, and in toothpaste Igneous Rock • Igneous rock - a rock that starts as melted rock deep inside Earth • Magma - melted rock • Sometimes magma reaches Earth’s surface, such as through a volcano. • On the surface, the melted rock is called lava. • When magma or lava cools, it becomes solid and forms igneous rock. Igneous Rock Granite forms from magma. Basalt is an igneous rock that forms from lava. Sedimentary Rock • Sedimentary rock is a rock that is formed in flat layers over a long period of time. • Sediment is loose pieces of rock, such as sand or pebbles. • Some sediment settles in layers on the bottom of rivers, lakes, and oceans. As the layers build up, pressure builds up too. The pressure squeezes the layers together. After a very long time, the sediment sticks together and forms sedimentary rock. Sedimentary Rock Sandstone forms from grains of sand and has a coarse texture. Shale forms from clay and mud and has a fine texture. Metamorphic Rock • Sometimes surface rock is pushed deep inside Earth. There, heat and pressure cause chemical changes in rock. Minerals in the rock combine in new ways. • Metamorphic rock is a rock that is formed by heat and pressure deep inside Earth. Metamorphic Rock • Both igneous and sedimentary rock can be changed into metamorphic rock. • Metamorphic rock itself can be changed into a different kind of metamorphic rock. The Rock Cycle • Earth’s rock is always changing. It is forming and breaking down. On Earth’s surface, wind, water, and gravity change rock. Inside Earth, heat and pressure cause changes. • Each of the three types of rock can turn into one of the other types. All the types of rock can also melt and become magma. • All the changes of rock from one type to another are called the rock cycle. The Rock Cycle Song • http://studyjams.scholastic.com/ studyjams/jams/science/rocksminerals-landforms/rock-cycle.htm Soil • The top part of Earth’s land is covered by soil. • Sediment is the main ingredient in soil. • Soil also holds water and air. • The water contains minerals that come from the sediment. • It also contains the remains of dead plants and animals. Soil • Over time, the remains break down into small bits. They make up a darkcolored material called humus. • Soil forms in different layers. The top layer is called topsoil. • Most plants grow in this layer. Discussion Questions • Which two kinds of rocks can form on Earth’s surface? • Which two kinds can form deep inside Earth?