Earth’s inside • Crust. • Thin outer layer 8- 40 km thick. Made of Solid rocks and minerals floating on liquid mantle. • Mantle. • A sea of molten rocks and minerals called Magma 2,900 km thick. • Outer core. • Ring of liquid iron 2,500kmthick. • Inner core. • Solid iron 1,300km thick. The spinning iron cores turn the earth into a giant magnet.
Tectonic plates The crust isn’t solid It’s made of several Pieces called plates. There are 7 big plates & Several small ones.
Lithosphere • The mantle has convection currents in it. It moves like water. • The plates floats on this moving mantle. • Spreading • Where the mantle bubbles up a ridge is formed . • It pushes the crust apart as it solidifies and new crust is made. This is called spreading. • Subduction • Where two plates bump into each other, one gets sucked back down into the mantle and remelts. • These regions have lots of earth quakes and volcanos and mountains
Ring of fire The red line shows where Two plates are colliding This area has lots of earthquakes and active volcanoes
Types of Rocks • Igneous (made from fire) • These rocks are made when magma cools Extrusive igneous cools in the air or water quickly. It has small crystals No layers It can have air bubbles or be glassy Eg. Basalt, obsidian, pumice, scoria Intrusive igneous cools underground slowly. It has large crystals. No layers Eg. Granite Montreal is an intrusive volcano.
Types of rocks • Sedimentary (Rocks made by sedimentation) • These rocks are made when other rocks are broken by water, ice,roots, and acid. This is called Weathering. • The sand and gravel are carried away by wind, rivers, and glaciers. This is called Erosion. • It is then dropped in the bottom of lakes and oceans. Sedimentation.
Sedimentary rock as layers • Fossils • You can see grains of sand or gravel • No Crystals • Eg. Sandstone, limestone
Types of Rocks • Metamorphic (changed ) • Rocks that are heated and squeezed. This makes them melt and recrystalize • These rocks have narrow bands. Dark and light • Thin Layers • Small crystals • Eg. Schist, slate
transformations Rock that changes Metamorphic rock Gneiss Slate Marble Quartzite • Granite (igneous) • Shale (sedimentary) • Limestone (sedimentary) • Sandstone (sedimentary)