5The Layers of Planet Earth The CrustThe outer layer of Earth, made up of the features we see (mountains, valleys, hills, plains, etc.)This layer is bout km thick (the thinnest of all the layers)The MantleThe upper mantle is solid like the crustThe lower mantle melted rock that flows slowly (very hot here)This layer is 2900 km thick and makes up 67% of the Earth’s massThe crust and the upper mantle (solid layers) form the lithosphere
6The Layers of Planet Earth The Outer CoreThis layer is so hot that rock is completely liquefied (molten)This layer is about 2200 km thickThe Inner CoreThis layer is solid even though it is VERY hot (7000°C)The massive pressure from the other layers press the inner core into a hard ball of metalsThis layer is about 1250 km thick
7The Earth changes all the time, sometimes very quickly and sometimes very slowly Sudden ChangesEarthquakesVolcanoesTsunamisHurricanesTornadosLong-Term ChangesErosionWindWaterIceWeathering
8Earthquakes What is an earthquake? How does an earthquake happen? What are some of the side effects of an earthquake?
9How Earthquakes WorkThe first place where the rocks below the surface break is called the focus, and occurs along fault linesThe energy released by this sudden break is called spreads as waves called seismic wavesThe point on the surface of the Earth directly above the focus is called the epicentreGeologists use a seismogram to locate the epicentre and provide aid to those injured
11No. of earthquakes per year The Richter ScaleRichter scale no.No. of earthquakes per yearTypical effects of this magnitude< 3.4Detected only by seismometers30 000Just about noticeable indoors4 800Most people notice them, windows rattle.1400Everyone notices them, dishes may break, open doors swing.500Slight damage to buildings, plaster cracks, bricks fall.100Much damage to buildings: chimneys fall, houses move on foundations.15Serious damage: bridges twist, walls fracture, buildings may collapse.4Great damage, most buildings collapse.> 8.0One every 5 to 10 yearsTotal damage, surface waves seen, objects thrown in the air.
12VolcanoesA volcano is an opening in the Earth’s crust that allows solid and molten rock to escapeVolcanoes are easier to predict than earthquakesMagma - molten rock within the EarthLava - molten rock that flows out of a volcanoAsh - small, burnt particles from a volcanic eruption
13Gradual Changes to the Earth WeatheringThe process of breaking down rocks by water, wind, or iceErosionoccurs when the pieces of rock broken down from weathering move from place to place
143 Types of Weathering Mechanical Chemical Biological Rocks are broken apart by forces, like wind or waterChemicalRocks are broken apart by chemicals, like acid rain or air pollutionBiologicalRocks are broken apart by living things, like tree roots or animal/human use
15The Power of Moving Water As rivers flow they carry sand, gravel, mud these are called sedimentsAs these sediments sit on the bottom of lakes, rivers, oceans they become hard rocks this is called sedimentation
16Fast vs. SlowGlaciers slowly grow and shrink, scraping the Earth’s crust as they moveLandslide