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4th Grade Earth Science Chapter 9 Changing of Earth’s Surface What is the Earth made of? • Landforms on Earth include: – – – – – Mountains __________ __________ - flat land Plateaus ________ Gorges - a deep crack Plains - flatlands with few trees ______ valleys - on land where mountains are close _______ together – ______ Ridges - beneath the ocean, long row of towering mountains – ________ Trenches - long narrow canyons in the ocean floor Earth’s Features • Earth’s surface is made up of many different __________. Landforms • Earth’s surface is constantly ________ and so changing are the landforms weathering • ___________ - the process of breaking down rock into smaller pieces • Forces of __________ include ________ and weathering water _____ ice Mechanical / Chemical Weathering • _________________ - process of breaking Mechanical Weathering down rock into smaller pieces as a result of ice or water – MINERALS THAT MAKE UP THE ROCK DO NOT CHANGE! • ________________ - minerals that make up Chemical Weathering the rock change. • The cause of chemical weathering is a _________ with something in the reaction water or ________ oxygen environment such as ____ Erosion erosion • ________ - the process by which soil and sediments are transferred from one location to another • The movement of soil and sediments can be caused by: – _________ wind – ________ water – ______ ice – ________ gravity Water • _________ - solid particles that are moved from sediments one place to another deposition __________ - sediments that form during weathering and erosion are deposited in another location During the process of deposition, the _______ and shape direction of a river’s flow changes ________ As rivers flow to the oceans they carry ________ sediments Dissolved minerals which are useful to plants and ______________ and animals to carry out their __________ Life processes Soil Erosion • Areas of land with no plant covering are Soil erosion susceptible to __________ • __________ - help prevent soil erosion by Plant roots holding the soil in place Cover crops • ___________ - planted by farmers in between harvests to prevent soil erosion and add nutrients to the soil • ______________ Dust Bowl of 1930’s - years of drought and poor farming practices left bare areas of soil Soil soil - made of weathered rock, air, water, and • ____ the remains of living things. weathering • __________ - process of breaking down rocks through physical factors such as _____, frost drought rainwater or__________________. Changes in temperature _________, _______ • ________ = non-living parts of the soil inorganic • As rock breaks down small pieces collect on the surface Volcanoes • __________ occur when magma from the Volcanoes mantle either flows or explodes through the crust. – Opening in the surface of the Earth through which magma rises – Occur near ______________ Plate boundaries – Theory of plate tectonics – one plate sinks beneath another at a plate boundary – sinking crust melts into _______. magma lava - Magma that reaches the surface – _____ Draw and Label Volcanoe page 270271 Earthquakes Earthquakes are caused by the sudden shifting • _________ of rock as tectonic plates shift positions – Pressure builds up, rocks lurch forward, and the Earth’s crust shakes. – ______ focus - the underground point where the earthquake occurs epicenter - point on the Earth’s surface directly – ________ above the focus. Waves • Energy from the earthquake is carried by _______. waves focus and • Waves spread out from the _____ ________. Volcanoes • Waves can cause the Earth to move ________, Up and down ___________, or in a ___________ Back and forth Circular motion • As the waves spread out from the epicenter, they __________. Lose energy Earthquakes and Plate boundaries California Alaska • ____________ and _________ have had the most earthquakes because they are located on Plate Boundary between the Pacific plate and a ____________ the North American Plate. • The strength of an earthquake can be measured on a ____________ Magnitude scale - a series of numbers that is based on the amount of energy that is released.
