Land, Water, and Air 2.2

Lithosphere Earth’s solid surface and interior Includes the crust, mantle, and core The crust and top layer of mantle are divided into huge, irregular-shaped slabs of rock called plates

Plate Tectonics Scientists believe Earth’s surface cracked into plates millions of years ago These plates have been moving and shifting This theory is known as plate tectonics

Continental Drift Plate tectonics is a theory that helps explain continental drift Continental drift is a theory of how continents move over time Today, Earth has 12 major plates and hundreds of smaller ones

Plate Movement Mountains form when plates bump into each other and push upward Earthquakes occur when two plates slide past each other, catch and create tension Eventually the tension is released and the ground shakes

Plate Movement (cont.) Volcanoes form along the edges of plates Hot rock from inside the earth oozes or explodes then flows onto surrounding land/ocean floor Plate movement has also created the Earth’s continents

Hydrosphere Earth’s liquid layer where water is found Includes all the water on Earth: Oceans Ponds Lakes Streams Groundwater Water in the air that forms clouds

Water Covers about 70% of Earth’s surface Necessary for life Humans are 50-75% water Helps chemical reactions take place (allows organisms to grow, digest food, and sweat)

Water (cont.) Helps the Earth remain at temperatures that can support life (water absorbs and releases heat) Earth is the only planet that has water in liquid form Other planets have ice or water vapor

Atmosphere Layer of air that surrounds Earth Contains a mixture of gases; nitrogen and oxygen Made up of four layers

Layers of Earth’s Atmosphere Troposphere 0-16km above Earth layer where people live and breathe; also where weather happens Stratosphere (16-50km above Earth) Mesosphere (50-80km above Earth) Thermosphere (80-480km above Earth)

Atmosphere Layers The farther a layer is from the Earth’s surface, the colder and thinner the air is Act as protective blankets of air Allows some of the sun’s rays to reach the Earth Keeps warmth in at nighttime

Ozone and UV The ozone layer is located in the stratosphere It absorbs most of the harmful ultraviolet radiation produced by the sun Ultraviolet radiation is a part of sunlight Small amounts help your skin make vitamin D Vitamin D helps your skin, eyesight, bone and tooth growth Too much can burn you, cause skin damage, cancer

Assignment Science in your Life Consumer Choices: Choosing Sun Protecting Pg. 53 #1-3 Turn in

Vocabulary Plate Tectonics Continental Drift Ozone Layer Lithosphere Atmosphere Hydrosphere Biosphere