Download Land, Water, and Air

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:
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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
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Science in your Life
Consumer Choices: Choosing Sun Protecting
Pg. 53
#1-3
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Vocabulary
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Plate Tectonics
Continental Drift
Ozone Layer
Lithosphere
Atmosphere
Hydrosphere
Biosphere