The Earth as a System
The Earth is a system of 4 interacting components. Consists of:
- Geosphere - Hydrosphere- Atmosphere - Biosphere
The GeosphereComposition
• The solid part of the Earth (rocks, minerals, soil, etc.)– Most of the geosphere is below the surface
Thickness What is it?
Lithosphere 15-300km Cool, rigid layer that includes the crust; divided into plates
Asthenosphere 250km Plastic layer of the mantle that flows slowly, allowing plates above it to move
Outer Core 2200km Liquid nickel and iron
Inner Core 1228km Solid nickel and iron
The GeospherePlate Tectonics
• Look at the world map. Does anything look like it could fit together like a puzzle?
Pangaea – Wegener’s idea that all of Earth’s continents were joined into one giant landmass 200 million years ago.
The GeospherePlate Tectonics
• The tectonic plates ride atop the asthenosphere, moving in different directions
Boundary Movement Result
Convergent 2 plates move together
Mountains, volcanoes, earthquakes
Divergent 2 plates move apart
Ocean ridges (volcanic), rift valleys, earthquakes
Transform 2 plates slide past each other
Faults, earthquakes
The GeospherePlate Tectonics
Global Earthquake Distribution Global Volcano Distribution
The GeosphereEarthquakes Volcanic Eruptions
How does it happen?
Earth’s crust slips along a fault (crack in the crust)
Local Effects
Destruction, injuries, death
Global Effects
Tsunamis
Which of these geologic hazards poses the greatest threat to the environment? Why?
The GeosphereEarthquakes Volcanic Eruptions
How does it happen?
Earth’s crust slips along a fault (crack in
the crust)
Pressure of magma inside the volcano becomes so great that it blows open the solid surface.
Local Effects
Destruction, injuries, death
Destruction, injuries, death, mudflows,
improved soil fertility
Global Effects
Tsunamis Ash clouds from major eruptions can
block sunlight & change drop the
average global temp.
The GeosphereErosion
• Rocks on the surface are changed by wind, running water, and weather.
• Erosion is the removal and transport of weathered surface materials.
• Over long periods of time, erosion can wear away entire mountains and produce spectacular landforms.
The Atmosphere
• The atmosphere is a mixture if gases surrounding Earth
• Composition: Air Pressure: air pressure as altitude
The Layers of the AtmosphereThermosphere – high temps but molecules spread out, ions
Mesosphere – coldest layer, disintegrates meteors
Stratosphere – ozone layer (absorbs UV rays)
Troposphere – densest layer, weather occurs here
Energy in the Atmosphere• Radiation – transfer of energy in waves (ex:
sunlight)• Conduction – flow of heat from objects that are
touching• Convection – hot fluids rise and cool fluids sink
Greenhouse Effect• Greenhouse Effect - atmospheric gases
(greenhouse gases) trap heat near the Earth.
• Without the Greenhouse Effect the Earth would be too cold for life to exist!
The HydrosphereIncludes all of the water on or near the Earth’s surface (oceans, lakes, rivers, polar icecaps, groundwater, & clouds)
The Water Cycle is the continuous movement of water into the air, onto the land, and then
back to water sources.
- Evaporation – the change of state from a liquid to a gas (liquid water to water vapor)– Condensation – the change of
state from a gas to a liquid (water vapor to liquid water)
– Precipitation – any form of water that falls to Earth’s surface from clouds (rain, snow, etc.)
– Runoff – excess water that flows off of the surface
The HydrosphereThe Water Cycle
Think-Pair- Share
How are all of Earth’s spheres (geosphere, atmosphere, hydrosphere, and biosphere) connected by the water cycle?
The HydrosphereEarth’s Oceans
All of Earth’s oceans (Atlantic, Pacific, Indian,& Arctic Oceans) are connected. Oceans cover over 70% of Earth’s surface.
The HydrosphereOcean Currents
Surface Currents Caused by wind patterns Influence climates of land
areas they flow pastEx: The Gulf Stream (warm
surface current) makes the British Isles warmer than other areas at the same latitude)
Deep CurrentsCaused when cold, dense
polar water sinks below warmer, less dense water and flows toward the equator
Surface Ocean Currents
Common surface ocean currents show the flow of
the sea
In 1993, thousands of rubber duckies washed up on Alaskan
beaches. Oceanographers determined that a ship carrying the toys lost a container during a storm near Hawaii in 1992. The ducks were used to map
ocean currents.
Oceans: The Global Temperature Regulator
The main function of the world ocean is to:Absorb & store energy
from the sun How?Water absorbs and
releases heat slower than land does.
**Without the ocean, the temperature of Earth’s atmosphere would be too extreme for life
Fresh WaterOnly 3% of Earth’s water is
freshMost freshwater is held in
polar icecaps and glaciersLess than 1% of all Earth’s
water is groundwaterRain and melted snow sinks into
the ground forming groundwater. A rock layer called an Aquifer stores and allows the flow of groundwater.
Groundwater gives people drinking water and supplies water for many agricultural & industrial needs
The biosphere is the narrow layer of Earth where life can exist.
• Life on Earth requires:A. Liquid water
B. Temperatures between 10°C and 40°C
C. Source of energy
a. Plants & algae use sunlight to make food
b. Most other organisms get energy from what they eat
Earth is a closed system – energy is transferred among living things through the food chain.
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