Chapter 3 Power Point Notes The Dynamic Earth

1. Chapter 3 Power Point NotesThe Dynamic Earth

2. Section 1 Notes

3. Our Planet The Earth as a System • Geosphere: The solid part of the Earth that consist of all rock, as well as the soil and loose rocks on Earth’s surface. • Atmosphere: The mixture of gases that make Up the air we breathe. • Tectonic Plate: A block of lithosphere that consists of the crust and the rigid, upper part of the mantle. As they collide they form mountains. EX:*The Himalayan Mountains are still being formed from colliding plates. *Largest plates: Pacific, Antarctic, and Eurasian. **Earth is considered to be an integrated system (made up of parts that work well together)

4. Earth’s Interior • Scientist use seismic waves to learn about Earth’s interior. • Seismic waves: are the waves that travel through Earth’s interior during an earthquake. Composition of the Earth The Earth is divided into 3 layers (based on chemical composition): • Crust: Earth’s thin outer layer. It is composed of almost entirely of light elements. 20 km to 70 km thick • Mantle: The layer beneath the crust. It makes up 64 % of the mass of the Earth. Approximately 2,900 km thick • Core: Earth’s innermost layer. Is composed of the densest elements. Has a radius of approximately 3,400 km

5. Structure of the Earth • The Earth can be broken down into 5 layers - based on its physical properties. • Lithosphere (outer layer): cool, rigid layer; 15km to 300km thick; includes the crust and uppermost part of the mantle; “tectonic plates” • Asthenosphere: the layer beneath the lithosphere. Is a plastic, solid layer; made of rock that flows very slowly; allows plates to move above it; 250 km thick • Mesosphere: Below the asthenosphere; lower part of the mantle; 2550 km thick • Outer Core: Dense liquid layer; 2200 km thick; made of liquid nickel and iron • Inner Core: Solid, dense core made up mostly of iron and nickel; temperature ranges: 4,000 C to 5, 000 C

6. Earthquakes • Fault: A break in the Earth’s crust in which blocks of the crust slide relative to one another. • Earthquake: When rocks that are under stress suddenly break along a fault, a series of ground vibrations is set off. These vibrations cause slippage along the fault. • Occur all the time – but are so small we cannot feel them. • Richter scale: used by scientists to quantify the amount of energy released by an earthquake; smallest 2.0 largest 9.5 ; Each increase by 1 whole # indicates the release of 31.7 times more energy

7. Earthquake Hazard • Scientist CANNOTpredict when earthquakes will occur. • Information where they are MOST LIKELY to occur can help people prepare. • An earthquake-hazard area is determined by past and present seismic activity. • States with the highest risk: West Coast states , New Madrid earthquake zone, and the area around Charleston, SC

8. Volcano • A mountain built from magma (melted rock) – that rises from the Earth’s interior to its surface. • Often located near tectonic plate boundaries where plates are either colliding or separating from one another. • May occur on land or under the sea (to eventually become an island). • Majority of active volcanoes are located along tectonic plate boundaries that surround the Pacific Ocean.

9. Volcanoes Local Effects of Volcanic Eruptions: Global Effects of Volcanic Eruptions: Can be devastating to local economies Can cause great human loss Clouds of hot ash, dust, and gases can flow as speeds of up to 200 km/hr (mixed with water – can cause mudslides) Can change Earth’s climate for several years Clouds of volcanic ash and sulfur-rich gases may reach the upper atmosphere They reduce the amount of sunlight that reaches the Earth

10. Erosion: the removal and transport of surface material. Water Erosion Wind Erosion Erosion by both rivers and oceans can produce dramatic changes to the surface. Rain can also cause water erosion. Can blow soil away. Beaches and deserts have loose, sandy soil that is vulnerable to wind Soft rocks (sandstone) erode more quickly than do hard rocks( granite)

11. Section 2 Notes

12. The Atmosphere: A mixture of gases that surrounds the Earth. Composition of the Atmosphere: • Nitrogen: 78 % • Enters the atmosphere when volcanoes erupt and when dead plants and animals decay • Oxygen: 21 % • Is primarily produced by plants • Other Gases: argon, carbon dioxide, (CO2), methane (CH4) (most abundant greenhouse gas) and water vapor • CO2: produced from animals

13. Layers of the Atmosphere Troposphere Stratosphere Layer nearest the Earth Extends to about 18 km above Earth’s surface Almost all weather occurs in this layer Earth’s densest atmospheric layer Temp and pressure as altitude Above the troposphere Extends about from 18 km to about 50 km Temperature as altitude Ozone in this layer absorbs sun’s UV rays Ozone: O3 (3 O atoms)

14. Layers of the Atmosphere Cont’d Mesosphere Thermosphere Layer above the stratosphere Extends to an altitude of about 80 km The coldest layer (temps have been measured as low as -93° C) Layer farthest from Earth’s surface Nitrogen and oxygen absorb solar radiation (raises temps to above 2000° C) This would not feel hot (not enough particles at this level to transfer heat) In the lower thermosphere some N and O atoms become electrically charged (become ions) This level is also called the ionosphere. These ions give of lights at time (Northern lights)

15. Energy in the Atmosphere • Radiation: the transfer of energy across space and in the atmosphere ex. When you stand in front of a fire • Conduction: the flow of heat from a warmer object to a colder object ex. Place a metal pan on the stove top • Convection: the transfer of heat by currents ex. Holding your hand above a pot of boiling water and feel the warmth.

16. Heating and Moving of Air in the Atmosphere • Radiation: moves energy through space in waves – to heat the Earth’s surface. • Near the Earth’s surface, air is heated by conduction. • Convection currents: are caused by the unequal heating of the atmosphere. Warm air rises and cool air sinks.

17. The Greenhouse Effect • Sunlight that penetrates the Earth’s atmosphere heats the surface of the Earth. • Earth’s surface radiates heat back to the atmosphere (some escapes into space) • The remainder of the heat is absorbed by greenhouse gases(gases in our atmosphere that trap and radiate heat)– which warms the air. • Keeps the Earth from being too cold for life to exist.

18. Section 3

19. The Hydrosphere and Water Cycle • Water cycle: the continuous movement of water into the air, onto land, and then back to water sources. • Evaporation: the process by which liquid water is heated by the sun and then rises into the atmosphere as water vapor. • Condensation: water vapor forms water droplets on dust particles, which form clouds. They eventually stick together and form heavier droplets. • Precipitation: the heavier droplets fall from the clouds as rain (sleet , hail, or snow)

20. Earth’s Oceans • Atlantic Ocean, Pacific Ocean, Arctic Ocean, and Indian Ocean, and join together to make the world ocean. • The world ocean covers 70 % of the Earth’s surface!!! • Largest Ocean: Pacific Ocean (1.66 x 108 km2) ; • 2nd largest: Atlantic Ocean (8.16 x 107 km2) • Smallest Ocean: Arctic Ocean (1.44 x 106 km2)

21. Earth’s Oceans Cont’dSalinity and temperature – 2 main properties Ocean Water Temperature Zones Contains more salts than fresh water Mostly sodium chloride (NaCl) Salinity: the concentration of all the dissolved salts Average salinity: 3.5% Surface zone: is warmed by the sun These waters are stirred by waves and currents Deep zones have temperature slightly above freezing (never get sunlight)

22. Ocean Currents Surface Currents: • Are streamlike movements that occur at or near the surface of the ocean. • Are wind driven and result from global wind patterns. • May be warm-water or cold-water currents. • Phytoplankton: tiny, free-floating marine algae that is driven by the current. Deep Currents: • Are streamlike movements of water that flow very slowly along the ocean floor. • Forms when cold, dense water From the poles sinks below warmer, less dense ocean water.

23. Fresh Water V’S Groundwater • Water found in lakes, rivers, wetlands, the soil, and rock layers below the surface. • A little over 3% of all water on Earth is fresh water. • Most of this is trapped in icecaps and glaciers. • Mississippi River cover about 40% of the contiguous US. • A network of streams that drains an area of land is called a river system. • Water that sinks into the ground collects there or runs off. • Is what is used by humans for fresh drinking water and water supplies for agricultural/industrial needs. • Accounts for less than 1% of all water on Earth • Aquifer: a rock layer that stores water. • All precipitation either becomes runoff or groundwater.

24. The Biosphere • The narrow layer around Earth’s surface in which life can exist. • Made up of the uppermost part of the geosphere, most of the hydrosphere, and the lower part of the atmosphere. • Extends about 12 km into the ocean and about 9 km into the atmosphere. • Gravity allows a planet to maintain an atmosphere and to cycle materials. Life on Earth Suitable combinations of materials and energy organisms need to survive are found in the biosphere. Requires: liquid water, moderate temperatures,a source of energy These materials must be continually cycled

25. Energy Flow in the Biosphere Closed System • Energy enters and leaves the system, but matter does not. • Earth is a closed system because no matter leaves. • Energy: enters Heat: leaves Open System • Both matter and energy are exchanged. • Earth was once an open system. • Matter entered when comets and meteorites hit the Earth (now very little matter reaches the Earth)