Chapter 3 Power Point Notes

Chapter 3 Power Point NotesThe Dynamic Earth

1Section 1 Notes

22Our PlanetThe Earth as a SystemGeosphere: The solid part of the Earth that consist of all rock, as well as the soil and loose rocks on Earths surface. Atmosphere: The mixture of gases that makeUp 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 formmountains. EX:*The Himalayan Mountains are stillbeing 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)

33Earths InteriorScientist use seismic waves to learn about Earths interior.Seismic waves: are the waves that travel through Earths interior during an earthquake.

Composition of the EarthThe Earth is divided into 3 layers (based on chemical composition):Crust: Earths thin outer layer. It is composed of almost entirely of light elements. 20 km to 70 km thickMantle: The layer beneath the crust. It makes up 64 % of the mass of the Earth. Approximately 2,900 km thickCore: Earths innermost layer. Is composed of the densest elements. Has a radius of approximately 3,400 km

4Structure of the EarthThe 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 platesAsthenosphere: 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 thickMesosphere: Below the asthenosphere; lower part of the mantle; 2550 km thickOuter Core: Dense liquid layer; 2200 km thick; made of liquid nickel and ironInner Core: Solid, dense core made up mostly of iron and nickel; temperature ranges: 4,000 C to 5, 000 C

5EarthquakesFault: A break in the Earths 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

6Earthquake HazardScientist CANNOT predict 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

7VolcanoA mountain built from magma (melted rock) that rises from the Earths 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.

8VolcanoesLocal Effects of Volcanic Eruptions:Global Effects of Volcanic Eruptions:Can be devastating to local economies Can cause great human lossClouds of hot ash, dust, and gases can flow as speeds of up to 200 km/hr (mixed with water can cause mudslides)

Can change Earths climate for several yearsClouds of volcanic ash and sulfur-rich gases may reach the upper atmosphereThey reduce the amount of sunlight that reaches the Earth

9Erosion: the removal and transport of surface material.Water ErosionWind ErosionErosion 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)

10Section 2 Notes

11The 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 decayOxygen: 21 %Is primarily produced by plantsOther Gases: argon, carbon dioxide, (CO2), methane (CH4) (most abundant greenhouse gas) and water vaporCO2: produced from animals

12Layers of the AtmosphereTroposphereStratosphereLayer nearest the EarthExtends to about 18 km above Earths surfaceAlmost all weather occurs in this layerEarths densest atmospheric layerTemp and pressure as altitude

Above the troposphere Extends about from 18 km to about 50 kmTemperature as altitude Ozone in this layer absorbs suns UV raysOzone: O3 (3 O atoms)

13Layers of the Atmosphere ContdMesosphereThermosphereLayer above the stratosphereExtends to an altitude of about 80 kmThe coldest layer (temps have been measured as low as -93 C)

Layer farthest from Earths surfaceNitrogen 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)

14Energy in the AtmosphereRadiation: the transfer of energy across space and in the atmosphere ex. When you stand in front of a fireConduction: 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.

15Heating and Moving of Air in the AtmosphereRadiation: moves energy through space in waves to heat the Earths surface.

Near the Earths surface, air is heated by conduction.

Convection currents: are caused by the unequal heating of the atmosphere. Warm air rises and cool air sinks.

16The Greenhouse EffectSunlight that penetrates the Earths atmosphere heats the surface of the Earth.Earths 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.

17Section 3

18The Hydrosphere and Water CycleWater 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)

19Earths OceansAtlantic Ocean, Pacific Ocean, Arctic Ocean, and Indian Ocean, and join together to make the world ocean.The world ocean covers 70 % of the Earths 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)

20Earths Oceans ContdSalinity and temperature 2 main properties Ocean WaterTemperature ZonesContains more salts than fresh waterMostly sodium chloride (NaCl)Salinity: the concentration of all the dissolved saltsAverage salinity: 3.5%

Surface zone: is warmed by the sunThese waters are stirred by waves and currentsDeep zones have temperature slightly above freezing (never get sunlight)

2121Ocean CurrentsSurface 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.

22Fresh Water VS 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 EarthAquifer: a rock layer that stores water.All precipitation either becomes runoff or groundwater.

23The BiosphereThe narrow layer around Earths 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 EarthSuitable combinations of materials and energy organisms need to survive are found in the biosphere.Requires: liquid water, moderate temperatures,a source of energyThese materials must be continually cycled

24Energy Flow in the BiosphereClosed SystemEnergy enters and leaves the system, but matter does not.Earth is a closed system because no matter leaves.Energy: enters Heat: leaves

Open SystemBoth 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)

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