Chapter 3Chapter 3

When you see this symbol, When you see this symbol,

copy the slide. We will just copy the slide. We will just discuss the other slides.discuss the other slides.

Do-Now-Copy AND answer the following questions on a separate sheet of paper.

1.How do you think you did on the ch. 1 Test?

2.How long did you study?

3.Did you fully complete the review sheet?

4.What could YOU do to improve your grade?

5.What could WE do to help you?

ObjectivesObjectives• Describe the composition and structure of

the Earth.• Describe the Earth’s tectonic plates.• Explain the main cause of earthquakes

and their effects.• Identify the relationship between volcanic

eruptions and climate change.• Describe how wind and water alter the

Earth’s surface.

StandardsStandards• SCSh7a

• SEV1a

• SEV1e

The Earth as a SystemThe Earth as a System• Earth is an integrated system made of rock, air,

water, & living things that all interact.• Four parts:

• Geosphere • solid, rocky part from core to crust

• Atmosphere • mixture of gases we breathe as air

• Hydrosphere • water on or near Earth’s surface

• Biosphere • Earth’s surface to 9km high, living things found here

Discovering Earth’s InteriorDiscovering Earth’s Interior• Use seismic waves

– The same waves that travel through Earth’s interior during an earthquake

– A similar process would be you tapping on a melon to see if it is ripe.

– A seismic wave is altered by the nature of the material through which it travels.

– Measure changes in the speed and direction of seismic waves that penetrate the interior of the planet.

• We have learned that the Earth is made up of different layers & have inferred what substances make up each layer.

The Composition & Structure of The Composition & Structure of EarthEarth

• Scientists have classified Earth’s composition and structure two different ways.– Chemical make up– Physical structure

The (Chemical) Composition of the The (Chemical) Composition of the EarthEarth

• 3 Layers of Earth:• Crust

• Thin, outermost layer, <1% of Earth’s mass

• Mantle• Rock between crust & core, 64% of Earth’s mass

• Core• Central part of Earth, made of densest elements

• These layers are made up of progressively denser material toward the center of the Earth.

**These layers are based on CHEMISTRY.

The (Physical) Structure of EarthThe (Physical) Structure of Earth• 5 Layers of Earth

– Lithosphere• Outermost layer, made of crust and upper mantle, divided into

tectonic plates– Asthenosphere

• made of mantle rock that slowly flows– Mesosphere

• “middle sphere,” lower mantle– Outer Core

• Outer shell of core, made of liquid nickel and iron– Inner Core

• Innermost, solid nickel and iron

**These layers are based on PHYSICAL PROPERTIES.

Plate TectonicsPlate Tectonics• Tectonic plates are blocks of lithosphere

made of the crust and the rigid, outermost part of the mantle & glide across the asthenosphere.

• Major tectonic plates – Pacific, North America,South America, Africa,

Eurasian, & Antarctic plates.

Plate BoundariesPlate Boundaries• Much geological activity occurs here

• Enormous forces are generated with these actions causing mountains to form, earthquakes to shake the crust, & volcanoes to erupt along the plate boundaries.

EarthquakesEarthquakes• A fault is a break in the Earth’s crust along which

blocks of the crust slide relative to one another.– When rocks that are under stress suddenly break

along a fault, a series of ground vibrations (earthquakes) is set off.

• Occurring all the time• The measure of the energy released by an

earthquake is called magnitude.– The smallest magnitude that can be felt is 2.0, and

the largest magnitude ever recorded is 9.5. Magnitudes greater than 7.0 cause widespread damage.

Where do Earthquakes Occur?Where do Earthquakes Occur?• At or near tectonic plate boundaries

because of the enormous stresses that are generated when tectonic plates separate, collide or slip past each other.– Over the past 15 million to 20 million years,

large numbers of earthquakes have occurred along the San Andreas fault in California, where parts of the North America plate and the Pacific plate are slipping past one another.

Earthquake HazardEarthquake Hazard• Can’t predict when earthquakes will take place• Information about where earthquakes are likely

to occur helps people prepare.• An area’s earthquake-hazard level is determined

by past and present seismic activity.• Earthquake-resistant buildings, built in high risk

areas, are slightly flexible so that they can sway with the ground motion preventing them from collapsing.

VolcanoesVolcanoes• Mountains built from magma, or melted rock,

that rises from the Earth’s interior to the surface, & can occur on land or in the sea.

• Often located near tectonic plate boundaries where they are colliding/separating– Most (active) are located along tectonic plate

boundaries that surround the Pacific Ocean (Ring of Fire).

Remember this?Remember this?

• Environmental problems are divided into three categories:– Local– Regional– Global

Local Effect of Volcanic EruptionsLocal Effect of Volcanic Eruptions• Clouds of host ash, dust, and gases can flow

down the slope of a volcano at speeds of up to 200 km/hr and sear everything in their path.

• During an eruption, volcanic ash can mix with water and produce mudflow that runs downhill.

• In addition, ash that falls to the ground can cause buildings to collapse under its weight, bury crops, damage the engines of vehicles, and cause breathing difficulties.

Global Effects of Volcanic Global Effects of Volcanic EruptionsEruptions

• Major volcanic eruptions can change Earth’s climate for several years.

• In large eruptions, clouds of volcanic ash and sulfur rich gases may reach the upper atmosphere, and spread across the planet reducing the amount of sunlight that reaches the Earth’s surface.

• The reduction in sunlight can cause a drop in the average global surface temperature.

ErosionErosion• Earth’s surface is continually battered by wind &

scoured by running water.• Is the process where Earth’s surface are

loosened, dissolved, or worn away & transported by a natural agent, like wind, water, ice or gravity.– Wears down rocks & makes them smoother as times

passes• Older mountains are therefore smoother than younger ones.

ObjectivesObjectives• Describe the composition of the Earth’s

atmosphere.

• Describe the layers of the Earth’s atmosphere.

• Explain three mechanisms of heat transfer in Earth’s atmosphere.

• Explain the greenhouse effect.

StandardsStandards

• SCSh7a

• SEV1e

• SEV3a

The AtmosphereThe Atmosphere• The atmosphere is a mixture of gases that

surrounds a planet.– Nitrogen, oxygen, carbon dioxide, and other gases

• Gases are added to & removed from the atmosphere. – For example:– Animals remove oxygen when they breathe in & add

carbon dioxide when they breath out.– Volcanic eruptions also add gases to the atmosphere,

while vehicles both add & remove gases.

• Insulates Earth’s surface

Composition of the AtmosphereComposition of the Atmosphere• Nitrogen makes up 78% of Earth’s atmosphere

– enters when volcanoes erupt & dead plants/animals decay

• Oxygen is the 2nd most abundant gas & is primarily produced by plants.

• Other gases such as argon, carbon dioxide, methane, & water vapor make up the rest.

• Many types of tiny, solid particles, or atmospheric dust

Air PressureAir Pressure• Earth’s atmosphere is pulled toward our

surface by gravity, so the atmosphere is denser near the Earth’s surface.

• Air becomes less dense with elevation, so breathing at higher elevations is more difficult.

Layers of the AtmosphereLayers of the Atmosphere• 4 layers based on temperature changes

that occur at different distances above the Earth’s surface:• The Troposphere• The Stratosphere• The Mesosphere• The Thermosphere

TroposhereTroposhere• Lowest layer

• Temperature drops at a constant rate as altitude increases

• Where weather conditions exist

• Densest atmospheric layer & extends to 18 km above Earth’s surface

StratosphereStratosphere• Lies immediately above the troposphere &

extends from about 10 to 50 km above the Earth’s surface

• Temperature rises as altitude increases because ozone in the stratosphere absorbs the sun’s ultraviolet (UV) energy & warms the air.

• Because ozone absorbs UV radiation, it reduces the amount of UV radiation that reaches the Earth. UV radiation that does reach Earth can damage living cells.

MesosphereMesosphere

• Above the stratosphere

• Extends to an altitude of about 80 km.

• Coldest layer of the atmosphere where temperatures have been measured as low as –93ºC.

ThermosphereThermosphere• Farthest from Earth’s surface • Nitrogen & oxygen absorb solar radiation resulting in

temperatures measuring above 2,000 ºC.• Air is so thin that air particles rarely collide, so little heat

is transferred, & wouldn’t feel hot to us• The absorption of X rays & gamma rays by N & O

causes atoms to become electrically charged (IONS).• The lower thermosphere is called the ionosphere.

– Ions can radiate energy as light, & these lights often glow in spectacular colors in the night skies near the Earth’s North & South Poles.

Energy Transfer in the AtmosphereEnergy Transfer in the Atmosphere• Radiation is the energy that is transferred

as electromagnetic waves, such as visible light & infrared waves.

• Conduction is the transfer of energy as heat through a material.

• Convection is the movement of matter due to differences in density that are caused by temperature variations an can result in the transfer of energy as heat.

Heating of the AtmosphereHeating of the Atmosphere• Solar energy reaches the Earth as

electromagnetic radiation– visible light, infrared radiation, & ultraviolet light

• About 1/2 the solar energy that enters the atmosphere passes through it and reaches the Earth’s surface, while the rest of the energy is absorbed or reflected in the atmosphere by clouds, gases, & dust or it is reflected by Earth’s surface.

• The Earth does not continue to get warmer because the oceans & the land radiate the absorbed energy back into the atmosphere.

The Movement of Energy in the The Movement of Energy in the AtmosphereAtmosphere

• As a current of air rises it cools, & eventually becomes more dense than the air around it & sinks. It then moves back toward the Earth until heated & less dense & then begins to rise again.

• The continual process of warm air rising & cool air sinking & moving air in a circular motion is called a convection current.

The Greenhouse EffectThe Greenhouse Effect• Warming of the surface & lower atmosphere of

Earth that occurs when carbon dioxide, water vapor, & other gases in the air absorb & reradiate infrared radiation

• The gases in the atmosphere that trap &

radiate heat are called greenhouse gases.• Most abundant greenhouse gases:

– water vapor, carbon dioxide, methane, and nitrous oxide

The quantities of carbon dioxide & methane in the atmosphere vary considerably as a result of natural &

industrial processes.

ObjectivesObjectives

• Name the three major processes in the water cycle.

• Describe the properties of ocean water.• Describe the two types of ocean currents.• Explain how the ocean regulates Earth’s

temperature.• Discuss the factors that confine life to the

biosphere.• Explain the difference between open and closed

systems.

StandardsStandards

• SCSh7a

• SEV1d

• SEV2b

• SEV2d

• SEV3a

The HydrosphereThe Hydrosphere

• Includes all of the water on or near Earth’s surface– oceans, lakes, rivers, wetlands, polar ice

caps, soil, rock layers beneath Earth’s surface, & clouds

The Water CycleThe Water Cycle• Continuous movement of water from the ocean to the

atmosphere to the land & back to the ocean• Water continually evaporates (liquid to a gas) from the

Earth’s oceans, lakes, streams, & soil.• Water vapor forms water droplets

(condensation=gas to liquid) on dust particles which then form clouds in which the droplets collide to create larger, heavier drops that then fall as precipitation (rain, snow, sleet, hail).

Earth’s OceansEarth’s Oceans• Play important roles in the regulation

of the planet’s environment & temperature.

Ocean WaterOcean Water• The difference between ocean water & fresh

water is that ocean water contains more salts.• Salinity is a measure of the amount of dissolved

salts in a given amount of liquid.– Lower in places that get a lot of rain or where fresh

water flows in to the sea– Higher where water evaporates rapidly & leaves the

salts behind– Most salt is sodium chloride– Many other elements present

Fresh Water and River SystemsFresh Water and River Systems• Fresh water is water that contains

insignificant amounts of salts.

• Most is in icecaps & glaciers

• Also in lakes, rivers, wetlands, the soil, & atmosphere

Remember The Biosphere?Remember The Biosphere?• The only part of Earth where life exists

• Extending about 11 km into the ocean & about 9 km into the atmosphere

• The biosphere is located near Earth’s surface because most of the sunlight is available near the surface.

• The materials that organisms require must be continually recycled. Gravity allows a planet to maintain an atmosphere & to cycle materials.

Energy Flow in the BiosphereEnergy Flow in the Biosphere• The energy used by organisms must be obtained in the

biosphere & must be constantly supplied for life to continue.

• When an organism dies, its body is broken down & the nutrients in it are used by other organisms (flow of energy).

• Closed systems=can’t exchange matter or energy with surroundings

• Open systems=can exchange both matter & energy with surroundings

• Earth is…– A closed system with respect to matter– An open system for energy as energy travels from plant to

animal which is eaten by other animals. Some energy is lost as heat to the environment.