Chapter 3 The Dynamic Earth Section 1 The

Chapter 3: The Dynamic Earth

Section 1 The Geosphere

The Earth as a System • The Earth is an integrated system that consists of rock, air, water, and living things that all interact with each other. • System divided into four parts: • • The Geosphere (rock) The Atmosphere (air) The Hydrosphere (water) The Biosphere (living things)

The Earth as a System

The Composition of the Earth • Earth divided into three layers: 1. The crust 2. The mantle 3. The core • Material of each layer progressively gets denser as you move toward the center of the Earth

The Crust • Thin and solid outermost layer of the Earth • Makes up less than 1% of the planet’s mass • Divided into two types – Continental Crust (under land) • 20 km to 70 km thick beneath the continents • Up to 4 billion years old • Less dense – Oceanic Crust (under ocean) • 5 km to 8 km thick beneath the oceans • Younger (180 million years or less) than the continental crust • ** Dense!! **

Layers of the Earth

The Mantle • The mantle is the layer of rock between the Earth’s crust and core • Made of rocks of medium density • 64% of the mass of the Earth • Divided into two layers: – Upper Mantle • The crust + the top half of the upper mantle = the lithosphere – Solid, rigid layer 15 km to 300 km thick – Divided into huge pieces called tectonic plates • The lower portion is partially molten = the asthenosphere – Crustal plates carrying the continents move on this layer – Lower Mantle • Called the mesosphere

Output Page: Earth’s Layered Structure

The Core • The core is the central part and is composed of the densest elements (iron-nickel alloy) • about 1/3 of Earth’s mass • Divided into two types – Outer Core • dense liquid layer • Convective flow of metallic iron within generates Earth’s magnetic field – Inner Core • dense, solid inner core • Estimated to be between 4, 000°C to 5, 000°C but under enormous pressure

Earth’s Layers

Tectonic Plates

Plate Tectonics • Tectonic plates are blocks of lithosphere that consist of the crust and the rigid, outermost part of the mantle – glide across the underlying asthenosphere – Continents are located on the plates – A plate moves as a unit with respect to the surrounding plates – Explains most geologic processes • The major tectonic plates include: – Pacific, North American, South American, African, Eurasian, and Antarctic plates

Plate Boundaries • Much of the geological activity takes place at plate boundaries (where two tectonic plates meet) – plates may separate, collide, or slip past one another generating enormous forces – mountains form, earthquakes shake the crust, and volcanoes to erupt

Earthquakes • An earthquake is the vibration of Earth produced by the rapid release of energy – Resulting from two tectonic plates sliding past one another – Occur mostly at plate boundaries – Occurring all the time. Many are so small that we cannot feel them!

• Focus – the area along a fault at which slippage first occurs, initiating an earthquake. – The released energy radiates in all directions from the focus in the form of seismic waves

• Epicenter – the point on Earth’s surface directly above the focus of an earthquake Faults are fractures in Earth where movement has occurred

• The measure of the energy released by an earthquake is called magnitude

Where do Earthquakes Occur?

Discovering Earth’s Interior • Scientists use seismic waves to learn about Earth’s interior – Altered by the nature of the material through which it travels • Seismologists measure changes in the speed and direction of seismic waves that penetrate the interior of the planet – Conclusion: 1. ) Earth made up of different layers 2. ) inferred what substances make up each layer

Discovering Earth’s Interior

Volcanoes • A volcano is a mountain built from magma (melted rock) that rises from the Earth’s interior to the surface – Can occur on land or in the sea • often located at plate boundaries – The majority of the world’s active volcanoes surround the Pacific Ocean (The Ring of Fire)

Local Effect of Volcanic Eruptions • Clouds of hot ash, dust, and gases can flow down the slope of a volcano and sear everything in their path – ash can mix with water and produce a mudflow that runs downhill – ash can cause buildings to collapse, bury crops, damage vehicle engines, and cause breathing difficulties

Global Effects of Volcanic Eruptions • Major volcanic eruptions can change Earth’s climate for several years – clouds of ash and sulfur rich gases may reach the upper atmosphere, reducing the amount of sunlight that reaches the Earth’s surface – can cause a drop in the average global surface temperature

Output Page: Volcano Comic Strip • Turn your Interactive Notebook horizontal • Draw 6 squares on your page • Design, draw and color a comic strip. The storyline should deal with volcanoes! • Use the following vocabulary words in your story and underline them!! – Volcano, Ash, Lava, Destruction, Mud Flow, Eruption

Erosion • Erosion is the process in which the materials of the Earth’s surface are loosened, dissolved, or worn away and transported form one place to another by a natural agent, such as wind, water, ice or gravity – wears downs rocks and makes them smoother as times passes • older mountains are smoother than younger ones • Two main types: – Water Erosion – Wind Erosion

Water Erosion • Erosion by both rivers and oceans can produce dramatic changes on Earth’s surface – waves from ocean storms can erode coastlines rivers can carve deep gorges into the landscape (Grand Canyon)

Wind Erosion • Wind also changes the landscape of the planet – In places where few plants grow, such as beaches and deserts, wind can blow soil away very quickly – Soft rocks, such as sandstone, erode more easily than hard rocks, such as granite

Section 2 The Atmosphere

The Atmosphere • The atmosphere is a mixture of gases that surrounds a planet – Includes N, O, CO 2, etc. – Gases can be added and removed from living organisms, geologic processes, man-made influences • Plants/trees, volcanic eruptions, vehicles

• Also insulates Earth’s surface – Slows the rate at which the Earth’s surface loses heat and keeps Earth at a temperature which living things can survive

Major Components of the Atmosphere • A mixture of different gases and particles – Nitrogen largest component • Mainly entering atmosphere by volcanic eruptions – Oxygen is the 2 nd largest • Primarily produced by plants

Variable Components • Water vapor – Source of all clouds and precipitation – Absorbs heat given off by Earth – Also absorbs some solar energy • Ozone – Form of oxygen (O 3) – Filters most of the UV rays from the sun • No ozone = uninhabitable planet for most living organisms Too hot!! • Atmospheric dust – Tiny, solid particles

Air Pressure • Atmosphere pulled toward surface by gravity – denser near the Earth’s surface and thins as you travel away from Earth • Few gas molecules to detect • Experience weightlessness • Breathing at higher elevations difficult

Layers of the Atmosphere • The atmosphere is divided into four layers based on temperature 1. The Troposphere 2. The Stratosphere 3. The Mesosphere 4. Thermosphere

Output Page: Copy and Color the Layers of the Atmosphere

The Troposphere • Bottom layer of the atmosphere • Temperature decreases with an increase in altitude • Where weather conditions exist • Densest atmospheric layer and extends 18 km above Earth’s surface

The Stratosphere • Lies immediately above the troposphere • Extends 10 to 50 km above the Earth’s surface • Temperature rises as altitude increases • Ozone absorbs the sun’s ultraviolet (UV) energy and warms the air

The Mesosphere • Extends to an altitude of about 80 km. • Coldest layer of the atmosphere – as low as -93ºC.

The Thermosphere • Layer located the farthest from Earth’s surface • Nitrogen and oxygen absorb solar radiation (X rays/gamma rays) – temperatures above 2, 000 ºC – atoms become electrically charged producing ions

• the lower thermosphere is called the ionosphere • Ions radiate energy as light producing Aurora Borealis • Air is so thin that air particles rarely collide –little heat is transferred, therefore not feel hot

Output Page: Tattoo or Body Art • You are in charge of developing a tattoo to allow the world to know about Aurora Borealises • The centerpiece of the tattoo must be a slogan or phrase as part of the tattoo. • The surrounding artwork must demonstrate the concept. • 2 -3 sentences explaining the tattoo and the best location on the body for the tattoo must be written underneath the tattoo.

Energy Transfer in the Atmosphere 1. Conduction - transfer of heat through matter by molecular activity. • Heat flows from higher temperature matter to lower temperature matter 2. Convection - transfer of heat by mass movement or circulation • • Occurs in fluids The continual process of warm air rising and cool air sinking is called a convection current 3. Radiation – transfer of heat by electromagnetic waves that travel out in all directions • Does not require a medium to travel through

Energy Transfer in the Atmosphere

The Greenhouse Effect • The Greenhouse Effect – The greenhouse effect = a natural warming of both Earth’s lower atmosphere and surface from solar radiation • Major greenhouse gases = carbon dioxide & water vapor

The Greenhouse Effect

Section 3 The Hydrosphere and Biosphere

The Hydrosphere • The hydrosphere includes all of the water on or near the Earth’s surface – oceans, lakes, rivers, wetlands, polar ice caps, soil, rock layers beneath Earth’s surface

The Water Cycle • The water cycle is the continuous movement of water from the ocean atmosphere land ocean

• 1 st Stage: Evaporation is the change of a substance from a liquid to a gas – Water continually evaporates but the majority from oceans • 2 nd Stage: Condensation is the change of state from a gas to a liquid – Water vapor forms water droplets on dust particles to form clouds – heavier drops fall as rain • 3 rd Stage: Precipitation is any form of water that falls to the surface from the clouds – rain, snow, sleet, and hail

Output Page: The Water Cycle • Copy and color the water cycle

Earth’s Oceans • The World Ocean is an interconnected body of water of all the oceans – Plays an important role in the regulation of the planet’s environment!

• Pacific Ocean – Largest ocean on Earth – Deepest point on the ocean floor (Challenger Deep) in the Mariana Trench – Oceanographers separate the North and South Pacific based on the direction of the surface current flow • north of the equator move in a clockwise direction • South of the equator move counter-clockwise

• Atlantic Ocean – 2 nd largest ocean – Covers about half the area of the Pacific Ocean – Also divided into a north/south half based on directions of surface current flow • Indian Ocean – 3 rd largest ocean • Artic ocean – Smallest ocean – Much of its surface is covered by floating ice (pack ice) – forms when either waves or wind drive together frozen seawater, known as sea ice, into a large mass

Ocean Water • Ocean water contains more salts than freshwater – 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

Composition of Ocean Water

Temperature Zones • The surface zone is the top layer of the ocean – warmed by the sun • Below the surface zone is thermocline – temperature falls rapidly • The deep zone extends from thermocline to the bottom of the ocean – average 2°C

A Global Temperature Regulator • Currents transfer heat from warmer to cooler areas on Earth – Cold water currents help moderate warm temperatures of land areas – Warm water currents help moderate cold temperatures of land areas • British Isles are warmed by the waters of the Gulf Stream

Satellite Image of the Gulf Stream

Surface Currents • Surface Currents are movements of water that flow horizontally in the upper part of the ocean’s surface – wind driven – warm or cold

Output Page: Ocean Surface Currents

Deep-Ocean Circulation • Density currents = vertical currents of ocean water resulting from density differences among water masses – An increase in density can be caused by a decrease in temperature or an increase in salinity • Densest water located near Antarctica

Fresh Water and Ground Water • Fresh water contains insignificant amounts of salts – Mainly found in icecaps, glaciers, lakes, rivers, wetlands, the soil and atmosphere • Most water through precipitation trickles through the ground and collects as groundwater – makes up 1% of water BUT fulfills our freshwater needs

Aquifers • A rock layer that stores and allows the flow of groundwater

The Biosphere • The biosphere is the part of Earth where life exists – The materials that organisms require must be continually recycled – Located near Earth’s surface because most of the sunlight is available near the surface • Primary producers are plants and algae (phytoplankton) • Almost every other organism gets its food from plants and algae

Energy Flow in the Biosphere • Energy flow continuously used and recycled – When an organism dies, its body is broken down and the nutrients become available for other organisms. – Allows life on Earth to continue to exist • Closed systems are systems that cannot exchange matter or energy with its surroundings. • Open systems are systems that can exchange both matter and energy with its surroundings