ocean currents ocean waves tides

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Movement of Oceans Movement of Oceans Ocean currents Ocean currents Ocean Waves Ocean Waves Tides Tides

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22.1 Ocean Currents Currents-mov’t of ocean waters in giant streams. Two types of major currents are surface and deep currents.

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Page 1: Ocean currents Ocean Waves Tides

Movement of Movement of OceansOceansOcean currentsOcean currentsOcean WavesOcean WavesTidesTides

Page 2: Ocean currents Ocean Waves Tides

22.1 Ocean Currents22.1 Ocean Currents Currents-mov’t of ocean waters in giant Currents-mov’t of ocean waters in giant

streams.streams. Two types of major currents are surface Two types of major currents are surface

and deep currents.and deep currents.

Page 3: Ocean currents Ocean Waves Tides

Surface CurrentsSurface Currents Move on or near the surface of ocean Move on or near the surface of ocean

and are driven by winds.and are driven by winds.

Page 4: Ocean currents Ocean Waves Tides

Deep CurrentsDeep Currents Move more slowly beneath the surface of Move more slowly beneath the surface of

the ocean and are caused by differences the ocean and are caused by differences in the density of water.in the density of water.

Page 5: Ocean currents Ocean Waves Tides

Surface currentsSurface currents Wind is the driving force.Wind is the driving force. Most are the result from global wind Most are the result from global wind

patterns.patterns.

Page 6: Ocean currents Ocean Waves Tides

Factors affecting ocean Factors affecting ocean surface currentssurface currents

Controlled by wind belts, earth’s rotational Controlled by wind belts, earth’s rotational effects, and location of the continents.effects, and location of the continents.

Global wind belts that most directly affect the Global wind belts that most directly affect the flow of surface currents are trade winds and flow of surface currents are trade winds and westerlies.westerlies.

Trade winds located n & s of equator.Trade winds located n & s of equator. Westerlies are located in the middle latitudes.Westerlies are located in the middle latitudes.

Page 7: Ocean currents Ocean Waves Tides

Trade windsTrade winds Northern Hemisphere, they blow from Northern Hemisphere, they blow from

southwest, pushing currents eastward southwest, pushing currents eastward across the Atlantic and Pacific.across the Atlantic and Pacific.

Southern Hemisphere, they blow from the Southern Hemisphere, they blow from the northwest, pushing the West Wind Drift, northwest, pushing the West Wind Drift, around the world. around the world.

West Wind Drift is the earth’s largest West Wind Drift is the earth’s largest current.current.

Page 8: Ocean currents Ocean Waves Tides

CoriolisCoriolis Another factor controlling surface Another factor controlling surface

currents.currents. It is the deflection of the earth’s winds It is the deflection of the earth’s winds

and ocean currents caused by the earth’s and ocean currents caused by the earth’s rotation.rotation.

Creates huge circles of moving water Creates huge circles of moving water called Gyres.called Gyres.

Page 9: Ocean currents Ocean Waves Tides

GyreGyre Huge circles of moving waterHuge circles of moving water Winds flow counterclockwise in Southern Winds flow counterclockwise in Southern

Hemisphere.Hemisphere. Winds flow clockwise in the Northern Winds flow clockwise in the Northern

Hemisphere.Hemisphere.

Page 10: Ocean currents Ocean Waves Tides

Third Major FactorThird Major Factor Continent is the third major factor that Continent is the third major factor that

effects surface currents.effects surface currents. When current flows against a landmass, When current flows against a landmass,

it is deflected and divided.it is deflected and divided.

Page 11: Ocean currents Ocean Waves Tides

Equatorial & Equatorial Equatorial & Equatorial Countercurrent CurrentsCountercurrent Currents

Warm water currents found in the Pacific, Warm water currents found in the Pacific, Atlantic, and Indian Oceans. Flows Atlantic, and Indian Oceans. Flows westward.westward.

Weaker current that lies between these Weaker current that lies between these westward flowing currents. It flows westward flowing currents. It flows eastward.eastward.

Page 12: Ocean currents Ocean Waves Tides

Gulf StreamGulf Stream Swift warm current that pushes water through Swift warm current that pushes water through

the Caribbean Sea and the Gulf of Mexico. It the Caribbean Sea and the Gulf of Mexico. It also flows around the tip of Florida and up the also flows around the tip of Florida and up the eastern seaboard.eastern seaboard.

Meets the cold waters of the Labrador Meets the cold waters of the Labrador Currents.Currents.

Widens and speed decreases south of Widens and speed decreases south of Greenland, until it becomes the North Atlantic Greenland, until it becomes the North Atlantic Drift.Drift.

Page 13: Ocean currents Ocean Waves Tides

North Atlantic DriftNorth Atlantic Drift Vast, slow moving warm current that Vast, slow moving warm current that

comes off of the Gulf Stream.comes off of the Gulf Stream. A drift is a weak current.A drift is a weak current. It splits and one part becomes the It splits and one part becomes the

Norway Current off the coast of Norway.Norway Current off the coast of Norway. The other current split becomes the The other current split becomes the

Canary Current.Canary Current.

Page 14: Ocean currents Ocean Waves Tides

Four Currents that form Four Currents that form the North Atlantic Gyrethe North Atlantic Gyre

Gulf StreamGulf Stream Canary CurrentCanary Current North Atlantic DriftNorth Atlantic Drift North Atlantic Equatorial CurrentNorth Atlantic Equatorial Current Center of the gyre lies the Sargasso Sea.Center of the gyre lies the Sargasso Sea. Sargasso Sea is a vast area covered in Sargasso Sea is a vast area covered in

brown seaweed called Sargassum float.brown seaweed called Sargassum float.

Page 15: Ocean currents Ocean Waves Tides

Japan CurrentJapan Current Pacific equivalent of the Gulf Stream.Pacific equivalent of the Gulf Stream. Flows northward along the east coast of Flows northward along the east coast of

Asia.Asia.

Page 16: Ocean currents Ocean Waves Tides

California CurrentCalifornia Current Waters from the Japan Current flow Waters from the Japan Current flow

toward the North America as the North toward the North America as the North Pacific Drift, eventually flowing southward Pacific Drift, eventually flowing southward as the cool California Current. as the cool California Current.

Along the California coastAlong the California coast

Page 17: Ocean currents Ocean Waves Tides

Currents in Southern Currents in Southern HemisphereHemisphere

Move counterclockwise.Move counterclockwise. In southern regions of the big three In southern regions of the big three

oceans, constant westward winds oceans, constant westward winds produce the West Wind Drift.produce the West Wind Drift.

Largest current in the world.Largest current in the world.

Page 18: Ocean currents Ocean Waves Tides

Patterns of Surface Patterns of Surface Currents in Indian OceanCurrents in Indian Ocean

Southern part-currents follow a circular, Southern part-currents follow a circular, counterclockwise gyre.counterclockwise gyre.

Northern part-currents are governed by Northern part-currents are governed by winds called monsoons.winds called monsoons.

Monsoons are winds which change Monsoons are winds which change direction with the seasons.direction with the seasons.

Page 19: Ocean currents Ocean Waves Tides

Deep CurrentsDeep Currents Movement of polar waters is the result of Movement of polar waters is the result of

density differences.density differences. Water molecules contract, when the Water molecules contract, when the

water is cooled.water is cooled. Water molecules expand, when water is Water molecules expand, when water is

warmed.warmed. Higher density of polar waters is a result Higher density of polar waters is a result

of an increase in salinity of water.of an increase in salinity of water.

Page 20: Ocean currents Ocean Waves Tides

Antarctic Bottom WaterAntarctic Bottom Water Close to freezing temperature.Close to freezing temperature. Salinity is higher.Salinity is higher. These two factors make the water off the These two factors make the water off the

coast of Antarctica the densest and coast of Antarctica the densest and coldest ocean water in the world.coldest ocean water in the world.

Page 21: Ocean currents Ocean Waves Tides

Turbidity CurrentsTurbidity Currents Are thought to cause the deepening of Are thought to cause the deepening of

submarine canyons.submarine canyons. Deep ocean currents are the result of Deep ocean currents are the result of

changes in density of ocean water.changes in density of ocean water.

Page 22: Ocean currents Ocean Waves Tides

Bell RingerBell RingerPassage 2 and questions 8 on Tuesday. Passage 2 and questions 8 on Tuesday. Pg 44-45Pg 44-45Earth Science test on chapter 22 will be Earth Science test on chapter 22 will be Friday from worksheets and chapter Friday from worksheets and chapter questions.questions.Study Guide for 9wks test will be given out Study Guide for 9wks test will be given out Friday. Use your old notes to answer. Friday. Use your old notes to answer.

Page 23: Ocean currents Ocean Waves Tides

22.2 Ocean Waves22.2 Ocean Waves A wave is a periodic up and down A wave is a periodic up and down

movement of water.movement of water. Way of transferring energy.Way of transferring energy.

Page 24: Ocean currents Ocean Waves Tides

2 Parts of a wave2 Parts of a wave Crest-highest point of a wave.Crest-highest point of a wave. Trough is the lowest point between two Trough is the lowest point between two

crests.crests. Scientists study to learn characteristics.Scientists study to learn characteristics.

Page 25: Ocean currents Ocean Waves Tides

Wave TermsWave Terms Wave height is vertical distance between Wave height is vertical distance between

the crest and trough of a wave.the crest and trough of a wave. Wavelength is the horizontal distance Wavelength is the horizontal distance

between two consecutive crests or between two consecutive crests or between two consecutive troughs.between two consecutive troughs.

Wave period is the time it takes for one Wave period is the time it takes for one complete wavelength to pass a given complete wavelength to pass a given point.point.

Page 26: Ocean currents Ocean Waves Tides

Wave speedWave speed = wavelength/perod= wavelength/perod Example:Example: Wavelength of 216 m and a period of 12 Wavelength of 216 m and a period of 12

s has a speed of: 216 m/12 s= 18m/ss has a speed of: 216 m/12 s= 18m/s

Page 27: Ocean currents Ocean Waves Tides

SwellSwell Group of long, rolling waves that are all Group of long, rolling waves that are all

the same size.the same size. Move in groupsMove in groups One following anotherOne following another

Page 28: Ocean currents Ocean Waves Tides

Factors determining the Factors determining the size of wavessize of waves

Speed of the wind blowingSpeed of the wind blowing Length of time that the wind blowsLength of time that the wind blows The fetch or Length of open water, The fetch or Length of open water,

across which the wind blows.across which the wind blows.

Page 29: Ocean currents Ocean Waves Tides

FetchFetch Is the distance that the wind can blow Is the distance that the wind can blow

across open water.across open water.

Page 30: Ocean currents Ocean Waves Tides

WhitecapsWhitecaps Crest of a wave that is blown off by high Crest of a wave that is blown off by high

winds. Pg. 435winds. Pg. 435

Page 31: Ocean currents Ocean Waves Tides

FACTFACT Height of a wave changes as the wave Height of a wave changes as the wave

approaches the shore.approaches the shore. Water involved in the up and down Water involved in the up and down

motion of a wave extents to a depth of motion of a wave extents to a depth of one-half wavelength.one-half wavelength.

Top of the wave continues to move at its Top of the wave continues to move at its original speed.original speed.

Page 32: Ocean currents Ocean Waves Tides

BreakerBreaker A foamy mass of water that washes onto A foamy mass of water that washes onto

shore. shore. Height of the wave is one to two times Height of the wave is one to two times

the height of the original wave.the height of the original wave.

Page 33: Ocean currents Ocean Waves Tides

Factors that determines the Factors that determines the size & force of breakerssize & force of breakers

By the original wave height, wavelength, By the original wave height, wavelength, & the steepness of the ocean floor close & the steepness of the ocean floor close to the shore.to the shore.

Page 34: Ocean currents Ocean Waves Tides

RefractionRefraction Bending of a wave.Bending of a wave. Occurs when the part of the wave Occurs when the part of the wave

nearest the shore strikes the shallow nearest the shore strikes the shallow bottom and slows down.bottom and slows down.

Page 35: Ocean currents Ocean Waves Tides

UndertowUndertow When water carries onto a beach by When water carries onto a beach by

breaking waves is pulled back into breaking waves is pulled back into deeper water by an irregular current.deeper water by an irregular current.

Seldom very strong and only along Seldom very strong and only along shorelines with steep drop-offs do they shorelines with steep drop-offs do they create problems.create problems.

Page 36: Ocean currents Ocean Waves Tides

Rip currentRip current Dangerous undertowDangerous undertow Swift rip currents form when water from Swift rip currents form when water from

large breakers returns to the ocean through large breakers returns to the ocean through channels in underwater sandbars.channels in underwater sandbars.

Flow perpendicular to shoreFlow perpendicular to shore May be strong enough to carry a swimmer.May be strong enough to carry a swimmer. Could close beaches.Could close beaches.

Page 37: Ocean currents Ocean Waves Tides

Longshore currentLongshore current These waves are the result of waves that These waves are the result of waves that

approach the beach at angles.approach the beach at angles. Forms a sandbarForms a sandbar

Page 38: Ocean currents Ocean Waves Tides

TsunamisTsunamis Caused by underwater earthquakes.Caused by underwater earthquakes. Most destructive waves in the ocean.Most destructive waves in the ocean. Often called tidal waves.Often called tidal waves.

Page 39: Ocean currents Ocean Waves Tides

Waves that slowWaves that slow Waves slow down in shallow water Waves slow down in shallow water

because the bottom of the wave touches because the bottom of the wave touches the ocean floor and is slowed by friction.the ocean floor and is slowed by friction.

Page 40: Ocean currents Ocean Waves Tides

22.3 Tides22.3 Tides The daily changes in the level of the ocean The daily changes in the level of the ocean

surface.surface. Sir Issac Newton identified the force that Sir Issac Newton identified the force that

causes the rise and fill of tides along causes the rise and fill of tides along coastlines.coastlines.

Gravitational pull of the moon on the earth Gravitational pull of the moon on the earth and the water.and the water.

Pull is the strongest on the side of the earth Pull is the strongest on the side of the earth nearest the moon. Ocean bulges on that nearest the moon. Ocean bulges on that side.side.

Page 41: Ocean currents Ocean Waves Tides

Other factsOther facts Bulging ocean forms a high tide inside the Bulging ocean forms a high tide inside the

bulge.bulge. Low tides are formed halfway between the Low tides are formed halfway between the

two high tides.two high tides.

Page 42: Ocean currents Ocean Waves Tides

TidesTides Tidal bulges move westward.Tidal bulges move westward. Two tidal budges in most places causes two Two tidal budges in most places causes two

high tides and tow low tides daily.high tides and tow low tides daily.

Page 43: Ocean currents Ocean Waves Tides

Tidal RangeTidal Range The difference between the levels of the The difference between the levels of the

high and low tides at a specific location.high and low tides at a specific location. It can vary widely from place to place.It can vary widely from place to place. Cycles of high and low tides occur 50 min Cycles of high and low tides occur 50 min

later each day because the moon rises later each day because the moon rises about 50 minutes each day.about 50 minutes each day.

Suns gravitational pull also has an effect Suns gravitational pull also has an effect on the tidal range.on the tidal range.

Page 44: Ocean currents Ocean Waves Tides

Spring tidesSpring tides Combined gravitational pull of the sun, Combined gravitational pull of the sun,

and the moon are all aligned.and the moon are all aligned. Results in higher high tides and lower low Results in higher high tides and lower low

tides.tides. Daily range is larger at these times.Daily range is larger at these times. Occurs twice a month. Occurs twice a month.

Page 45: Ocean currents Ocean Waves Tides

Neap tidesNeap tides When the sun and moon are at right When the sun and moon are at right

angles during the first and third quarter, angles during the first and third quarter, the gravitational forces do not act the gravitational forces do not act together, instead against each other. together, instead against each other.

Daily tidal range is small.Daily tidal range is small. Occur twice a month.Occur twice a month.

Page 46: Ocean currents Ocean Waves Tides

Tidal oscillationsTidal oscillations Slow, rocking motions of ocean water Slow, rocking motions of ocean water

that occur as the tidal bulges move that occur as the tidal bulges move around the ocean basins.around the ocean basins.

Page 47: Ocean currents Ocean Waves Tides

Tidal currentTidal current As water rises and falls with the tides, it flows As water rises and falls with the tides, it flows

toward and away from the coast. toward and away from the coast. Tidal current flowing toward the coast is called Tidal current flowing toward the coast is called

the flood tide.the flood tide. Tidal current flowing toward the ocean is Tidal current flowing toward the ocean is

called the ebb tide.called the ebb tide. Slack water is the time period between flood Slack water is the time period between flood

tide and ebb tide with no tidal currents.tide and ebb tide with no tidal currents.

Page 48: Ocean currents Ocean Waves Tides

Tidal boreTidal bore The surge of water that rushes upstream.The surge of water that rushes upstream. It enters the ocean through a long bay.It enters the ocean through a long bay. Can rise as high as 5 m.Can rise as high as 5 m.

Page 49: Ocean currents Ocean Waves Tides

Factors influencing tidal Factors influencing tidal patterns in a location:patterns in a location:

Size, shape, depth, and location of the Size, shape, depth, and location of the basin in which the tide occurs.basin in which the tide occurs.