Ch. 16 Dynamic Ocean

Report
Ch. 16
SC.912.N.1.1, SC.912.N.2.5
SC.912.E.6.5, SC.912.E.7.2, SC.912.E.7.3 , SC.912.E.7.4 ,
SC.912.E.7.9
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Explain how surface currents develop.
Describe how ocean currents affect climate.
State the importance of upwelling.
Describe the formation of density currents.
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Ocean current
Surface current
Gyre
Coriolis Effect
Upwelling
Density current
1.
2.
3.
4.
How do surface currents develop?
How do ocean currents affect climate?
Why is upwelling important?
How are density currents formed?
http://www.cleanvideosearch.com/media/action/yt/watc
h?videoId=3niR_-Kv4SM
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Ocean current is the mass of ocean water that
flows from one place to another.
Surface currents are movements of water that
flow horizontally in the upper part of the
ocean’s surface.
Surface currents develop from friction between
the ocean and the wind that blows across its
surface.
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• Gyres are huge circular-moving current
systems that dominate the surfaces of the
oceans.
The Coriolis effect is the deflection of
currents away from their original course
as a result of Earth’s rotation.
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When currents from low-latitude regions move
into higher latitudes, they transfer heat from
warmer to cooler areas on Earth.
As cold water currents travel toward the
equator, they help moderate the warm
temperatures of adjacent land areas.
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Upwelling is the rise of cold water from deeper
layers to replace warmer surface water.
Upwelling brings greater concentrations of
dissolved nutrients, such as nitrates and
phosphates, to the ocean surface.
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Density currents are vertical currents of
ocean water that result from density differences
among water masses.
An increase in seawater density can be caused
by a decrease in temperature or an increase in
salinity.
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High Latitudes
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Most water involved in deep-ocean currents begins
in high latitudes at the surface.
Evaporation
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Density currents can also result from increased
salinity of ocean water due to evaporation.
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In a simplified model, ocean circulation is
similar to a conveyor belt that travels from the
Atlantic Ocean, through the Indian and Pacific
Oceans, and back again.
http://www.cleanvideosearch.com/media/action/yt/watc
h?videoId=Ca4eRt2wwg8
You have 15 minutes to answer the questions from this
section. Be prepared to discuss your answers.
Surface currents develop from friction
between the ocean and the wind that blows
across its surface.
Warm water currents that come from
equatorial regions transfer heat to cooler
areas of Earth; for example the Gulf Stream
and North Atlantic currents warm
northwestern Europe in the winter months.
Cold water currents from the poles
moderate warm temperatures of adjacent
land areas.
Upwelling brings dissolved nutrients to
the ocean surface, providing the necessary
nutrients for phytoplankton to undergo
photosynthesis. This productivity
supports the extensive populations of fish
and other organisms.
They are formed when the density of water
changes due to a change in salinity and
temperature.
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Describe how ocean waves get energy.
State three factors that determine
characteristics of a wave.
Describe how energy moves through a wave.
Explain the forces that produce tides.
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Wave height
Wave length
Wave period
Fetch
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Tide
Tidal range
Spring tide
Neap tide
http://www.cleanvideosearch.com/media/action/yt/watc
h?videoId=l1WF8b6HZLM
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Purpose – Students will see that wave energy
travels without causing individual particles of
the medium to move very much.
Materials – Slinky toy
Procedure – Have a student hold one end of a
slinky without moving it. Stretch the slinky
out, gather a few rings together, release them
all at once while still holding the end of the
slinky in your hand.
1.
2.
3.
4.
5.
From where do ocean waves obtain energy?
What three quantities are used to describe a
wave?
How does energy move by means of a wave?
What force produces tides?
What are three typical tidal patterns?
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Most ocean waves obtain their energy and
motion from the wind.
The wave height is the vertical distance
between the trough and crest.
The wavelength is the horizontal distance
between two successive crests or two
successive troughs.
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The wave period is the time it takes one full
wave—one wavelength—to pass a fixed
position.
Fetch is the distance that the wind has traveled
across open water.
The height, length, and period that are
eventually achieved by a wave depend on
three factors: (1) wind speed, (2) length of time
the wind has blown, and (3) fetch.
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Circular orbital motion allows energy to move
forward through the water while the individual
water particles that transmit the wave move
around in a circle.
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Changes occur as a wave moves onto shore.
As the waves touch bottom, wave speed
decreases. The decrease in wave speed
results in a decrease in wavelength and an
increase in wave height.
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Tides are daily changes in the elevation of the
ocean surface.
Ocean tides result from the gravitational
attraction exerted upon Earth by the moon and,
to a lesser extent, by the sun.
Tide-Causing Forces
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The force that produces tides is gravity.
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Tidal range is the difference in height between
successive high and low tides.
Spring tides are tides that have the greatest
tidal range due to the alignment of the Earth–
moon–sun system.
Neap tides are tides that have the lowest tidal
range, occurring near the times of the firstquarter and third-quarter phases of the moon.
SPRING TIDES
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When the Earth, Moon,
and Sun are aligned we
experience Spring
Tides.
New Moon & Full
Moon
NEAP TIDES
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When Earth, Moon, and
Sun are at right angles
to each other, we
experience Neap Tides.
First Quarter & Third
Quarter
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Three main tidal patterns exist worldwide:
diurnal tides, semidiurnal tides, and mixed
tides.
You have 15 minutes to answer the questions from this
section. Be prepared to discuss your answers.
Waves obtain their energy from wind.
Three qualities used to describe waves are:
wind speed, the length of time the wind
has blown, and fetch.
Circular motion allows energy to move
forward through a wave, while the
individual water particles that transmit the
wave move around in a circle.
Gravity is the force that produces tides.
The three tidal patterns are: diurnal,
semidiurnal, and mixed.
SC.912.N.1.1, SC.912.N.2.5
SC.912.E.6.5, SC.912.E.7.2, SC.912.E.7.3 , SC.912.E.7.4 ,
SC.912.E.7.9
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List the agents responsible for the movement of
sediments along the shoreline.
Explain how refraction affects wave action
along the shore.
Describe the processes that form shoreline
features.
List the structures that can be built to protect a
shoreline.
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Beach
Wave refraction
Longshore currents
Barrier islands
1.
2.
3.
4.
5.
How does refraction affect wave action along
the shore?
What do longshore currents do?
By which processes do shoreline features
form?
What structures can be built to protect a
shoreline?
What is beach nourishment?
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A beach is the accumulation of sediment found
along the shore of a lake or ocean.
Waves along the shoreline are constantly
eroding, transporting, and depositing sediment.
Many types of shoreline features can result
from this activity.
WAVE IMPACT
The impact of large, highenergy waves against
the shore can be
awesome in its violence.
Each breaking wave
may hurl thousands of
tons of water against
the land, sometimes
causing the ground to
tremble.
ABRASION
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Abrasion is the sawing
and grinding action of
rock fragments in the
water.
Abrasion is probably
more intense in the surf
zone than in any other
environment.
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Wave refraction is the bending of waves, and
it plays an important part in the shoreline
process.
Because of refraction, wave energy is
concentrated against the sides and ends of
headlands that project into the water, whereas
wave action is weakened in bays.
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A longshore current is a near-shore current
that flows parallel to the shore.
Turbulence allows longshore currents to easily
move fine suspended sand and to roll larger
sand and gravel particles along the bottom.
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Shoreline features that originate primarily from
the work of erosion are called erosional
features. Sediment that is transported along
the shore and deposited in areas where energy
is low produces depositional features.
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Wave-Cut Cliffs and Platforms
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Wave-cut cliffs result from the cutting action of the
surf against the base of coastal land. A flat, benchlike, wave-cut platform forms in front of the wave-cut
cliff.
Sea Arches and Sea Stacks
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When two caves on opposite sides of a headland
unite, a sea arch results. Eventually, the arch falls in,
leaving an isolated remnant, or sea stack, on the
wave-cut platform.
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Where longshore currents and other surf zone
currents are active, several features related to
the movement of sediment along the shore
may develop.
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A spit is an elongated ridge of sand that
projects from the land into the mouth of an
adjacent bay.
A baymouth bar is a sandbar that completely
crosses a bay.
A tombolo is a ridge of sand that connects an
island to the mainland or to another island.
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Barrier islands are narrow sandbars parallel
to, but separate from, the coast at distances
from 3 to 30 kilometers offshore.
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Protective Structures
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Groins, breakwaters, and seawalls are some
structures built to protect a coast from erosion or to
prevent the movement of sand along a beach.
Beach nourishment
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Beach nourishment is the addition of large quantities
of sand to the beach system.
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Groins are structures built at right angles to the
shore to trap sand moving parallel to the shore
to maintain beaches.
Seawalls are structures built parallel to shore
that shields the coast from breaking waves.
You will need to write 10 facts from the video.
You have 15 minutes to answer the questions from this
section. Be prepared to discuss your answers.
Wave energy is concentrated against the
sides of headlands, and it is weakened in
the bays.
Longshore currents move fine suspended
sand and roll larger sand and gravel along
the bottom and along the shore.
Waves erode, transport, and deposit
sediment, forming many shoreline
features.
Groins, breakers, and seawalls are
structures built to protect the shoreline.
Beach nourishment is an approach to
stabilize the shoreline by adding large
quantities of sand to the beach system.

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