Transcript Waves and Wind

Waves and Wind
Chapter 3
Section 3
Standard
 S 6.2 a Surface water flow, glaciers, wind and ocean
waves have all been an continue to be active
throughout California and the rest of the world in
shaping landscapes.
 S6.2c Students know beaches are dynamic systems
in which the sand is supplied by rivers and moved
along the coast by the action of waves.
Anticipatory Set
Vocabulary
 Headland
 Beach
 Longshore drift
 Spit
 Sand dune
 Deflation
 loess
Input
 The energy in waves comes from wind that blows across the
water’s surface.
 The energy that water picks up from the wind, causes water
particles to move up and down as the wave goes by.
 A wave changes as it approaches land.
 Deep water- wave only affects the water near the surface
 Shallow water- wave begins to drag on the bottom and it
causes the wave to slow down
Erosion by Waves
 Waves shape the coast through erosion by breaking
down rock and transporting sand and other
sediment.
 Impact- large waves hit the rocks along the shore and
break them part. Over time pieces of the rock fall off.
 Waves coming to shore change direction.
 Headland- part of the shore that sticks out into the
ocean. Made up of harder rocks
 When waves hit a steep, rocky coast they strike the
area again and again.
 It will begin to erode and make a cut. Each time it
strikes the cut is getting bigger and bigger.
 Eventually, waves erode the base of a cliff so much
that the rock collapse.
 Wave- cut cliff= waves erode the soft rock along the
base of a steep coast and the results is a new
landform called a wave-cut cliff
Deposits by Waves
 Waves shape a coast when they deposit sediment, forming
coastal features such as beaches, spits, sandbars, and barrier
beaches.
 Beach- an area of wave washed sediment along a coast.
Usually sand is left behind.
 Beaches are constantly changing- supply of sand and wave
motion.
 Long shore drift- when waves hit the beach, the beach
sediment moves down the beach with the current
 Spits- a beach that projects
like a finger out in the
water.
 Barrier Beach- forms when
storm waves pile up large
amounts of sand above
sea level forming a long,
narrow island parallel to
the coast.
 Silver Strand Beach in
California is a great
example of a barrier
beach.
 Some people have built
homes on barrier beaches.
 A fast flowing river would mostly likely lift sand
sized particles of sediment and carry them
downstream
Erosion by Wind
 Sand dune- is a deposit of wind blown sand.
 Wind cause erosion by deflation and abrasion.
 Wind is the weakest agent of erosion
 In a desert, it is constantly changing.
 Deflation- the process by which wind removes surface
materials
 The strong the wind, the larger the sand particles it can
pick up.
Deposition by Wind
 Abrasion- wind carried sand can polish rocks, but it causes
little erosion.
 Wind erosion and deposition may form sand dunes and
loess deposits.
 Wind carrying sand grains deposits the sand when the
wind slows down or hits an obstacle.
 Loess- fine, wind deposited sediment. Particles of clay and
silt eroded and deposited by the wind.
 Mojave Desert’s desert pavement was created through the
process known as deflation.
Checking for
Understanding
 What are 2 kinds of wind erosion?
 How does an ocean wave change when it reaches
shallow water?
 What are 2 ways in which waves cause erosion?
Guided Practice
Independent Practice
 Guided Practice: Page 67 of Wave worksheet
 First, intrapersonally.
 Second, with a partner interpersonally.
 Independent Practice: Wave Worksheet