3-5 Waves(Earth Book)
How Waves FormEnergy in waves comes from
wind that blows across the water’s surface!
Wave Motion Wave Motion 2
1. As the wind makes contact with the water, some of its energy transfers to the water
2. Water particles move up and down, NOT forward; the form of the wave moves forward
3. As wave approaches land, the water particles DO move forward
4. Forward-moving water shapes the coast
Erosion by Waves
ImpactEnergy in waves can break apart
rocks & make cracks larger
AbrasionAs a wave approaches shallow water, it
picks up sediment, when the wave hits land, the sediment wears away rock like sand
paper
Landforms created by
Wave Erosion
Wave-cutcliff
Waves erode base of the land
so much that the rock above
collapses
Part of the shore that sticks out into the ocean
Headland
HeadlandWaves coming to shore change direction & bend to
concentrate their energy on the headlandEventually wears it down & evens out the shore
Sea CaveWhen a soft pocket of rock surrounded by harder rock is hollowed out by wave erosion, usually in a
headland
Inside a Sea Cave
Sea ArchWhen a soft pocket of rock is hollowed right through a headland to the other side, usually a sea arch is created from a sea cave
Sea StackWhen the top of a sea arch collapses,
a pillar of rock is left behind
Sea Stack
Wave cut notch
Sea Arch
Sea Cave
Headland
Deposition by Waves
BeachAn area of wave-washed sediment along a coast.Sediment usually sand from rivers, but also coral
or seashell bits
Longshore DriftWaves coming into a beach come in at an angle not straight
on
Creates a current that is parallel to shore.
Wave
s
Current
That’s why they say if you get stuck in the “under toe” swim parallel to shore
Longshore Drift Sediment build-upMoves sediment down a beach in the direction of the
current
Spitforms
Current
A beach that projects from the shore like a finger as longshore
drift carries sediments down a
beach, the sediments get deposited when
they run into a headland or other
obstacle
Spit
SandbarLong ridges of sand parallel to the shore
Built up by incoming waves
Barrier BeachSimilar to a sandbar
Formed when storm waves pile sand above sea level
Dangerous to live on-can be swept away by a storm
2-3 Winds(Weather Book)
What is Wind?• Horizontal movement of air from an
area of high pressure (H) to an area of lower pressure (L)
• The greater the difference, the faster the wind moves
• Differences in air pressure are caused by the uneven heating of Earth
• Described by direction coming from & speed
What is Wind?
LOCAL WINDS
•Move short distances
•Can blow in any direction
•Caused by unequal heating of Earth’s surface within a small area
SEA BREEZE• Land heats up fast during day (low
pressure)
• Ocean stays cool (high pressure)
• Uneven heating creates windHL
Ocean Land
• Air moves from the ocean to the land creating a sea breeze
SEA BREEZE
LAND BREEZE• Land cools down colder than ocean
at night (high pressure)
• Ocean stays warmer than land (low pressure)
• Uneven heating creates windHL
Land Ocean
• Air moves from the land to the ocean creating a land breeze
LAND BREEZE
GLOBAL WINDS
•Winds that blow steadily from specific directions over long distances
•Caused by unequal heating of Earth’s surface over large areas
• On a hypothetical non-rotating planet, 2 large wind currents would form.
Non-Rotating Earth Model
Northern Hemispher
e&
Southern Hemispher
e
Non-Rotating Earth Model
Pause here forCoriolis
paper test
Coriolis Effect
•As Earth rotates, the Coriolis Effect turns winds in the Northern Hemisphere toward the right.
Rotation of earth
Coriolis Effect
Rotating Earth Model
•When the effect of rotation is added, the 2 cells would break into many smaller cells (wind belts).
Global Wind BeltsA series of wind belts circle Earth.Between the wind belts are calm areas where air is rising or falling.
Global Wind Belts:1. Doldrums & Horse Latitudes– very weak
winds, almost no winds, located at:00 (doldrums) and 300 (horse latitudes)
2. Trade Winds–Winds are very calm, warm and steady.
Located 00 to 300N & 300S of the equator
3. Prevailing Westerlies –Travel west to east.Strong winds located 300-600 latitude in both
hemispheres.
4. Polar Easterlies – Cold, but weak winds Located 600 to the poles
5. Jet stream – Strong, belt of high-speed, high-pressured winds. Blow from west to east.
3-6 Wind(Earth Book)
Weakest agent of erosion
Shapes land in areas with few plants to hold soil in place
WIND EROSION
DEFLATION
Process by which
wind removes surface
materials
DEFLATION
Fine particles- carried through the air (clay & silt)Medium particles-skip, bounce or jump (sand)Large particles-slide or roll (pebbles & rocks)
Desert Pavement
When all the smaller sediments (clay, silt, sand) are removed and only larger rocky
materials too heavy or large to move remain
Blowout Slight depression in the ground, deflation can create a bowl-shaped hollow
WIND DEPOSITIONWhen wind slows down or hits an obstacle,
sediments are dropped (deposited)
The stick in the picture acts as a wind obstacle. It lowers thewind speed and allows for sand to build up behind the stick.
Beach Sand Dune
Desert Sand Dune
Sand DuneCoarse wind-blown sediment that has built up
•Happens when wind hits an obstacle (clump of grass/rock)
•Seen on beaches and in deserts
•Many shapes and sizes
•Move over time shifting from one side to another
•Plant roots can anchor a dune (help keep it in place)
Loess deposit layer
Fine, wind deposited sediments
• Clay or silt• Deposited in layers• Can travel far from source• Help form fertile soil (valuable farm
land)
Major loess deposits in the U.S.