3-5 waves (earth book). how waves form energy in waves comes from wind that blows across the...

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.