Warm-Up October 28

The Grand Canyon is an example of a young, middle-

aged, or old river?How do you know?

Old, the river bed is U-shaped.

EARTH SCIENCE ROCKS! MYP Unit Question: How does land change?

Area of Interaction: Environment

Learner Profile: Caring and Principled

Standard: Investigate the scientific view of how

the Earth’s surface is formed.

Bell Ringer: Fastest Wind on Earth

Learning Target: Today I’m learning about erosion by wind because I want to understand how to prevent it.

Work Session: Notes – Erosion by Wind

Closing: Erosion Song

On April 12, 1934 at the Mount Washington Observatory in New Hampshire the staff were busy recording wind speeds as an intense storm moved in. Early in the morning wind speeds exceeding 100 MPH were recorded and they continued to increase, it wasn't long till the wind hit speeds of 150 MPH. As the day wore on the winds topped 200 MPH with frequent gusts reaching 220 MPH.

Fastest Wind in the World

Everything is covered with rime, a kind of ice that forms when water droplets freeze on a cold surface.

Then it happened . . . at 1:21pm on April

12, 1934 a wind gust was recorded at 231 MPH or 372 KM/H, the fastest surface

wind speed ever recorded on Earth.

EROSION BY WIND Wind carries and deposits sediment. The amount and the size of particles the wind can carry depend on the wind speed.

Deserts, coastlines, and areas with little plant coverage are the most affected by wind erosion.

p. 350-351

In areas where strong winds occur, sand grains knock into one another, some grains bounce up in the air, fall forward, and hit other sand grains. (Abrasion)

Sand dunes • form from material

deposited by wind.

SAND DUNES AT THE BEACH

Example:

SAND DUNES IN THE DESERTExample:

leeward

windward

Sand DunesExample:

Barchan dunes of the Namib Desert

Crescent shaped dunes formed from a unidirectional (one-direction) wind.

Barchan dune east of Gilf Kebir Plateau Saudi Arabia

Example:

Ripple marks are miniature dunes within a dune (not more than 2 inches tall). Formed by cross winds and appear to be traveling in a different direction than the large dune.

Hueco Bolson Desert – TexasExample:

ROCK FORMATIONS IN THE WADI DESERT IN EGYPT

Example:

Formed when wind and water weather (erode) softer material first.

Arches National Canyon, UtahExample:

Wind carries fine particles that work like a sand blaster

(i.e. sand, silt, clay, and ice particles)

Ventifact on Mt. Falconer - Canada Example:

Formed in arid environments when wind carries finer, more lightweightparticles such as sand away. Large particles are left behind and protectfrom further erosion.

Desert pavementExample:

Yellowish, fine grained silt and clay sized particles formed by glaciers millions of years ago; carried and deposited by wind.

Loess Deposits - Banks, PennsylvaniaExample:

Base of a rock is weathered and eroded

more quickly due to sand blasting.

Sand grains can only be picked up a couple

of feet.

Pedestal rockAfrica

Example:

EROSION BY HUMAN ACTIVITYHuman activity causes 10 times more erosion of the continental surface of the Earth than all natural processes combined.

WHY DOES THIS MATTER? Earth's surface involves a balanced process,

where new soil forms at about the same rate as it erodes.

If humans are stripping soil at that rate, nature won't be able to keep up.

WHY IS THIS CRITICAL?TWO REASONS

1. The Earth's human population is growing

rapidly.

2. Almost all the land that is capable of producing crops is being used.

WHAT CAN WE DO?

SOIL CONSERVATION--TERRACING

Banaue rice terraces in the Philippines

SOIL CONSERVATION—CROP ROTATION

Crop Rotation

George Washington Carver

THE DUST BOWL OF THE 1930S

CHECK EACH PAGECover—definition of Erosion

Booklet pages notes quality drawings Labels

Standards Check Exit Ticket

CLOSING: EROSION SONG