Earth Science Rocks!Warm up October 29

Question: These two photos were taken from the same place 63 years apart. How are they alike? How are they different?

1941 2004

Opening:

• Streambed DemonstrationHow does water contribute to erosion?How does gravity contribute to erosion?

Ag Upsala Glacier, South America

Grinnell Glacier, Montana

• 1935 • 2005

South Cascade Glacier, Washington

Earth Science Rocks!

• MYP Unit Question: How does land change?

• Area of Interaction: Environment

• Learner Profile: Caring and Principled

Earth Science Rocks!

• Standard: Investigate the scientific view of how the Earth’s surface is formed.

• Learning Target: Today I am learning about erosion by ice and wind because I will know how to protect my mountain house or beach house.

Erosion by Ice

• A glacier is a huge mass of ice and snow that moves over land. It erodes and deposits large amounts of rock material.

• p. 352-356

How glaciers form

• Glaciers form in very cold areas. The snow piles up year after year.

• Over time, the weight of the snow packs the snow and forms a giant mass of ice.

• Gravity causes them to flow slowly like a “river of ice”

Glacier ice is the largest reservoir of fresh water on the planet, storing an estimated 75 percent

of the world’s supply

A glacier can range in length from the equivalent of a football field to more than 100 miles.

The Antarctic ice sheet is actually a glacier. If it were to melt, sea levels would rise 210

feet

NASA image of Antartica taken from space

Though it sits on the equator, Mount Kilimanjaro is glaciated

• A single glacier ice crystal can grow to be as large as a baseball

Mountain valleys are typically “V” shaped before being taken oven by a glacier; during glaciation, the valley

widens and deepens and becomes “U” shaped.

Alaska is estimated to have more than 100,000 glaciers. Most remain unnamed.

Erosion by Wind

• Wind carries and deposits sediment. Deserts, coastlines, and areas with little plant coverage are the most affected by wind erosion.

• p. 350-351

Sand dunes at the beach

leeward leewardwindward

Piles of sand deposited by wind - Leeward side has a steeper slope

Sand Dunes

Sand Dunes in the desert

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

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 – Texas

The Dust Bowl of the 1930s

Rock formations in the Wadi Desert in Egypt

Formed when wind and water weather (erode) softer material first. Arches National Canyon, Utah

Wind carries fine particles that work like a sand blaster (i.e. sand, silt, clay, and ice particles)

Ventifact on Mt. Falconer - Canada

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

Desert pavement

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

Loess Deposits - Banks, Pennsylvania

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