Forces Cause Change

TEKS 3.6B

TEKS 3.6B

• The student knows that forces cause change. The student is expected to:

–Identify that the surface of the Earth can be changed by forces such as earthquakes and glaciers.

What is the most likely cause of the damage that you see in these photographs?

A. Wind

B. Volcano

C. Earthquake

D. Erosion

Correct Answer

• C. Earthquake

• The damage was formed when the earth’s crust was violently shaken. The crust was affected when the underlying tectonic plates suddenly moved past one another with great force.

• A. Wind• This was not caused

by the wind. You can tell in the photos that the force came from below, not above. If the force was from above, the destruction would be more widespread.

Incorrect Answer:

Incorrect Answer:

B. Volcano

This was not cause by volcanic eruption no evidence of molten lava.

Incorrect Answer:

D. Erosion

• Erosion is the pickup and removal of sediment caused by weathering. It is a gradual process and the photos show damage from a quick, violent process.

A.Wind

B.Ultraviolet radiation

C.Rain

D.Extreme changes in temperature

These rock formations, called hoodoos, are located in a canyon near a desert. Their formation occurred over many thousands of years. Which of the following is NOT a cause of their formation?

Correct Answer

• B. Ultraviolet radiation

• UV radiation is not a major cause of weathering of the surface of the Earth.

Incorrect Answer

• A. Wind

• Wind carrying sand and small rock particles is a contributing agent of weathering.

Incorrect Answer• C. Rain• Rain assists in

the breaking down of rocks into smaller pieces. Rain does contribute to the formation of the hoodoos.

Incorrect Answer

• D. Extreme changes in temperature

• Extreme temperature changes causes frost action, the repeated freezing and thawing of water, which physically breaks down the rock.

A.Cause acid rain

B.Completely melt each summer

C.Cause large earthquakes

D.Carry away rock and soil

One day this V-shaped valley may become a U-shaped valley. This will happen because the glacier will:

Correct Answer

• D. Carry away rock and soil

• Glacier movement transports sediment and removes rock and soil from the valley during its movement. This will lead to the V-shaped valley becoming a U-shaped valley.

Incorrect Answer

• A. Acid Rain

• Glaciers do not cause acid rain.

Incorrect Answer

• B. Completely melt each summer

• Glaciers do not completely melt each summer.

Incorrect Answer

• C. Cause large earthquakes

• Glaciers do not cause earthquakes

What evidence do you see that glaciers have eroded the Earth’s surface?

A. Rock fragments and sediments

B. Large sheets of ice

C. Uplift of nearby land masses

D. Formation of icebergs

Correct Answer

• A. Rock fragments and sediments

• As glaciers move, rock fragments and sediments are carried by the glacier and deposited a the sides or the front of the glacier.

Incorrect Answer

• B. Large sheets of ice

• This is the definition of a glacier, not evidence that the glacier eroded the Earth’s surface.

Incorrect Answer

• C. Uplift of nearby land masses

• Glaciers compact land masses as the weight of the glacier increases. Uplift is caused by plate tectonics.

Incorrect Answer

• D. Formation of icebergs

• Icebergs form when the glaciers reach the coast line and break off into the sea. This is not erosion.

Photo Credits

• All photos were obtained from:

• http://libraryphoto.er.usgs.gov/earth1.htm

• “The photographs are not copyrighted and may be viewed and downloaded free of charge.”