Forces That Change Our World

Students will identify surface features of the Earth caused by constructive and destructive processes. a. Identify surface features caused by constructive processes.

• Deposition (Deltas, sand dunes, etc.) • Earthquakes • Volcanoes • Faults

Identify and find examples of surface features caused by destructive processes• Erosion (water—rivers and oceans, wind)

• Weathering • Impact of organisms • Earthquake

c. Relate the role of technology and human intervention in the control of constructive and destructive processes. Examples include, but are not limited to

• Seismological studies, • Flood control, (dams, levees, storm drain management, etc.) • Beach reclamation (Georgia coastal islands)

I am a force that wears away soil during a rainstorm. What am I?

Water

I am the process of breaking down rock into smaller pieces. What process am I?

Weathering

I am a huge sheet of ice that scrapes away tops of mountains. What am I?

Glacier

I seep into rock cracks and crevices as water. When the weather drops below 32 degrees, I have the power to split a rock in two. What am I?

Ice

I am the process of movement. I move material from one place to another. What process am I?

Erosion

I am usually at work in the desert. I use sand to grind rock into dust. What am I?

Wind

Once material has been moved, it sometimes gets dropped off. This process is my name. What process am I?

Deposition

True or False. Weathering always happens before Erosion.

False. For example, while wind erodes sand across the desert, it grinds against rock formation and weathers it at the same time.

Deltas are formed when rivers flow towards the sea carrying soil, rock, and sediment. These materials sink to the bottom of the river and over time form new land. Deltas are formed by the

process of _______.

Deposition

True or False. In order for material to be depositioned, it must be eroded first.

True. Deposition is when material is dropped off in another place after being moved.

True or False. Gravity can act as an eroding process.

True. The force of gravity can pull rock and debris from higher places to lower places.

Mount Rushmore is carved in stone. Ice has frozen in cracks and damaged some of the structure. What process is this?

Weathering

Stone Mountain, GA was once underground. Gradually the land was worn away that covered the granite underneath. The granite rock expanded forming cracks. Huge slabs of rock broke off, leaving a smooth surface. What two agents wore most of the soil away?

Wind and water

Rainbow Bridge is a natural wonder. The bridge was probably formed by what two things?

Wind and sandWind and water

As the ocean pounds away at seaside cliffs, rock, sand, and soil is washed away. This is an example of ____________.

Weathering

Mass movement is erosion on a very large scale. Name two examples of mass movement from the chapter.

Mudslides, Landslides, creep, sinkholes

In the dust bowl of the early 1900’s, wind blew up to 3 feet of soil away. This was an example of ____________.

Erosion

Explain the difference between weathering and erosion.

Weathering is breaking down rock. Erosion is moving it.

Stone Mountain, GA was once underground. Gradually the land was worn away that covered the granite underneath. The granite rock expanded forming cracks. Huge slabs of rock broke off, leaving a smooth surface. What probably caused the huge slabs to break off?

Ice expanding the cracks

Think about what you know of human activities. What types of human activities increase the amount of erosion that takes place?

Tilling soil for farming loosens it so the wind and water can erode it.

Land developers clear land to build cities and housing developments.