Destructive Forces

• S5E1. Students will identify surface features of the Earth caused by constructive and destructive processes. -Identify and find examples of surface features caused by destructive processes.

-Erosion (water—rivers and oceans, wind) -Weathering

-Impact of organisms -Earthquake -Volcano

Essential Question: How does the destructive force of erosion change the Earth’s surface?

What is a destructive force?• A destructive force is a process that breaks down the surface

features of the Earth. – Examples are:• Erosion (water-river and oceans and wind)• Weathering • Earthquakes• Volcanoes• Impact of organisms

Erosion• Erosion is the movement of sediments and soil

by wind, water, ice and gravity.

Weathering • Weathering is a term used to describe the process that breaks down rocks at or near the surface of the

Earth.• Weathering causes the surface of the Earth to dissolve, decompose, and break down into pieces. • Anything that causes rock to wear down or break apart is a cause of weathering.

2 types of Weathering Chemical Weathering: Being broken down into new substances chemically (changes what the substance is made of).

• Rocks rusting- This occurs when rocks have exposure to oxygen and water.

• Carbonation- This is when the rock is exposed to carbon dioxide, due to pollution.

• Dissolving- This is when the rock dissolves, due to rain.

Mechanical Weathering- Being broken down so thatthe physical appearance is different, but their chemical

composition remains the same.

• Abrasion- This is scraping by the wind.

• Frost- This is when water freezes in the cracks of the rock and splits it.

• Gravity- This pulls the rocks downward.

A Weathered Monument

Chemical

Rust

Chemical

A Broken Rock

Physical

A Weathered Statue

Chemical

Tree Roots Cracking Cement

Physical

http://studyjams.scholastic.com/studyjams/jams/science/rocks-minerals-landforms/weathering-and-erosion.htm

Resources

• http://www.slideshare.net/calee1182/constructive-and-deconstructive

• http://www.jamestownpublicschools.org/persell/faculty/bshields/Site%202/Earth%20Science.html

• http://alex.state.al.us/lesson_view.php?id=24146