Erosion, weathering, earthquakes, volcanoes, and the impact of organisms are examples of destructive forces that break down the Earth's surface over time. Erosion is the movement of sediments and soil by forces like wind, water, ice and gravity. Weathering breaks down rocks at or near the Earth's surface through chemical processes like rusting or carbonation, or mechanical processes like abrasion or frost cracking. These destructive forces gradually change the appearance of the Earth's surface features.

1. Destructive
Forces

2. • 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?

3. 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

4. Erosion
• Erosion is the movement of sediments and soil
by wind, water, ice and gravity.

6. 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.

7. 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.

8. Mechanical Weathering- Being broken down so that
the 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.

9. A Weathered Monument
Chemical

10. Rust
Chemical

11. A Broken Rock
Physical

12. A Weathered Statue
Chemical

13. Tree Roots Cracking Cement
Physical

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

17. Resources
• http://www.slideshare.net/calee1182/constru
ctive-and-deconstructive
• http://www.jamestownpublicschools.org/pers
ell/faculty/bshields/Site%202/Earth%20Scienc
e.html
• http://alex.state.al.us/lesson_view.php?id=24
146