Earth and Life Science SHS 7.1 Weathering.pptx

Earth and Life Science SHS 7.1 Weathering.pptx

1. Lesson 7.1 Weathering

2. differentiate mechanical weathering and chemical weathering; and 1 At the end of the lesson, you should be able to: 2 describe how rocks undergo weathering; enumerate the factors that contribute to weathering. 3

3. Weathering is the process of breaking down rocks present at Earth’s surface. Weathering can happens in the presence of the action of rainwater, variable extreme temperature, and different biological activities. Weathering

4. Mechanical weathering is a process wherein rocks are broken down into smaller pieces without changing their chemical composition due to several factors like fluctuating temperatures and pressure, and biological activity. Mechanical Weathering Rocks by the sea change shape due to the force of water during high tide.

5. Frost wedging is a process that involves repeated cycles of freezing and thawing of ice. It happens when there is sufficient moisture; pre-existing cracks; and when temperatures frequently rise and fall Types of Mechanical Weathering Weathering of rocks through frost wedging

6. Salt crystal growth is a process that happens when seawater penetrates crevices in rocks which are found mostly in rocky shorelines and arid regions. Salt crystals expand when subjected to an increase in temperature that causes the widening of cracks. Types of Mechanical Weathering Rock weathering in beaches

7. Biological activity is the action of organisms including plants and animals reduces the size of rocks and minerals which make rocks more susceptible to chemical weathering. Types of Mechanical Weathering W eathering by roots of plants

8. Unloading happens through erosion or uplift, thick layers of sediments overlying deeply buried in rocks are removed. This process is termed unloading. Types of Mechanical Weathering Unloading of rocks

9. Chemical weathering is a process wherein rock materials are changed into other substances that have different physical and chemical compositions. Chemical Weathering Chemical weathering

10. Dissolution is a process wherein a solid (i.e., halite) dissolves in a liquid (i.e., water). Hydrolysis is a process where water reacts with a mineral to form a new mineral. Oxidation is a where chemical combination of oxygen with a mineral to form an entirely different mineral in which at least one of the elements has a higher ionic charge. Types of Chemical Weathering

11. Climate mainly includes the amount of moisture in the air and temperature where weathering takes place. The higher the elevation of an area , the more susceptible it is to weathering since it is more exposed to environmental factors. Factors Affecting Weathering of Rocks

12. Weathering rapidly occurs when there is a large surface area exposed to surface processes. When a block is broken into smaller pieces, it has a larger total surface area which makes it more susceptible to weathering. Factors Affecting Weathering of Rocks A block that is broken into smaller pieces has a higher total surface area.

13. Goldich stability series illustrates the relative stability or weathering rate of numerous minerals. This series is roughly the inverse order of original crystallization for minerals found in the Bowen’s reaction series. Factors Affecting Weathering of Rocks Goldich stability series

14. Weathering is the breaking down of rocks either mechanically or chemically. 1 Weathering of rocks is caused by numerous factors such as climate, surface area and topographic relief, and rock composition. 2 3 Weathering can either be in the form of chemical or mechanical weathering.

15. Write true if the statement is correct, and false if the statement is incorrect. Frost wedging is an example of mechanical weathering. Karst topography is a landscape formed by the dissolution of carbonate rocks. Weathering slowly occurs when there is a large surface area exposed to surface processes. Hydroglyphics is a process wherein water reacts with a mineral to form a new mineral. Dissolution refers to a process where erosion removes the thick layers of sediments overlying deeply buried rocks.

16. Which type of weathering would produce more sediments, mechanical weathering or chemical weathering?

17. Amethyst Galleries Inc. “Mineral Gallery” Accessed April 5, 2018. http://www.galleries.com/default.htm Coenraads, Robert R. 2005. Rocks & Fossils: A Visual Guide. Australia: Weldon Owen Inc. Tarbuck, Edward J. and Frederick J. Lutgens. 2012. Earth Science, 13th Edition. New Jersey: Pearson Prentice Hall. Thompson, Graham R. and Jonathan Turk. 1997. Introduction to Physical Geology. United States: Brooks Cole Publishing. Williams, Linda. 2004. Earth Science Demystified. United States: The McGraw -Hill Companies, Inc.

18. This file, Puerto Princesa Underground River by Mike Gonzalez is licensed under CC-BY-SA 3.0 via Wikimedia Commons .