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SLOW Processes that Shape the Earth PART 1. WEATHERING

SLOW Processes that Shape the Earth PART 1. WEATHERING. Mrs. Wright Hugh B. Bain Middle School Cranston, RI. Earth - developed over long periods of time through continual change processes. STUDENTS: Evaluate slow processes of 1) weathering 2) erosion and 3) mountain building.

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SLOW Processes that Shape the Earth PART 1. WEATHERING

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  1. SLOW Processes that Shape the EarthPART 1. WEATHERING Mrs. Wright Hugh B. Bain Middle School Cranston, RI

  2. Earth - developed over long periods of time through continual change processes. STUDENTS: • Evaluate slow processes of 1) weathering 2) erosion and 3) mountain building. The following slides are on weathering. • Determine how the earth has changed and will continue to change over time.

  3. Weathering – What is it?Mechanical (physical) and chemical processes that break down rock at Earth’s surface Mechanical Weathering Chemical Weathering rock physically broken into smaller pieces rock breaks down from exposure to water and atmospheric gases (CO2, O2, and H2O vapor). uk‑stonehenge.jpg

  4. Mechanical Weathering What is it? Type of weathering where rock is physically broken into smaller pieces

  5. Causes of Mechanical Weathering Freezing & Thawing Release of Pressure Plant Growth Action of Animals Abrasion

  6. Freezing & Thawing Ice wedging Water freezes in crack in rock Expands and makes crack bigger Process also causes cracks in sidewalks & potholes in streets http://mail.colonial.net/~hkaiter/science%20images/frostwedging.gif

  7. Freezing & Thawing http://www.google.com/imgres?imgurl=http://upload.wikimedia.org/wikipedia/commons/e/eb/Pothole_Small.jpg&imgrefurl http://images.suite101.com/88099_brokenrk.jpg

  8. Release of Pressure Erosion removes material from rock Pressure on rock is reduced Causes outside of rock to flake off like layers of onion http://www.google.com/imgres?imgurl=http://environment11.pbworks.com/f/1273571046/exfoliation1.jpg&imgrefurl

  9. Plant Growth Roots enter cracks in rocks Grow Force cracks farther apart or pry them apart http://www.google.com/imgres?imgurl=http://video.ecb.org/badger/download/vlc/images/VLC161_Roots_breaking_rocks.jpg&imgrefurl

  10. Plant Growth http://www.google.com/imgres?imgurl=http://www.wkmctv.com/geo_images/root_wedging.jpg&imgrefurl

  11. Action of Animals Burrowing animals loosen and break apart rocks in soil http://www.google.com/imgres?imgurl beeholes.jpg

  12. Water vole burrows Action of Animals 090629081133‑large.jpg brook-meadow.hampshire.org.uk Burrowing frog Water Vole.jpg 567 × 438 - Water Vole dungevalley.co.uk

  13. Action of Animals http://timenewsfeed.files.wordpress.com/2010/11/106302684.jpg http://dirttime.ws/Photos/IM002689.jpg

  14. Abrasion What is it? grinding away of rock by rock particles carried by water, ice, wind or gravity riverrocks.jpg

  15. Abrasion Sand & rock particles carried by wind & water, wear away exposed rock like sandpaper on wood. image002.jpg 569 × 358 - wave action (mechanical weathering) photo courtesy of R. Weller skywalker.cochise.edu

  16. Chemical Weathering What is it? Type of weathering where rock breaks down from exposure to water and atmospheric gases (CO2, O2, and H2O vapor).

  17. Causes of Chemical Weathering Action of Water Oxygen (Oxidation) Carbon dioxide (CO2) Living Organisms Acid Rain

  18. Action of Water Most important cause of chemical weathering Dissolves rock 3572473_f520.jpg 520 × 390 - ... formed by chemical weathering. Water dissolves the calcites in the rock ... hubpages.com

  19. Action of Water 278.Jpg form where water collects and accentuates rates of chemical weathering uregina.ca

  20. Oxygen (Oxidation) What is it? Iron (Fe), or other metal, combines with oxygen in the presence of water If metal is Fe, causes rust Rock containing iron also rusts then crumbles apart Rusting causes Red/brown color jimeno2.glogster.com

  21. Carbon dioxide (CO2) chemical‑weathering‑process‑3.1‑800X800.jpg Rain water and carbon dioxide create carbonic acid. This mild acid interacts ... ehow.co.uk CO2 dissolves in rainwater Forms carbonic acid that seeps into soil Easily weathers rocks like limestone & marble

  22. Carbon dioxide (CO2) • Water seeped into cracks in limestone & cracks enlarged gradually • Rainwater became acidic as it dissolved carbon dioxide from the air and soil • Dissolved away rock to form cave system • Water dripping from cracks in cave roof, lost dissolved CO2 & depositsCaCO3 • Formed stalactites, stalagmites or smooth flowstone Cheddar caves xtrawide.jpg ... loses some of its dissolved carbon dioxide and deposits some of its ... geolsoc.org.uk

  23. Living Organisms Lichens (plant-like organism) & roots of plants produce weak acids Slowly dissolve rock around roots trans_s_lichensndstn.jpg Stone colonized by lichens, which bit by bit dissolve the rock into .morning-earth.org

  24. Acid Rain Coal, oil, gas burned past 150yrs S, C & N compounds put in air React chemically with water vapor in clouds Form acids Acids mix with raindrops & fall as acid rain Causes very rapid chemical weathering _Acid_rain_damaged_gargoyle_‑.jpg Silverchair — Acid Rain lyrics lyricsdog.eu

  25. Rate of Weathering What is it? How fast weathering occurs

  26. Most important factors determining how fast weathering occurs: Type of Rock Climate

  27. Type of Rock Minerals that make up rock determine how fast it weathers If minerals dissolve slowly in water, rock weathers slowly. If minerals dissolve quickly in water, rock weathers quickly. Rocks.jpg edweb.tusd.k12.az.us

  28. Permeability • What is permeability? Material is full of tiny connected air spaces that allow water to seep through it. • Some permeable rock may weather more quickly • Weathers chemically at faster rate because water easily seeps into it, dissolves it & removes material

  29. Climate climate – refers to average weather conditions in area Chemical and mechanical weathering occur faster in wet climates Rainfall provides water needed for chemical changes & physical changes (freezing and thawing) High temperatures - Chemical reactions occur more quickly 470px‑ClimateMap_World.png _

  30. Rate of Weathering 278.Jpg water collects and accentuates rates of chemical weathering uregina.ca

  31. Looking at the SLOW process of weathering, how has the earth changed over time? Give at least three examples and explain each. Is the earth still changing through weathering? How do you know? Give at least three examples and explain.

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