2. Weathering The process of breaking down rock by other substances at Earth’s surface Erosion The carrying weathered rock from one location to another Mechanical Weathering Rock is physically broken down Smaller pieces have same composition Chemical Weathering Rock is chemically broken down Smaller pieces have different composition

3. Release of Pressure Topsoil is removed Rock allowed to expand and flake off

4. Freezing and Thawing Water enters crack in rock Water freezes and expands crack in rock

5. Plant Growth Plant roots grow in cracks of rock As roots grow and expand cracks are widened

6. Animal Action Animals (moles, groundhogs, and some insects) dig into ground Soil is then loosened

7. Abrasion Sand and other rock particles are carried by water, wind, and ice Rock is then worn away like sand blasting

9. Chemical Weathering Rock is chemically broken down Smaller pieces have different composition Factors for rate of Chemical Weathering Climate Type of rock Amount of surface area

10. Water Most important cause Dissolves rock Material (Rock) mixes uniformly in water to make a solution

11. Oxygen Oxidation: Oxygen mixes with metal (Iron) Product is rust Rock that has iron in it oxidizes or rust Rust causes rock to become soft and crumble

12. Carbon Dioxide Atmospheric gas Mixes with rainwater and groundwater Water seeps into cracks and pours of rocks Easily weathers limestone and marble

13. Living Organisms Plants that grow on or in rocks produce a weak acid that chemically break down rock Example: Lichens and mosses

14. Acid Rain Burning fossil fuels (oil, coal, and gasoline) Byproduct produces gases (sulfur, carbon, and nitrogen) compounds produced Compounds combine with water vapor in clouds forming acids (carbonic acid) Raindrops fall as acid rain causing rapid chemical weathering

18. How does weathering affect rock? Independent variable: Dependent variable: Things that remain constant: Prediction Materials

19. Procedure Place one sugar cube in each cup Crush one of the sugar cubes Measure out ______ml of water in each graduated cylinder Place water in cup with sugar Time how long sugar takes to dissolve in solution while stirring.

20. Data Table: Graph: Conclusion: What happen to the sugar cubes (use numbers to support) Why did this happen What does the crushed sugar cube represent Was there a possibility for any errors

21. Written response paragraph How does surface area affect the rate the rock is weathered