Weathering Weathering The process of breaking down rock

Weathering

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

Mechanical Weathering types � Release of Pressure �Topsoil is removed �Rock allowed to expand flake off

Mechanical Weathering types � Freezing and Thawing �Water enters crack in rock �Water freezes and expands crack in rock

Mechanical Weathering types � Plant Growth �Plant roots grow in cracks of rock �As roots grow and expand cracks are widened

Mechanical Weathering types � Animal Action �Animals (moles, groundhogs, and some insects) dig into ground �Soil is then loosened

Mechanical Weathering types � Abrasion �Sand other rock particles are carried by water, wind, and ice �Rock is then worn away like sand blasting

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

Chemical Weathering types �Water � Most important cause � Dissolves rock � Material (Rock) mixes uniformly in water to make a solution

Chemical Weathering types �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

Chemical Weathering types �Carbon Dioxide � Atmospheric gas � Mixes with rainwater and groundwater � Water seeps into cracks and pours of rocks � Easily weathers limestone and marble

Chemical Weathering types �Living Organisms � Plants that grow on or in rocks produce a weak acid that chemically break down rock �Example: Lichens and mosses

Chemical Weathering types �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

Chemical Weathering Acid Rain

Chemical Weathering Acid Rain

Chemical Weathering Acid Rain

Sugar Cube Lab �How does weathering affect rock? �Independent variable: �Dependent variable: �Things that remain constant: �Prediction �Materials

Sugar Cube Lab �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.

Sugar Cube Lab � 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

Sugar Cube Lab �Written response paragraph � How does surface area affect the rate the rock is weathered