By the end of the lesson, I will beable to…Describe the processes thatwear down and build up Earth’ssurface.Identify the force that pulls rockand soil down slopes.
I. Wearing Down and Building UpA.Erosionis the process by which naturalforces move weathered rock and soilfrom one place to another.B.The material moved by erosion issediment.C.Depositionoccurs where the agents oferosion lay down sediment.D.Weathering, erosion, and deposition acttogether in a cycle that wears down andbuilds up Earth’s surface.
II. Mass MovementA.Gravityis the force that moves rock andother materials downhill.B.Gravity, running water, glaciers, waves,and wind cause erosion.C.Gravity causesmass movement, anyone of several processes that movesediment downhill.D.The different types of mass movementinclude landslides, mudslides, slump,and creep.
II. Mechanical WeatheringD.The most destructive kind of massmovements is a landslide, which occurswhen rock and soil slide quickly down asteep slope.
II. Mechanical WeatheringE.A mudflow is the rapid downhillmovement of a mixture of water, rock,and soil.F.Mudflows often occur after heavy rainsin a normally dry area.
II. Mechanical WeatheringG.In slump, a mass of rock and soilsuddenly slips down a slope.H.The material in slump moves down inone large mass.
II. Mechanical WeatheringI.Creep is the very slow downhillmovement of rock and soil, evenoccurring on gentle slopes.J.Creep often results from the freezingand thawing of water in cracked layersof rock beneath the soil.
In-Class Review1.Explain the difference between erosionand deposition.2.What forces cause erosion?3.What are four types of massmovement?4.Why would a landslide be more likely ona steep mountain than on a gentlysloping hill?
AssignmentRead pages 252-261
Water ErosionLesson 8-2
By the end of the lesson, I will beable to…Explain how water erosion is mainlyresponsible for shaping Earth’s landsurface.Describe some of the land featuresformed by water erosion, includinggroundwater erosion.Describe land features formed whenrivers and streams deposit sediment.Describe the features of a riversystem.
I. Runoff and ErosionA.Moving water is the major agent of the erosionthat has shaped Earth’s land surface.B.Runoffis all the remaining water that movesover Earth’s surface.C.As runoff travels, it forms tiny grooves in thesoil calledrills.D.Agullyis a largegroove, or channel, inthe soil that carriesrunoff after arainstorm.
I. Runoff and ErosionE.Astreamis a channel along which water iscontinually flowing down a slope.F.As streams flow together, they form larger andlarger bodies of flowing water.