Activity 29 Weathering, Erosion and Deposition

Challenge . . . What happens when soil and rocks are moved from one place to another? Key vocabulary Earth process Destructive process Constructive process Weathering Erosion Deposition

Vocabulary Definitions: Earth Process: Dynamic actions that occur both on the earth’s surface and inside the earth. Destructive Process: destroys land Constructive Process: builds land Weathering: process which breaks down rocks Erosion: A type of weathering in which surface soil and rock are worn away through the action of glaciers, water, and wind. Deposition: The act of depositing eroded sediment

GETTING STARTED What happens to all of the bits of rock and soil (i.e., sediment) that are eroded by flowing water? The sediment is TRANSPORTED. It gets carried into lakes, oceans and other bodies of water. It may also end up further down the hill or river. The result of any earth process is CHANGE. This change may be short- or long-term; gradual or drastic.

Review TERMS Match the Earth process with the proper definition. Erosion A. Rock is broken down into sediment Deposition B. Sediment settles or is left behind Weathering C. Sediment is transported by wind, water, ice or gravity Erosion is sediment being transported by wind, water, ice or gravity. Deposition is sediment settling or being left behind. Weathering is rock being broken down into sediment (i.e., smaller pieces).

Apply TERMS Order the Earth processes from first to last. Erosion Deposition Weathering FIRST Weathering SECOND Erosion LAST Deposition

PROCEdure Read the introduction on page 22. Tape the “Three-Level Reading Guide: Weathering, Erosion and Deposition” into your journal. Preview the questions on this sheet. Read pages 23-26. Complete the “Three Level Reading Guide” as you read.

“FOLLOW-UP” What are some positive and negative effects of erosion? POSITIVE . . . J Removes sediment from useful landforms (e.g., lakes, valleys) NEGATIVE . . . L Removes topsoil Damages property Injures or kills people (e.g., landslides)

“FOLLOW-UP” What are some positive and negative effects of deposition? POSITIVE . . . J Creates fertile farmland in valleys and floodplains Creates deltas which provide habitat for diverse wildlife NEGATIVE . . . L Sediment fills in lakes and resevoirs Damages property during floods

ANALysis questions (page 27) Answer Questions #2, 3 and #5 (A and B). All answers should be written in complete sentences. All questions should be answered independently.

ANALYSIS ANSWERS 2. Erosion picks up particles of rock and soil (i.e., sediment). These particles are eventually deposited somewhere when the flowing water (or wind) slows down. An example is when the sediment eroded by a river is deposited at the mouth of the river, creating a delta.

3. The flowing water slowly removes the particles of rock through the process of weathering. The flowing water then carries the rock particles away down river via the process of erosion. The walls are so steep and high because rock does not slump or collapse as easily as softer material (e.g. sand)

Analysis answers (#5) Delta Marsh: could wash away the soil of the marsh and make it less stable. Also, could result in unwanted earth material in people’s yards. Green Hill: could cause the hillside to collapse and weaken buildings built above. Sediment could also end up on the houses below. Seaside Cliff: could weaken or wash away the cliff