ObjectiveObjective• Students will have an

understanding of how rocks change due to weathering and erosion.

Vocabulary WordsVocabulary Words• weathering – a processes at or near

Earth’s surface that cause rocks and minerals to break down

• erosion – process of removing Earth materials from their original sites through weathering and transport

• rock cycle - a continuous process by which rocks are created, changed from one form to another, destroyed, and then formed again.

How Break DownHow Break Down• As you know rocks can

breaks down into smaller bits.

• There are many ways that a rock may break down. There are broken down by water, wind, and other ways.

• When a rock breaks down, it makes pebbles, sans, silt, and clay.

How Rocks ChangeHow Rocks Change

• Have you ever been outside on a very windy day? Sometimes, small pieces of sand or dirt may hit you legs or face. It hurts!

• A rock begins to break down when the wind blows bits of sand and pebbles on it. This is called weathering a processes that cause rocks and minerals to break down

Changing Rocks Changing Rocks • Another way rocks change

into smaller bits is by moving water.

• You may have help a pebble in your hand that feels smooth. That pebble most likely was smoothed by water in a stream or by ocean waves. This is called weathering a processes that cause rocks and minerals to break down

The Rock Cycle, The Rock Cycle, Weathering and Weathering and

ErosionErosion

• Rocks can be broken down into small pieces.

• Rocks break down into pebbles, pebbles break down into sand. Sand breaks down into silt. Silt breaks down into clay.

• This happens because of weathering.

These are some ways weathering can happen

Water, wind, and other ways Water, wind, and other ways of these, water appears to be the leader in changing the surface.

Weathering by WaterWeathering by Water• Fast moving water causes rocks to hit one

another breaking them into smaller rocks.

Weathering by Frozen WaterWeathering by Frozen Water

• Frost Wedging – cracking of rock by the expansion of water as it freezes in crevices and cracks! Poor rock.

http://www.uwsp.edu/geo/faculty/ozsvath/images/frost%20wedging.jpg

Weathering by Root PenetrationWeathering by Root PenetrationPlant roots have to be strong to survive the elements. Powerful plant roots grow into rock cracks and cause fractures in rocks. This is another form of weathering.

Weathering by the Weathering by the WindWind

• The wind blows and picks up small particles of sand and blasts large rocks with the abrasive particles, cutting and shaping the rock

More Weathering More Weathering • Land is constantly being changed and worn down

by wind, water, and ice.

original level of

the plateau

original level of

the plateau

ErosionErosion• Erosion – a

process of removing Earth materials from their original sites through weathering and transport (movement)

ErosionErosionRemember: Remember: Erosion Erosion

involves involves removalremoval and and transporttransport..

ErosionErosionRainRain,, wind wind, and , and streamsstreams are all are all

parts of erosion.parts of erosion.

If a particle is loosened by weathering, but stays put, its

just weathering. If it starts moving, its Erosion.

Remember this!: You’ll be quizzed soon!

ExperimentExperiment• Observation: The

earth’s crust is not flat everywhere.

• Hypothesis/question: How can sand show weathering and erosion?

• Use the Sand Experiment handout for directions.

Interactive QuizInteractive Quiz• http://www.nps.gov/webrangers/activities/rockpar

k/?id=22

Quiz QuestionsQuiz Questions1. Waves are crashing on a 1. Waves are crashing on a sand beach. sand beach.

1. As the sand is moving 1. As the sand is moving there is definitely erosion; there is definitely erosion; there is also abrasion from there is also abrasion from the sand gains colliding. the sand gains colliding. BothBoth

2. Water expands as it 2. Water expands as it freezes in the cracks of freezes in the cracks of rocks.rocks.

2. This is frost wedging so it2. This is frost wedging so it’’s s weathering. There is no weathering. There is no mention of movement. mention of movement. WeatheringWeathering

Quiz QuestionsQuiz Questions

3. Pebbles move down a 3. Pebbles move down a stream with the current.stream with the current.

3. There is probably some 3. There is probably some weathering, but there is weathering, but there is definitely erosion. definitely erosion. Erosion or Erosion or BothBoth

Quiz QuestionsQuiz Questions

4. a rock slide.4. a rock slide.4. A rock slide could be both 4. A rock slide could be both weathering and erosion. weathering and erosion. because the rocks because the rocks changed slide rock and changed slide rock and may hit other rocks..may hit other rocks..

Quiz QuestionsQuiz Questions

5. A man shovels dirt to 5. A man shovels dirt to plant a tree.plant a tree.

5.Since the man is 5.Since the man is transporting Earth transporting Earth materials, itmaterials, it’’s s Erosion.Erosion.

Quiz QuestionsQuiz Questions

6. A Glacier slowly moves 6. A Glacier slowly moves down a mountain.down a mountain.

6. A glacier moving down a 6. A glacier moving down a mountain would have both mountain would have both weathering and erosion. weathering and erosion. BothBoth

Quiz QuestionsQuiz Questions

7. A tree7. A tree’’s roots grow into s roots grow into the cracks of rocks.the cracks of rocks.

7. A tree7. A tree’’s roots growing s roots growing into cracks of rocks would into cracks of rocks would be weathering. be weathering. WeatheringWeathering

Quiz QuestionsQuiz Questions

8. A major volcano 8. A major volcano erupts.erupts.

8. A major 8. A major volcanic eruption volcanic eruption would involve would involve both weathering both weathering and erosion. and erosion. BothBoth

Quiz QuestionsQuiz Questions

9. A boy takes out the 9. A boy takes out the garbage for his mother.garbage for his mother.

9. Unless the garbage has 9. Unless the garbage has ““Earth MaterialEarth Material”” or dirt in it or dirt in it there is probably no erosion there is probably no erosion or weathering. or weathering. NeitherNeither

Quiz QuestionsQuiz Questions

10. A shovel is left outside 10. A shovel is left outside and begins to rust.and begins to rust.

10. The rusting of a shovel is 10. The rusting of a shovel is oxidation. This is chemical oxidation. This is chemical weathering. weathering. WeatheringWeathering

Quiz QuestionsQuiz Questions

VideoVideo• Rock Cycle Video • https://www.youtube.com/watch?

v=D7WFeh30UpY• Magic School Bus Rocks and

Rolls• https://www.youtube.com/watch?

v=YrC15uySkVE