The Four Agents of Erosion

Finley’s 6th grade Science

Table of contentsHow science works pg 1-2Scientific Method pg 3-10Science engineering and tech. pg 9-12Chapter 1 review pg 13Mineral Earth’s Jewels pg 15-20Section 1 review pg 22Igneous and Sedimentary pg 23-28Metamorphic Rock pg29-32Rock Cycle pg 33-34Chapter 3 Vocabulary Pg 35Do now Foldable Pg 36Section 1 homework pg 37Erosion pg 38-40Do Now 11/8/11 pg 41Glaciers pg 42-46Do now 11/10/11 pg 45

Table of Contents

Wind erosion pg 48

Do now

• Get a piece of colored paperStep 1:Fold the piece of paper into 3rds (like a brochure)Step 2: while the paper is folded up fold it again into

fourthsfold the (brochure like) in half hamburger style

Then open it back up and fold each end to the middle.Step 3: Unfold the whole thing and trace the lines along

the foldsLabel your table

Do Now Foldable pg 36 Erosional Forces Erosion Deposition

Gravity

Glacier

Wind

As we go through the chapter complete the chart , listing specific examples of Erosion and deposition for each erosional force.

Vocabulary on pg 35• Erosion- is a process that wears away surface materials and moves

them from one place to another• Deposition- when agents of erosion drop sediments they are

carrying as they lose energy• Mass Movement- is any type of erosion that happens as gravity

moves materials downslope• Slump- When a mass of material slips down along a curved surface• Creep – occurs when sediments slowly shift their positions down

hill ex: leaning trees• Rockfalls/ Rock Slides- happen when blocks of rocks break loose

and tumble through the air.

Vocabulary pg 35

• Mudflows- occur in areas that have thick layers of loose sediments. Mudflow occur after heavy rain and gravity causes the mass to flow downhill.

Erosions by gravity pg 38

• What wears away Sediments?

• Gravity is the force of attraction that pulls all objects towards Earth.

• Water & wind erode materials only when they have enough energy of motion to do work.

• Ex: air can’t move much sediments on a calm day, but on a strong wind can move dust and even larger particles.

Mass Movement pg 38

• How does gravity aid in mass movement?

• Gravity is constantly pulling object towards Earth. So as long as there is gravity objects will continue to fall and erode in mass movement.

Mass Movement pg 38

• What are the common types of mass movement?

• Slump, creep, rockfalls, rock slides, mudslides, landslides

Mass movements pg 38

• What conditions are favorable for triggering mudflows?

• A normally dry area, with thick layers of dry sediments and vegetation removed by fire or other means, suddenly experiences a heavy rainfall.

Be Prepared to take notes!!!

Consequences of Erosion pg 40

• How do people affect the rate at which erosion occurs?

• People like to build on the side of steep slopes.

In order to do this they must excavate the dirt and vegetation. This speeds up erosion causing additional problems for people.

Consequences of Erosion pg 40

• How can people slow down erosion and make the sloped a safer place to build on?

• One of the best ways to reduce erosion is to plant vegetation and trees with deep roots. This helps to hold the soil in place. People can also build concrete retaining walls.

Do now pg 41

Write down what you think of when you hear the word glacier. Describe what a glacier looks like and how it moves.

Glaciers

Glaciers pg 42

How do glacier form and move?

When snow doesn’t melt it piles up. As it piles up slowly, the weight of the snow gets greater. The snow begins to press the layers into ice. Once there is enough pressure it becomes like plastic. The plasticlike ice starts to move from where it was formed.

Glaciers pg 42

• How does a glacier cause erosion?

• Glaciers erode land and change the surface. They act like a giant bulldozer. They scrape up soil, rocks, and plants and carry them along.

Glaciers pg 42

• What is plucking? • Plucking is the action in which a moving glacier picks up loose pieces of rock.

Glacier pg 42

• What is transporting and scouring?

• A glacier carries huge amounts of sediment and rock as it moves. The action of carrying sediment and rock is called transporting.

• When moving glaciers scour the bedrock, they leave marks on it.

Glaciers pg 44

• What types of marks do glaciers leave?

• What is the difference between Striations and grooves.

• Glaciers leave Striations and grooves.

• Striations are shallow marks.

• Grooves are long, deep, side-by-side scars.

Grooves & Striation

Grooves Striation

Glaciers pg 44

• What is till? Till is the mix of different sized sediments that are deposited from a retreating glacier.

Glaciers pg 44

• What are moraine deposits?

• Rocks and soil are moved to the end of glacier. As a result, a big ridge of soil and rocks pile up. This deposit is called a moraine.

Glaciers pg 46

• What is an outwash?

• What are eskers?

An outwash is the material deposited by the water from a melting glacier.

An esker is a meltwater stream inside the glaciers ice.

Eskers

Do now 11/10/11 pg 45

Identify- name two kinds of marks that glaciers leave in a rock?

Think about a windy day when dust or sand was blown in your face. Write about how it felt.

Left over Esker from a glacier

Glacier pg 46

What are the two types of glaciers?

What is the difference between Continental and valley glaciers?

The two types of glaciers are continental glaciers and valley glaciers.

Continental glaciers are wide, thick sheet of ice and snow. They cover huge areas of land.

Valley glaciers are found in high mountain ranges.

Glacier’s pg 46

• Identify some states that were once covered by a glacier.

Glaciers pg 46

• What are the signs that valley glaciers existed?

1. Look for grooves in the rock.

2. Look for signs of plucking3. Bowl shaped basins called

cirques.4. If the mountain was

eroded from many directions it can form a horn.

5. An arete which is a ridge where two glaciers have eroded side-by-side

Valley Glaciers

Wind Erosion pg 48

What is wind erosion? Erosion is the process that wears away surface materials and moves them from one place to another.

When air moves, it picks up tiny bits of loose material. Air is different then Gravity or glaciers in that it cannot pick up heavy sediments.

Wind pg 48

• How does deflation erode the land?

• Deflation is erosion that occurs when wind removes small sediments, such as silt and sand, leaving behind large sediments.

Wind Erosion pg 48

• How does abrasion erode the land?

Just as a sandblaster sprays a mix of sand and water to clean and polish materials. Abrasion scrapes and wears away rock pieces leaving them pitted, polished, and worn down.

Wind erosion pg 48

• Where so deflation and abrasion occur most often?

Deflation and abrasion occur most at beaches, deserts, and plowed fields.

Wind erosion pg 50

• What are sandstorms? When strong winds blow in a sandy desert, the sand grains raise into the air. The blowing sand forms a cloud just above the ground.

Wind pg 50

• What causes a dust storm?

Dust storms are clouds of fine particles of soil blown by wind. Dust storms can cover hundreds of kilometers.

Dust Bowl

Reducing wind erosion pg 50

How do we reduce wind erosion?

People plant vegetation to stop wind erosion. These are called wind breaks. As wind hits the trees it slows down the wind.

Deposition of Wind pg 50

• What does the deposited sediments from wind form?

• Over time, some of the sediments develop into landforms such as dunes and loess.

Wind Deposition

Dune Loess

Wind Deposition pg 52

What is a loess? Loess are wind deposits of fine grained sediments. The sediments pack together creating a thick, un-layered, yellow and brown in color.

Wind deposition pg 52

What are dunes?

How do dunes move?

Dunes happen when wind blows sediments against an obstacle such as a rock or vegetation.

A sand dune has two sides. The side facing the slope which has a gentle slope, and the side away from the wind which is steeper. The dunes move in the direction away from the wind.

Wind deposition pg 52

Dune shapesBarchan dune- crescent shaped

Transverse Dune-Dunes are perpendicular to the wind direction