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January 18, 2013Q-2 Pg.

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January 18, 2013 Q-2 Pg. Daily Goal: We will be able to articulate the difference between erosion and deposition. We will demonstrate how geographical features ... – PowerPoint PPT presentation

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Title: January 18, 2013Q-2 Pg.


1
January 18, 2013 Q-2 Pg.
  • Daily Goal We will be able to articulate the
    difference between erosion and deposition. We
    will demonstrate how geographical features
    influence deposition.
  • Homework Study for Thursday and Fridays mastery
    quiz! Enjoy your long weekend!
  • Science Starter
  • What is deposition?
  • What factors might determine why sediment builds
    up in one area and not in another?
  • What is the difference between weathering,
    erosion, and deposition?

2
Review Questions
  • Weve been talking about weathering, erosion and
    the impact of human actions.
  • Identify as mechanical or chemical weathering
  • Acid rain slowly wears down a statue.
  • A rock rolls down a hill and cracks in half.
  • A tree root grows into a rock, breaking it into
    small pieces.
  • Oxygen in the atmosphere reacts with iron in
    rocks creating a rusty color.

3
Major types of erosion
  1. Stream bank
  2. Topsoil
  3. Coastal

4
What words do we need to know to be able to speak
like scholars about this subject?
  • Write this in your glossary
  • Erosion the process in which sediment is picked
    up and moved from one place to another
  • Deposition when sediment that is being
    transported gets dropped in a location

5
  • I. Stream bank erosion is the movement of
    sediment from the sides of streams or rivers.
  • Stream bank erosion is caused by running water
    and burrowing animals (like nutria).

6
What are ways we could stop stream bank
erosion?Does it seem like a natural type of
erosion?So, humans dont do ALL the damage.
7
Methods to control stream bank erosion
The roots of the plants hold soil back!
1. Planting plants on the edge of a stream or
river.
2. Placing concrete mats, netting or logs on the
sides of a stream.
Manmade nets and mats also hold back and keep
it from washing away!
8
III. Coastal Erosion is the movement of soil and
sediment from coastal areas.Land Ocean
meeting the coast
9
What causes coastal erosion--humans or nature??
All the grass is gone!!
10
BOTH!
  • Erosion caused
  • by Nature
  • 1. Subsidence when land sinks as sediments
    compact
  • 2. Hurricanes and storms
  • 3. Sea level rise
  • Erosion caused
  • by Humans
  • 1. Building levees
  • 2. Oil field canals
  • 3. Oil gas production causes increased
    subsidence

11
II. Topsoil Erosion is the wearing away of the
top layer of soil due to water runoff or
rainfall, wind and gravity.
12
What exactly is topsoil??
  • Topsoil is the upper, outermost layer of soil.
  • Usually 2-8 inches deep.
  • It contains most of soils living matter and
    nutrients.
  • This is where plant roots grow!

13
Methods to prevent topsoil erosion
  1. No-till farming soil is not tilled (stirred) and
    dead plant material builds up and covers the
    surface of the land
  2. Contour plowing farmers plow in curved rows,
    parallel to the curve of the land
  3. Terracing farmers cut steps into steep hillsides
  4. Cover-crops Crop Rotation certain crops are
    good for restoring the natural balance of
    nutrients in the soil and preventing erosion

14
Human impact It might seem like fun, but when
youre done, youve destroyed the earth a little
bit
Climbing and surfing on sand dunes in Namibia.
4-wheeler tracks
15
WHAT DO YOU THINK?Why is it important to
prevent erosion of topsoil?Why do farmers
work so hard to make sure their soil is good?
16
We know the earth has been here for a long time
and things happen slowly.
  • It takes approximately 100 years for one inch of
    topsoil to be created through the weathering and
    erosion of rocks.
  • There are 25 billion tons of topsoil lost each
    year due to erosion!
  • We need topsoil to grow crops
  • so we have food to eat.

17
Lets try it out!
  • You will need
  • 1 clear box filled ¼ of the way full with sand
  • 1 straw
  • 2 rocks

18
What is soil?What is it made of?Whats in it?
19
Soil is a mixture of pieces of rock, organic
matter, air and water.
20
Rock fragments (pieces) can be
  • Sand
  • Silt
  • Clay

21
Humus isthe organic part of soil decaying plant
and animal matter, such as leaves, roots and dead
animals.
22
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23
Soil is made in layers, which are called
horizons.
  • The layers of soil are made of different types of
    sediment and nutrients.

24
There are 3 horizons (A, B, C) that form a soil
profile.
SOIL HORIZON LAYER ORGANIC MATTER COLOR NUTRIENTS
A Horizon Topsoil High Darkest High
B Horizon Subsoil Low Lighter Low
C Horizon Weathered Bedrock Low Lightest Low
Fill in the whole chart!
25
The layers!
  • A Horizon
  • B Horizon
  • C Horizon
  • Bed rock

26
WHAT IS THAT???
  • In Louisiana there is NO C Horizon. So, there is
    NO bedrock layer under the soil.

27
What is a possible effect? Meaning, what
happens because there is not bedrock under the
soil in Louisiana?
28
Exit Slip
A Horizon B Horizon C Horizon
  • Which layer of soil is most important for growing
    crops?
  • Which layer of soil contains humus?
  • Which layer of soil is made up of partially
    broken bedrock?
  • What is humus?
  • Parent rock c. Bedrock
  • Plants and animals d. Horizon B
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