Transcript File - Ms. D. Science CGPA

Erosion and Deposition
Table of Contents
Water Erosion
Online Activity
Ms. De Los Rios
6th Grade
Vocabulary Ch. 4.1
1. Runoff- Water that flows over the ground surface rather than soaking
into the ground.
2.
Rills- A tiny groove in soil made by flowing water.
3. Gully- A large channel in soil that carries runoff after a rainstorm.
4. Stream- A channel through which water is continually flowing downhill.
5. Tributary- A stream or river that flows into a larger river.
6. Flood plain- a flat valley through which a river flows through. ‘
7. Meander- A looplike bend in the course of a river.
8. oxbow lake- A meander cut off from a river.
Vocabulary 4.1
9. Delta- A landform made of sediment that is deposited where a river
flows into an ocean or lake.
9. Alluvial fan- a wide, sloping deposit of sediment formed where a
stream leaves a mountain range.
10. Groundwater- Water that fills the cracks and spaces in underground
soil and rock layers.
11. Stalactite- An icicle-like structure that hangs from the ceiling of a
cavern.
12. Stalagmite- a column-like form that grows upward from the floor of a
cavern.
Karst Topography- Karst Topography (K.T.) landscape in rainy regions
where there is limestone near the surface and has caverns, sinkholes,
and deep valleys. (sinkholes are more likely found in regions with K.T.)
Pg. 114-115
What process do you know that breaks up rocks?
Weathering
What are the agents or natural forces that weather rocks?
Water, living things, oxygen, carbon dioxide, changing temperature
What forces on Earth have you observed picking up or moving
rocks, sand, or mud?
Floodwaters, gravity, strong winds, and people
Pg. 116
Mass- is an amount of matter that has and indefinite size and shape.
Force- is the push or pull exerted on an object.
Cycle- is a sequence of events that repeats over and over again.
Give samples of various types of cycles
•
•
•
Water Agent(force that causes change) of
Erosion
•How can water be an agent of erosion?
By flowing over Earth’s surface.
•In what ways does this water flow?
As a sheet, in rills, in gullies, and in streams.
•What factors determine the amount of runoff in an area?
Amount of rain, vegetation, type of soil, shape of the land, how
the land is used.
Factors and Processes that Shape Earth’s
Surface
•How do people shape Earth’s surface?
They dig sediment and rocks from one place and dump them at
another place.
Water also picks up sediment at one place and deposits it at
another.
Which factor/process do you think moves more sediment,
people or water?
Water moves much more sediment than people.
How Does Moving Water Causes Erosion?
Moving water is the major agent of the
erosion that has shaped Earth’s land
surface.
• As water moves over the land, it carries
particles with it.
This moving water is called runoff.
The amount of runoff in an area depends
on five main factors:
1. the amount of rain an area gets,
2. the area’s vegetation
3. the type of soil
4. the shape of the land
5. how people use the land
Water Erosion pg. 119
Factors Affecting Runoff
1. What are the five main
factors affecting runoff,
and what are some
examples?
2. Using a specific
location, such as a
local park, identify an
example for each
factor.
3. Explain to a partner
what the runoff would
be like at your location.
Stream Formation pg. 120
As runoff travels downhill under gravity, it forms tiny grooves in
the soil called rills.
When many rills flow into one another, they grow large, forming a
gully. A gully is a large groove, or channel in the soil that
carries runoff after a rainstorm.
Gullies join together to form a larger channel called a stream. A
stream is a channel along which water is continually flowing
down a slope.
A large stream is often called a river.
A stream or river that flows into a larger river called a tributary.
As water moves across the land it forms:
pg. 120
Rills
Gullies
Streams
River
Tributary
Key Concepts
How can water move soil and sediment?
By flowing over Earth’s surface
In what ways does the water flow?
Sheet, in rills, gullies, and in streams.
Water Erosion
pg. 120
Stream Formation
Which arrows indicate the
direction of sheet
erosion? Where are rills
and gullies in the picture?
Streams and rivers?
Tributaries?
Land Features formed by Water Erosion
pg. 122
As water moves it forms through erosion:
1.
2.
3.
4.
5.
V__________
W__________
F_______ P_________
M__________
O_______ L_________
What Land Features Are Formed by Water
Erosion? Pg. 122
Through erosion, a river creates
valleys, waterfalls, flood plains,
meanders, and oxbow lakes.
• The flat, wide area of land along a river
is a flood plain.
•
A meander is a looplike bend in the
course of a river.
• An oxbow lake is a meander that has
been cut off from the river.
• Waterfalls form where a river meets
an area of rock that is very hard and
erodes slowly.
Water Erosion
Waterfalls
Where do you think the layers
of hard and soft rock are
located?
Water Erosion Fig. 5 pg. 123
Oxbow Lakes
What happens in
step 4 of this
diagram to form
an oxbow lake?
Land Features formed by Water Deposition
pg. 124
As water moves it carries sediment and deposits it forming:
1.
2.
What Land Features Are Formed by Deposition? Pg. 124
Deposition creates landforms such
as alluvial fans and deltas.
Sediment deposited where a river flows
into an ocean or lake builds up a
landform called a delta.
An alluvial fan is a wide, sloping deposit
of sediment formed where a stream
leaves a mountain range. It is shaped
like a fan.
Water Erosion pg. 124
Water Deposition
Deposition creates landforms such as the Mississippi River
delta.
Water Erosion Fig. 7 pg. 125
Rolling Through the Hills
Identify the two missing features on the image.
Groundwater Erosion pg. 126
Groundwater is the term geologists use for underground water.
. Groundwater can cause erosion via
chemical weathering.
• Rain water is acidic
• Atmosphere =
water+ carbon dioxide= carbonic acidic (weak acid)
• Carbonic acid breaks down limestone- the limestone is carried
away in the water. Gradually, little by little, this process hollows
out the rock forming caves/caverns.
Cave Formations pg. 126
Did you know that Carbonic acid on limestone can also result in
deposition!!
• A deposit that hangs like an icicle from the roof of a cave is known
as a
stalactite.
Slow dripping builds up a cone-shaped stalagmite
floor.
from the cave
Karst topography is a type of landscape in rainy regions where there
is limestone near the surface and characterized by caverns,
sinkholes, and deep valleys.
The Schellenberg ice cave pg, 126
The Schellenberg ice cave in
Germany is a limestone cave
with ice formations. Cold air is
trapped in the lower areas of the
cave so the temperature stays
near freezing. This keeps the ice
formations from melting.
Water Erosion Fig. 6 pg. 126
Groundwater Erosion and Deposition
How do the processes of Erosion and Deposition form caves?
Water Erosion Apply it! Pg. 127
Karst Topography
Why do you think karst
topography occurs in these
areas?
1. Name three states in
which you can find Karst
topography?
____________________
____________________
____________________
2. Why do you think Karst
topography occurs in
these areas?
____________________
____________________
____________________