River Erosion Gizmo
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School
Howard Community College *
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Course
101
Subject
Geography
Date
Dec 6, 2023
Type
Pages
6
Uploaded by AgentFlagDog4
Student Exploration: River Erosion
Directions: Follow the instructions to go through the simulation. Respond to the questions and
prompts in the orange boxes.
Gizmo Warm-up
If you stand by the bank of a river, it may seem that very little is
happening. But over thousands and even millions of years, rivers
can have a profound effect on the landscape. In the
River Erosion
Gizmo, you will see how rivers move materials and how they
affect landscapes.
To begin, check that
Mountain stream
and
Short-term erosion
are selected. The Gizmo shows a typical stream that is moving
through a hilly area.
1.
The two movie cameras (
) allow you to observe
different parts of the stream up close. Click on the
left movie camera. What do you see?
I see a streambed which is rocky. There
are small substances that are being
carried by the stream current.
2.
Sediments
are small rock fragments such as sand
or pebbles. What evidence do you see that
sediments are being transported?
The sediments are moving from left to
right.
3.
Now select the right movie camera to see the bank
of the mountain stream. What is happening to
sediments on the bank?
The sediments are falling into the stream.
Activity A:
Mountain
streams
Get the Gizmo ready:
●
Check that
Mountain stream
and
Short-term erosion
are selected.
●
If necessary, click outside the circle to close the
zoomed-in view.
Introduction
:
Erosion
occurs when sediments and other materials are moved from one place to another.
Along with
weathering
, which is the breakdown of large rocks into smaller sediments, erosion can have a
profound impact on the landscape.
Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved
1.
Label: First, get to know some of the different parts of a
mountain stream. Turn on
Show labels
. Fill in the word
that goes with each description.
A small stream that flows into a
larger stream:
Waterfall
A place along a stream where
water drops straight down:
Tributary
A letter that describes the shape
of a typical mountain valley:
V
The side of a stream:
Streambank
The bottom of a stream:
Streambed
2.
Observe: Turn off
Show labels
. Next to “Release barrel,” click
Play
(
). Observe how fast the barrel
moves as it floats down the stream.
What happens when the barrel goes over the
waterfall
?
It goes over first, then flows along with the stream of the river. The speed of the barrel
increase from the flag checkpoint.
3.
Observe: Turn off
Show data
. Next to
River flow
, select
Flood
. Look at the landscape, and then click on
the movie cameras to see zoomed-in views. Describe what you notice below.
I notice that the color of the water is different. (It is in a brownish color); the water seems to
be flowing much slower and water level is higher based on the visual.
Activity B:
Meandering rivers
Get the Gizmo ready:
●
Select
Meandering river
.
●
Select
Short-term erosion
,
Low
vegetation, and
Normal
river flow. Turn off
Show data
.
Introduction
:
Meandering rivers
are found in flatter areas. Unlike the V-shaped mountain valleys, the valleys
of meandering rivers have wide, flat bottoms called
floodplains
.
Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved
1.
Label: Turn on
Show labels
. Fill in the word that goes
with each description.
A large S-shaped bend in a river:
meander
A flat area next to the river
floodpain
A steep stream bank on the
outside of a bend in the river:
cutbank
A gently sloping deposit of
sediments on the inside of a
bend in the river:
pointbar
2.
Observe: Turn off
Show labels
. Click
Play
to release the barrel. Observe the path of the barrel as it floats
down the river. (The flags are 100 meters apart.)
A.
Turn on
Show path
. Did the barrel stay in the center of the
river or go from side to side?
no, the barrel did not go side
to side.
B.
As the barrel went around each meander, did it stay closer
to the
point bars
or the
cutbanks
?
it stayed closer to the
cutbanks.
In a meandering river, the water flows faster on the outside of a
meander
, near the cutbank, and moves
more slowly near the point bar on the inside of the meander. The current carries the barrel toward the
cutbanks and away from the point bars.
3.
Compare: Click
Reset
. Turn on
Show data
. List the slope, speed, discharge, and transported sediments of
the meandering river. Then select
Mountain stream
and fill in the remainder of the table. Change back to
the
Meandering river
and compare the values.
Meandering river
Mountain stream
Slope
1.0 m/km
22 m/km
Speed
0.8 m/km
1.1 m/km
Discharge
187 m^3/s
2.3 m^3/s
Transported
sediments
silt, clay, cutbank
sand/silt/clay
In what ways is a meandering river different from a mountain stream?
From the visuals and the data, a meandering river is usually very flat (slope of 1.0m/km)
and a mountain stream has a slope of 22 m/km. The mountain streams have a faster
stream flow rate than the meandering river.
Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved
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