Soil Texture and Stream Flow

1
Soil Texture and Stream Flow
Teacher Guide
This activity introduces students to the
structural differences in soils and the forces of
moving water. Students use field techniques to
test soil samples and key out soil texture
class and subclass using a soil texture flow
chart (containing the soil texture triangle). The
water flow section of the lesson is completed
using a stream table.
Overview
Science Process Standard 1-1 Content Standards
5-1, 5-2)
Oklahoma PASS Objectives
National Science Education Standards
Physical Science Standards (motions and forces)
Science in Personal and Social Perspectives
(natural hazards) Scientific Inquiry Standards
(ability to do scientific inquiry) Unifying
Concepts and Processes Standards (models and
explanation).
Middle School. Stream flow can be completed in
elementary grades. Can be modified with
additional questions for higher levels.
Grade Level
Other Skills
Students should have a basic understanding of
variations in soil particle size. Students
should have an introduction to stream flow and
how it can alter stream channels. An alternative
is to not provide students with previous
knowledge of channel morphology before conducting
the activity. Students will experience stream
flow when engaged in the activity.
Should be completed in one 50-minute class.
Time
Note to Teacher
You can obtain a USDA Soil Texturing Field Flow
Chart from Forestry Suppliers (forestry-suppliers.
com). This will allow you to conduct tests for
texture class and texture subclass. A stream
table may be purchased or you can build your own.
It should be at least 3.5 feet long by 2 feet
wide and watertight. Instructions may be found at
this website (http//www.pbs.org/americanfieldgu
ide/teachers/floods/stream_table.pdf)
Teacher Guide p. 1
Soil Texture and Stream Flow
2
Prairie Dog Town Relocation
Teacher Guide
Materials
- USDA Soil Texturing Field Flow Charts - 3 soil
samples - 3 spray bottles (capable of mist) - 3
tubs - 3 wash bottles - stream table appropriate
soil for stream channel analysis (fine- particle,
clean sand works well) - 2-3 short 1x4 boards
used to increase the slope (gradient) - plastic
houses such as those found in the Monopoly board
game.
Lesson Preparation
Place the three soil samples at different
stations around the room. At each soil station,
there should be a soil texture flow chart, tub,
spray bottle, and wash bottle. Students will need
the student activity sheets found in this lesson.
The stream table should be arranged so that you
have complete access to all sides. You have to be
able to input water at the top of the stream
table as well as drain water at the bottom.
Create a channel for the water to flow. The
channel should have at least one strong curve in
it. This will allow the channel to meander as
the water flows through it. Students will place
their houses along the bank of the stream before
the water begins to flow.
Assembled by Brad W. Watkins brad.watkins_at_okstate.
edu Adapted from Micozzi, Mark, et al.. Physical
Geography Laboratory Exercises Viewing the Earth
as a System
Teacher Guide p. 2
Soil Texture and Stream Flow
3
Soil Texture and Stream Flow
Name __________________________ Hour _____
Soil texture refers to the size and arrangement
of soil particles. Soil textures are examined
using a soil texture flow chart. All soils are
composed of some combination of sand, silt, or
clay along with air, water, and organic matter.
The amount of sand, silt, or clay, will determine
how well the soil support vegetative cover. The
most type of soil most productive for plants is
known as loam, and is found at the center of the
triangle.
Particle Diameter Sand 2 mm 0.05 mm Silt 0.05
mm 0.002 mm Clay lt 0.002 mm
Using the soil texture triangle on the handout,
determine the texture classes of the examples
below 70 clay, 20 sand, 10 silt
_________________________________ 60 silt, 10
sand, 30 clay _________________________________
60 sand, 10 clay, 30 silt ___________________
______________ 20 clay, 40 silt, 40 sand
_________________________________ 70 silt, 10
clay, 20 sand _________________________________
Use the flow chart provided to determine the
texture sub-class at each station. Station 1
_____________________________ Station 2
_____________________________ Station 3
_____________________________
Soil Texture and Stream Flow
p. 1
4
Soil Texture and Stream Flow
Name __________________________ Hour _____
Learn about soil stability at the stream table
station.
Stream tables are simple models of the streams
you would find outside. The word stream also
refers to creeks and rivers. Streams are very
interesting to study because they are always
changing. As water flows through the channel of
the stream, the force of the water as it goes
around a bend in the stream channel speeds up.
This fast water can cut into the side of the
stream bank and cause the channel to shift over
time (see example below).
fast flow
slow flow
direction of flow
Now you know how water in a stream can move at
different speeds depending on its location in the
channel. You know that the channel can move,
called meandering. Now think about how this might
affect the surrounding area over time. Real
World Pretend you are building a home and you
want it to have a view of the river. You can
choose anywhere to build your home on either side
of the stream. 1. Place your Monopoly house at
some point along the stream. (Do not push the
house into the sand.) 2. Wait for your teacher to
start the stream flow. Notice what happens to the
stream channel, your house, and the houses of
others.
Answer the questions on the next page.
Soil Texture and Stream Flow
p. 2
5
Soil Texture and Stream Flow
Name __________________________ Hour _____
Answer the following questions about the stream
flow station.
1. How would this lesson affect your decision to
build a home near a river?
2. Using what you learned about the different
types of soil textures, soil structure, and
stream flow, why do stream channels move so
easily (think about the type of soil you would
find in and along streams)?
Soil Texture and Stream Flow
p. 3
6
Soil Texture and Stream Flow
Name KEY Hour
_____
Soil texture refers to the size and arrangement
of soil particles. Soil textures are examined
using a soil texture flow chart. All soils are
composed of some combination of sand, silt, or
clay along with air, water, and organic matter.
The amount of sand, silt, or clay, will determine
how well the soil support vegetative cover. The
most type of soil most productive for plants is
known as loam, and is found at the center of the
triangle.
Particle Diameter Sand 2 mm 0.05 mm Silt 0.05
mm 0.002 mm Clay lt 0.002 mm
Using the soil texture triangle on the handout,
determine the texture classes of the examples
below 70 clay, 20 sand, 10 silt clay 60
silt, 10 sand, 30 clay silty clay loam 60
sand, 10 clay, 30 silt sandy loam 20 clay,
40 silt, 40 sand loam 70 silt, 10 clay, 20
sand silt loam
Use the flow chart provided to determine the
texture sub-class at each station. Station 1
_____________________________ Station 2
_____________________________ Station 3
_____________________________
Learn about soil stability at the stream table.