why should i care about soil erosion? -...

AKSCI ©2011 Alaska Department of Education and Early Development Why Should I Care About Soil Erosion?

WHY SHOULD I CARE ABOUT SOIL EROSION?

Overview:In this lesson, students explore soil erosion both inside and outside of their classroom and will explore, suggest, and hypothesize ways they can minimize erosion in their community.

Objectives:The student will:• identify different types of soil erosion;• explain at least one reason why they should care about soil erosion;• analyze strategies for soil conservation; and • evaluate best practices for soil conservation.

Targeted Alaska Grade Level Expectations: Science[7] SD2.1 The student demonstrates an understanding of the forces that shape Earth by identifying strategies

(e.g., reforestation, dikes, wind breaks, off road activity guidelines) for minimizing erosion

Vocabulary:erosion - the incorporation and transportation of material by a mobile agent, such as water, wind or icesoil - a combination of mineral and organic matter, water and air

Materials:• Soil erosion data (one per student or group)• Potted plants (preferably one that is root-bound and one that has not out-grown its pot)• Watering cans with sprinkle-type heads or large paper cups with holes poked into the bottom• Pint-size containers (vessel for water)• Samples of dirt, sand, potting soil and gravel (approximately 4 quarts each)• Containers to hold extra samples of dirt, sand, potting soil and gravel • Small stones and large pebbles• Plastic bins or aluminum baking trays—with several holes poked at one end to form a “drain”• Tissues• Bottle caps• Fans (if fans are unavailable, students can blow through drinking straws to create “wind”)• Drinking straws (optional)• STUDENT WORKSHEET: “KWL Chart”• POWERPOINT: “Erosion”

Activity Preparation:1. Prepare activity stations. Each station should have:

• Earth medium (sand, gravel, soil, dirt): one station should have a mixture medium of sand, gravel, dirt and potting soil.

• Plastic bin with holes poked at one end to form a “drain”• Watering can• Pint-vessel• Fan• Variety of bottle caps, stones and pebbles• Water• Tissues



2. As students enter the room, project the POWERPOINT: “Erosion” with rotating images of soil erosion.

Teacher’s Note: Depending on the size of the class, students can be responsible for one earth medium (and report findings to the other students), or students can rotate stations. If each student participates in each station, more time should be allotted for the activity. Additionally, students will need extra data sheets. This activity could be conducted outside to minimize cleanup time.

3. Pass out the STUDENT WORKSHEET: “KWL Chart” and have students fill in the “K” and “W” for the three questions: • What is soil erosion?• Why should I care about soil erosion?• What can I do to prevent soil erosion?

4. After students have had time to write down their ideas, have them share their thoughts. Direct the conversation into the first activity (see below).

Teacher’s Note: Explain to students that it is ok if they only have guesses for the “know” column. If they don’t feel like they know anything, they should write their hypotheses. Students should know that they will not be graded on the correctness of their ideas.

Activity Procedure:1. From the KWL discussion, begin to discuss how plants help to hold earth together and why erosion can be

problematic.

2. To illustrate this idea, take the potted plant out of its pot, with the soil intact. Discuss how the roots help to keep the soil together. Ask what would happen if the plant was not in a pot, but in the ground and water was running over it.

Teacher’s Note: A root-bound plant works well for this demonstration. Students can touch the dirt and see how difficult it is to break apart. You can compare and contrast it with a plant that is not root bound to illustrate how more roots in the system give it more stability.

3. Introduce the terms soil and erosion; discuss how wind, water and ice can cause erosion. Ask students if and where they have seen the effects of erosion. Elicit from students some problems that erosion can have for the local community (ideas might include: damage to fish spawning areas, reduced visibility for aquatic organisms, reduced light infiltration for photosynthetic plants and algae, damage to roads [and other infrastructure], changes in migration patterns for animals, economic impacts). Write student ideas on the board and leave them up while students move through the lab activities below.

4. Discuss that erosion is not always problematic. It is a necessary process of nature and may be essential to some ecosystems. Along with sediments, often come nutrients that many plants/animals would not get otherwise. Note: human-caused erosion is what alters ecosystems, not natural erosion.

5. Plaina. With students at their stations, instruct them to fill their tray with earth medium, patting it down and

smoothing it so that it fills the whole bin to create a “plain.” b. Instruct students to press small stones, gravel, and / or bottle caps at various places into the earth. c. In groups or individually, students create a hypothesis about how the earth will be affected when it is

“windy” and when it “rains.”d. To simulate wind, have students hold a fan over the earth basin. Students should test different wind

speeds use and move the fan around the top and sides of the basin. e. In pairs, groups, or individually, students record movement and changes, noting differences when the

wind is in different locations/speeds.



Teacher’s Note: If fans are not available, use drinking straws of various sizes and have students blow through them to create the “wind.”

f. Next, students will create “rain” on their earth. One student holds the watering can 12 inches above the “plain” and waters evenly across the bin.

g. Have students experiment with the “force” of the rain by moving it farther and closer to the earth, experimenting with the amount of volume, etc.

h. Students record any changes or movements they see in the earth or the stones/bottle caps.i. Students write a conclusion about their observations: How does the size of the particles affect the rate

of erosion? Would the volume of water or the hardness of the rain, affect the rate of erosion?

6. Mountain Without Grassa. Instruct students to shape the earth medium into a pile to form a “mountain.”b. Ask students to follow the same steps as above, and record their observations. Be sure that students

note any differences between the earth as a “plain” and the earth as a “mountain.”c. Conclusion: If you wanted to control erosion on a hill, what type of material would you use to do this?

Do the bottle caps affect the rate of erosion? How can you apply this lesson to a hill in your area? (How would you help prevent erosion on a hill?)

7. Mountain with Grassa. Direct students to shape the earth into a “mountain.”b. Next, have students cover the mountain with a tissue. This represents grass or other vegetation growing

on the hill. Guide students to pat the tissue down lightly so that it is touching the earth everywhere. c. Tell students to follow the steps above and note their observations, being certain to note differences

from the “plain,” “mountain,” and “mountain with grass” stages.d. Conclusion: Would planting vegetation on all hills change the rate of erosion?

8. River without Vegetationa. Direct students to spread the earth out flat in the bin and pack it down. Then, create a two-three

inch wide “river” by forming a cut through the earth from one end of the bin to the other. Encourage students to create their “river bed” with curves like a natural river.

b. Ask students to place some gravel in the bottom of their riverbed.c. Holding the bin at a slight angle (with the drain end lowest), instruct students to slowly pour a pint of

water down their “river bed.”d. Instruct students to make “rain” at the headwaters using the watering cans.e. Students should note their observations (including erosion along banks, how gravel moves in the bed,

what difference the amount of water makes, etc.).f. Conclusion: How does erosion affect river bends?

9. River with Vegetationa. Have students set up a second “river.”b. Students should line the “banks” of their rivers with small stones and tissue-grass.c. Repeat steps of the “River without Vegetation” process and have students record their observations.d. Conclusion: How does vegetation change the erosion in the river? How could this be applied to rivers

in your area? What might be some difficulties of this method? (Some riparian zones do not support vegetation.)



Assessment:1. Have students present their observations and conclusions from their station to the rest of the class. As

students present their findings, help them articulate what they have learned about erosion, what things affect the rate of erosion, and finally what things can be done to help slow erosion.

2. Revisit the problems that students talked about at the beginning of class. Have them suggest ways to mitigate those problems. Use the notes on the board to create a mind-map of solutions (tying each problem or set of problems to a set of solutions).

3. Have students return to the STUDENT WORKSHEET: “KWL Chart” presented at the beginning of class. For each question, students must identify and explain at least one answer. In addition, from a list of possible conservation strategies (developed during the course of the lesson), ask students to evaluate which would be most successful. Use the KWL chart as an “exit card.”

Teacher’s Note: As an exit card, all students are required to turn this in before they are allowed to leave the class. Take a quick scan of the “L” column to ensure that there isn’t any confusion / misunderstandings. If there are misunderstandings, plan to start the next lesson clarifying those.

Community Action / Involvement:

Teacher’s Note: The following activities are optional. Depending on time, the following activities can help students further internalize the issues and make them more relevant by applying them to their own lives.

1. Take a walk around campus, in town, or through the village. Have students note areas where they see erosion happening.

2. Students research the problems that erosion is causing for the community.

3. Students work in teams to develop a plan to mitigate the erosion problem.

4. Students present their action plan to the village council.

Resources:1. Eco-Connections: Walker-County Russian Innovative Project http://www.walkerschools.org/eco/soil3.html

2. Water and Soil Erosion http://www.eduref.org/Virtual/Lessons/Interdisciplinary/INT0133.html

3. A to Z Teacher Stuff http://www.atozteacherstuff.com/pages/298.shtml

4. Science Net Links http://www.sciencenetlinks.com/lessons.php?DocID=454


NAME: __________________________ KWL CHART

Know

Wan

t to

know

Lear

ned

Wha

t is

soil

eros

ion?

Why

sho

uld

I car

e ab

out s

oil e

rosi

on?

Wha

t can

I do

to

prev

ent s

oil e

rosi

on?


NAME: __________________________

Activity Purpose:

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

Hypothesis:

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

Procedure:

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

Data (what happened):

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

Conclusion:

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

Erosion

1. “Ba

nk Erosion

.” Pho

to by Amy Clapp (TRE

C 2005), Co

urtesy of A

RCUS.

hFp://med

ia.arcus.org/displayim

age.ph

p?po

s=-‐13255

2. “Erod

ed Scarp.” Pho

to by Misty Nikula (PolarTR

EC 2007), Cou

rtesy of ARC

US.

hFp://med


age.ph

p?po

s=-‐26417

3. “Stud

ying Coastline Erosion 2.” Ph

oto by Frank Kelley (PolarTR

EC 2008), Cou

rtesy of

A

RCUS. hFp://med


age.ph

p?po

s=-‐30692

4. “Selawik Slump.” Ph

oto by Ben

Crosby. Cou

rtesy of Alaska Science Forum

hFp://www2.gi.alaska.ed

u/ScienceForum

/ASF19/1974.html

5. “Creek Erosion.” Ph

oto by SoilScien

ce.info. Cou

rtesy of Flickr CreaZ

ve Com

mon

s.

hFp://www.flickr.com

/pho

tos/soilscien

ce/5084844060/sizes/o/in/pho

tostream

/ 6. “Trail Erosion

.” Pho

to by And

y Arthu

r. Co

urtesy of Flickr CreaZ

ve Com

mon

s.

hFp://www.flickr.com

/pho

tos/andyarthur/5670648941/sizes/l/in/pho

tostream

/

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