Artistic Expression Lesson Plan
Submitted by: Angela Teubert
Subject and Grade Level: 7th-8th
Title: W3 ;Wind Water Waves
Purpose:
I am teaching this particular unit to help kids better visualize and understand how different types of erosion affect the landscape.
Overview of content:
Erosion is the natural process by which soil and rocks are moved by wind or water along the earth's surface.
River Erosion
Mature rivers flow across wide river valleys and meander or snake across the flat plains. These meandering streams create large loop meanders that develop into oxbow lakes adjacent to the stream.
As a mature river begins to curve, it cuts and erodes into the outside of the curve and deposits sediment on the inside of the cure. This is due to the fact that the stream moves more rapidly on the outside of the curve and more slowly on the inside of the curve. Thus, as the erosion and deposition continues, the curve becomes larger and more circular.
Eventually, the loop of the curve reaches a diameter of approximately five times the width of the stream and the river begins to cut the loop off by eroding the neck of the loop. Eventually, the river breaks through at a cutoff and forms a new streambed.
Sediment is then deposited on the loop side of the stream, cutting off the loop from the stream entirely. This results in a crescent-shaped lake that looks exactly like an abandoned river meander. Such lakes are called oxbow lakes because they look like the bow part of the yoke used with teams of oxen.
Beach Erosion
Fact: Beaches erode. This has been a problem in many coastal communities. However, erosion is the thing that initially created the beaches. When oceans first covered the surface of the earth millions of years ago, there were no beaches. There were only rocky shores. Over the course of millions of years, these solid stones were broken down into rocks by erosion, which in turn were broken down into pebbles, and then into gravel, and then into sand. Rivers also carried down silt and sand from the mountains and deposited it into the oceans and seas of the world.
There are many causes of beach erosion. Most of them are natural. These are currents, storms, earthquakes, winds, waves, tides, and also the gradual movement of tectonic plates. Some beaches are also destroyed by men when harbors are built, or any other structures that disrupt the fragile balance of nature.
Waves are probably the most important components of beaches. Everyone likes waves. Waves form as the result from deep ocean currents, winds and the rotation of the earth. Although waves look like large volumes of water moving in and out of the shore, they really aren't. Water moves very little in waves, in circular paths perpendicular to the ground. Waves take sand from the depths of the ocean and deposit it on our beaches. Waves also carry little stones and pebbles, and smash them into each other producing sand in the first place. Waves can also be harmful though. When waves get large and are powered by storms, they break much higher on the beach and when they wash back down to the ocean, they take sand with them.
Wind erosion
Wind erosion, unlike water, cannot be divided into such distinct types. Occurring mostly in flat, dry areas and moist sandy soils along bodies of water (sand dunes), wind erosion removes soil and natural vegetation, and causes dryness and deterioration of soil structure. Surface texture is the best key to wind erosion hazard potential. All mucks, sands, and loamy sands can easily be detached and blown away by the wind, and thus are rated a severe hazard.
Estimated Time Commitment:
1 week for this activity if you choose to expand on this idea it will take longer.
Learner Expectations:
Student will be able to…
*Identify why water, wind, and wave erosion happens.
*Draw where major portions of erosion happen.
*List the different causes of erosion
*List ways to prevent erosion.
Activities and procedures:
Materials:
Water table
Sand
Water
Plain paper for students
Lego's or toys of houses, trees, and people
River Erosion
Using a water table set up what a meandering stream looks like with houses, trees, and other items you might find around a stream.
With no knowledge about stream erosion students will have observe the water table, pointing out certain items such as where the water source is located, where the water ends up and any other toy/learning item on the water table.
Once they have observed the water table with only the prior knowledge they have they will return to their desk and make two drawings, one of what the stream looked like and one that predicts what the stream will look like when water is flowing through the stream.
When finished with drawings have a discussion on why they have made the drawing they did. Mention different terms they will need to know.
Then return to the water table and turn the water on. The student will observe what happens, where the major erosion happens, where the sediment is deposited. After the water has been running for a while some of the meanders will begin to change form and an oxbow lake will begin to form.
When finished observing the student will return to do a third drawing. In this drawing have students place labels and definitions on their drawings where appropriate.
Second Erosion Activity: Beach
Using the sand table again make a beach shoreline. The sand back should be about 2-3 inches deep and should gradually slope toward the center of the water table (I usually place some books at the top of the table so the table also has a slope to it.) Be creative with the shoreline design, shorelines are rarely straight across. Add realism to your design by placing a few rocks and stones in your sandbank.
Sprinkle a thin layer of colored sand over the sandbank. Fill the water table at the bottom with about 1 to 2 inches deep of water.
Have students sketch what the shoreline looks like currently so that they will be able to recall its initial appearance later.
Place a 4x2 piece of wood at the end of the table so you can create waves. Move it back and forth to create a series of gentle waves. Uniform, controlled waves will have the best results. Observe the shoreline as you continue to make waves for a full minute. What happens to the colored sand as the waves hit the shoreline? (Have students answer the questions on sheets of paper as they are observing the lab)
Make another quick sketch of the shoreline now.
Have students now predict what will happen to the shoreline if you create waves with gradually more force.
Now experiment with waves of increasing force. You might try making waves that hit the shoreline at different angels. Observe the sand back as you continue to make waves for a full minute.
Have students now write if their prediction was correct. What happened to the sandbank as the waves became more forceful? Make a final Sketch.
You can take this further by having students conduct experiments on how you could control erosion. Or you can just have a class discussion.
Wind Erosion
Using the water, remove all of the water and let the table sit over night.
Make 2 different colors of sand (blue and red) and let sit over night to dry.
Create a "dune" by pouring the red sand in a straight line on one side of the sandbox. The dune should be about 8 inches wide and 2 inches deep.
Using the blue sand, create another dune of the same size behind and adjacent to the red one.
Using the uncolored sand, create 2 more dunes, each the same size as the previous ones, behind and adjacent to the blue one.
Predict how the sand will be affected by a horizontal wind blowing directly into the dunes.
Use the wind source (blow dryer) to create a horizontal wind blowing directly into the dunes. Start with a fairly low wind speed and then increase it. Continue until about half the red sand has been eroded. Note any changes in the behavior of the dunes and the particles of sand at different wind speeds.
Observe the distribution of the colored sand particles. Are there any differences in the distributions of the red and blue particles? Are there any differences in the distributions of particles of different sizes?
How does changing wind directions affect dune erosion? Find out by blowing wind across the dunes from different directions.
How does water influence wind erosion of the dunes? Spray the dunes with varying amounts of water before applying wind to them. Note: The food dyes are water-soluble and may separate from the colored sands. Take precautions to avoid stains.
How do plants influence dune erosion? Use dried lichens to model shrubs on your dunes. Apply wind to the dunes and see what effect the shrubs have on erosion.
Do plants act only as barriers at the surface, or do their roots also affect dune erosion? Look into this question by partially burying a shrub in a dune and setting another shrub on the surface. Apply wind to the dune and then compare the erosion around the 2 shrubs to see if there is a difference.
Resources/ materials:
2002 Carolina Biological Supply Company, 7/02/02.
Krys Cybulski, 7/02/02.
Holt Science and Technology Lab, lab, and more labs, 2001.
Closure:
After the lesson is done we will take a field trip to local areas where erosion is currently happening.
Performance Assessment:
Students are to write a lab report for the experiments we preformed in class. These consist of drawings, answers to questions and any other notes we have taken during this unit. The lab report is graded on how through it is done and if all items are included.
Standard Benchmark:
Geosphere (EG) #3
Explain how rocks are broken down, how soil is formed and how surface features change.
Key concepts: Chemical and mechanical weathering: erosion by water, wind and downslope movement; decomposition.
Regions in Michigan where erosion by wind, water or glaciers many have occurred, such as river valleys, gullies, shoreline of Great Lakes; chemical weathering form acid rain, formation of caves, caverns and sink holes; physical weathering, frost action such as potholes and cracks in sidewalks; plant roots by bacteria, fungi, worms, rodents, other animals.
