· A lesson that demonstrates the power of erosion through live-action modeling
Subject - Geography
Topic - Erosion
Grade Level - Third Grade
Duration – One 60-minute session
activity stimulates the imagination of children. Can they actually re-create a natural process in just fifteen minutes that
in nature takes hundreds of thousands of years?
Lesson Length - One and one quarter
of the perishable and imperishable aspects of life broadens the vision and makes a man see
beyond the ... limited sphere of daily life. " - Maharishi Mahesh Yogi in "Commentary on the Bhagavad Gita, Chapters
Discipline Wholeness of the Lesson:
and deltas around the world were created by the wearing-away effect of flowing water which is known of as "erosion"
"Science of Creative Intelligence" Wholeness Point:
" Every action has a reaction. "
The effect of water flowing by and "rubbing up against"
stone for thousands of years breaks away the stones surface, eventually causing riverbeds.
· What would the creation of a riverbed by erosion look like?
What determines the shape of a delta?
The world's surface is
undergoing a process of breaking down into smaller pieces by weathering and erosion.
smaller pieces are swept into rivers and carried to the edge of the sea where they are "deposited"
must protect their soil from being eroded away, through proper planting and tilling across
the face of hills.
Objectives of the Lesson:
· Children will understand by simulation one of the basic geographic formative processes of the world we inhabit -- erosion
· Children will be able to detect the dynamics of "silting" in the creation of their model river delta
· Children will gain a perspective on land-use
and protection of soil by this demonstration of the problem of erosion
of our natural soil resources
Group model-making and observation
by an experiment about erosion
Collabortive science experiment
Multiple intelligences and differences:
This activity uses minimal manipulative skills and therefore is accessible to physically handi-capped children. The excitement of "river" watching unites all children in the
suspense of the river channel formation process.
Special Application of Vedic Knowledge:
Protection from natural disasters of drought and soil depletion can be achieved by management of farming, and also by performances
of the music of nature - Ghandarva Ved Music - around the world.
been discussing the different kinds of land forms we may see in our world. Today, we will experiment with the process
of erosion that carves the face of the Earth into riverbeds, and even wears down
mountains over thousands of years."
"How would you like to make a mountain today in the
"We can all help by carrying sand for our mountain,
pouring rain on our mountain and watching our mountain-side turn into a riverbed. We can even name our mountain when we are done!"
· One blue tarp (approx 6 ft. x 8 ft.) and several five gallon pales
· Five bags of sand (50 lb. each), moisturized but not wet (as is standard with most play sand)
· Container of pea gravel to cover 3 ft. x 5 ft. area (1/2 inch deep)
· Small rocks – large gravel pieces, lava rocks, etc.
· Small evergreen bough ends, cut to 1 ½ to 3 inches
· One gallon plastic milk jugs (as many as there are students)
from a short section of the downward end of evergreen boughs, for later insertion into sand as “trees”
Cut a large
oval hole across top of milk jugs, leaving handle support in tact
Use a pointed
steak knife to poke/twist twenty-five 1/4 inch rough (not precise) holes in bottom of each jug
gallon pales with water (important - seperate from and cover containers away from small children.)
all building materials strategically around future construction area
open bags of sand; stow away ¼ bag separately as extra sand
up video camera, if desired
Student Procedures and Activities:
Children may briefly decorate their jugs with magic marker
drawings of rain and with cotton ball clouds. (These will wash off to some extent during the activity).
Note – All “mountain construction” is
done spontaneously, energetically, and without concern for small detail.
Lay blue plastic tarp down as base for mountain, and as
an “ocean” where the tarp protrudes from under the foot of the mountain. Spread a layer of pea gravel under the
entire projected area of the mountain base, up to and forming the projected beach outline at the oceans edge.
Have stronger children help to pour four bags of sand in
a rough mountain shape on top of the pea gravel (“earth crust”). Do not pack sand; its coarse scattered texture
is perfect as it is. Extend the future river side of the mountain (only) outward
in a long slope toward the edge of the sea. (Mountain base - approx 3ft. x 5 ft.)
Hollow out sand on entire top of mountain to create an
“underground lake” reservoir which, when covered with plastic, will collect water inside the mountain. Shape one
rim of the lake with a specific dip in it which will direct all the water to issue
from one location high up on the mountain side – the "source" of the river. See Figure One
Important: The bottom of the dip must be at least as low as the bottom
of the lake. Cover the lake bottom, rim and dip with a large cut-open tan-colored
plastic bag -- for example, a standard grocery bag. Cover all outward traces of the bag with sand and loose rock.
Pour the last bag of sand into a “mountain peak”,
directly on top of the bag and the lake bottom, filling the lake; cover this mountain peak completely with small rocks, to
later demonstrate the shifting of topography as land erodes and to slow down the
erosion of the peak during the experiment. Place similar “boulders” on the mountain sides (each child could place
one rock, “their” rock) and plant “evergreen trees” randomly, as well. Bury the outlet (dip) from
the underground lake using sand and small stones.
Children now begin the erosion experiment by filling their
“rain clouds” (jugs) with water from the five-gallon pails, by dunking them quickly in and out. Each child brings
one rain cloud swiftly to the top of the mountain, letting their rain pour onto the
rocks on top of the mountain. This has the effect of a "rainstorm" in the mountains. Children should follow immediately
after each other to create a continuous flow of water, representing “thousands of years” of precipitation.
Note: Children finished their rain-pouring should
gather at the foot of the mountain, watching from close to eye-level as the creation of the river proceeds. Expect joyful
The process: The water builds up in the underground lake
and spills out of the mountain side (via the dip), eroding away its sand covering. The water pours down the mountain, carrying
sand and rearranging the small rocks. The water creates a “riverbed” as the children watch on in excitement.
The teacher should supervise and verbalize energetically from behind the mountain while yet redirecting the
water if necessary. The process of erosion is natural and authentic in this experiment but may need quick assistance
occasionally to form one main channel of flowing water that will reach the sea. Smaller channels that do not use up too much
flow are also appealing and are a source of great enjoyment to the children as well.
Important: Do not stop the process of river creation once it has begun.
When all children have created their own rain storm, extra
five-gallon pales of water may then be carefully poured by the teacher or assistant on top of the mountain rocks to continue
the flow begun by the children.
Children should now take a step backward: the river will extend itself to
the very edge of the mountain and ocean shore. The water joins the sea and the sand will form faint delta-like patterns
as the water crosses the tarp.
A delta will form to the extent of the quantity of eroded sand in the water. Extra sand ("due to the weathering of rocks”)
may be fed into the rain channel at the top of the mountain by an assistant, to augment delta formation at the shoreline.
Cover any structural elements (such as the edge of the underground lake) with loose sand when the project is done, in order to
improve the naturalness of the scene.
Events may be video-taped in close-up detail with many
eye-level and/or slow motion shots, etc. for later classroom study of the process and power of erosion.
Fulfilment and Closure:
Today we have discovered two things about the surface of our earth -
power of erosion of the Earth's land and soil carved
all of her riverbeds.
action of silting creates fertile deltas on major river systems, such as the Mississippi River Delta in
Associated Activities for Extended Assessment:
· In the classroom before the experiment children may find on a world
map or globe seven rivers of the world, large or small / and three river deltas.
· As the students venture
out to the playground to create their very own mountain and river, discuss the sense of kinship that Native Americans
have for the mountains, lakes and prairies that they share with nature
· Afterward, children may
name the mountain and river which they have created and discuss what life would be like living by
or in a river delta
could show the video of “The Power of Erosion” to other classes, with a guided tour of their “mountain in
a playground” to follow.
“Pet rocks” may be created by the children. These are created from pieces of rigid pink foam insulation
board and the use of tongue depressors that are glued to sandpaper (halfway in length) and then trimmed, creating an easy
tool for small hands to work with to mimic the steady force of wind-borne sand and of water in eroding rock surfaces.