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Erosion.

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Rocks change, Rocks break apart. Rocks move. Rocks erode (e-rode). Water and ice erode rock. Wind erodes rock. Can you see the changes?

New Words:

change

break

erode

ice

Wind

NOTE TO TEACHERS and PARENTS

(See directions in Teaching Notes for all activities.)

Vocabulary

Move the word! Copy the letters.

erode

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Adult Supervision Required

Weekly Lab

Make it rain. What will happen to the soil?

You need: two foil trays, pointy scissors and an adult to help, soil, books, water, and a watering can,

Step 1: An adult should poke 6 small holes in one end of one tray with the pointy scissors.

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Step 2: Pour dirt into this pan to make a layer 5-7 cm thick. Smooth the soil flat.

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Step 3: Put the end with holes in the other tray. Rest the other end on a stack of books.

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Step 4: Pour rain with the watering can onto the soil on the raised end. What do you think will happen? Pour the water slowly. Pour it fast. What happens?

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Math

What happened? How many rocks are there now?

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How many rocks at the bottom of the hill?

-

How many rocks at the top of the hill?

=

How many more rocks are at the bottom of the hill?

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Writing in Science

What happened when you made it rain? Write 1 to 2 sentences about what you saw.

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Adult Supervision Recommended

Challenge

Erosion in action!

Will the paint wash away?

1. Put a coffee filter in a funnel over a jar.

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2. Mix some powdered tempera paint with some dirt,

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3. Put this in the funnel.

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4. Pour water over the dirt.

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Talk about what happened.

Adult Supervision Recommended

Bringing it Home

Ice can break rock, Do you know how?

1. Fill a small plastic container with water, Fill it to the top.

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2. Put the lid on, Make it tight, Be careful not to spill any.

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3. Put it in the freezer overnight.

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What do you think will happen? Talk about what happened.

"Some fish use electricity to find food."

"Some fish use electricity to move safely through dark water."

"You'll learn all about electric animals in our next issue."

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Materials Needed for this Issue

Level Pre-A: two aluminum foil lasagna-type trays, dirt (not potting soil), water, watering can, pointed scissors or something sharp to poke holes, pencils with erasers, bars of soap, sponges, dripping water faucet, pencils

Levels A and B: two aluminum foil lasagna-type trays, dirt (not potting soil), water, watering can, pointed scissors or something sharp to poke holes, measuring cups and spoons (that show milliliters) or a graduated cylinder, powdered red tempera paint, coffee filters, funnels, big jars, small plastic containers with lids (food or yogurt containers work well), freezer, notebooks and pencils

Level C: two aluminum foil lasagna-type trays, dirt (not potting soil), water, watering can, pointed scissors or something sharp to poke holes, small to medium rocks, measuring cups and spoons, powdered red tempera paint, coffee filters, funnels, big jars, notebooks and pencils

Levels D and E: two aluminum foil lasagna-type trays, dirt (not potting soil), water, watering can, pointed scissors or something sharp to poke holes, small to medium rocks, rectangles of cloth large enough to cover the trays, steel wool (without soap, which can be purchased in a hardware store), salt, hard candy (like Jolly Ranchers[R] or Starlight Mints[R]), stopwatch or clock with second hand

DID YOU KNOW??

Erosion removes topsoil first. Once the topsoil is gone, few plants can grow again. Without soil and plants, the land becomes a desert and unable to support life. This is called "desertification" (de-ser-ti-fi-ca-tion).

Background

Weathering

Our natural landscapes change constantly, in large part because of weathering and erosion. Weathering is the natural breakdown of rocks into smaller particles. Chemical weathering occurs when the chemical nature of the minerals in rocks changes. For example, rainwater is naturally acidic and this mild acid can dissolve, or eat away at rock. This is why rock sculptures become smoother over time. Many rocks have iron in them and thus rust. Lichens are plants that can cover rocks and break them down.

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TEACHING NOTES (TN)

Supplement to Science Weekly Publication Pre-A through E

Mechanical weathering occurs when rocks break apart but their chemical composition does not change. Rocks break apart when they fall down a hillside or when bounced around in a fast moving river. Glaciers carry rocks and sometimes scrape them against the bottom and wear them down. Water seeps into cracks, and if it freezes, the ice can break a rock apart. Wind can drive sand against rocks and wear them away.

Erosion

Any time a rock is broken down, it is called weathering. When rocks actually move from place to place, this is called erosion. Rocks and mud sliding down a hillside, boulders moving downstream, and grit being carried by a glacier are all examples of erosion. The difference between weathering and erosion is sometimes a subtle one, and it is not important for children in the younger grades to make the distinction.

Erosion and People

Sometimes erosion has disastrous effects on people. Wind can blow valuable topsoil away. The most famous example is the great Dust Bowl of the 30s, but it is happening all the time. Mud slides can bury homes. Beach erosion can cause homes to collapse. Sinkholes can suddenly open up and swallow buildings. And, of course, road potholes challenge all drivers. People are learning their lessons from nature and learning to build in different areas. Farmers are learning to keep their soil covered with plant material year-round. Weathering and erosion are natural processes that are both fascinating and relevant to our children's lives.

Initiating Questions Levels Pre-A--B

1. Does the land around us ever change?

2. Have you ever seen moving rocks?

3. What happens when it rains too much?

Follow-up Activities Levels Pre-A--B

1. Build a mountain of dirt outside. Observe it over several months to see what happens.

2. Take a walk outside and look for examples of erosion.

SAFETY STICKY NOTE

The teacher or other adult should use the pointed scissors to poke holes in the trays ahead of time, or be available to closely supervise the older students.

Follow school guidelines regarding food safety, and make sure students are allowed to eat sugar and food coloring or additives in the candy beforehand.

Level Pre-A

Main Concepts: Rocks break apart and often move.

DID YOU KNOW??

Sediment from erosion, blowing around in the air, is one of the greatest pollutants in the world.

Picture Activity

Ask your students to describe the picture. Make sure they notice the boulders. Ask them if they see any rocks moving. Ask if they know what happens to rocks when they move.

Vocabulary

Read the sentences out loud to the class to reinforce the new words learned on page 1. Explain again that when rocks break, they erode. It is called erosion. Students will circle the broken rock--the rock that has eroded. Finally, students trace the word erode.

Weekly Lab

(See MATERIALS NEEDED on page 1.) Use two foil trays for each group of children. Poke holes into one end of half the trays ahead of time. Tell your students to put dirt in the tray with holes in it, a couple of inches deep, and then smooth it out. Set the end with holes on the other tray. Rest the opposite end on a stack of books. Ask the children to predict what will happen when they make it "rain" onto the dirt. Tell them that soil is another word for dirt. Plants need good soil to grow. Ask the children to pretend it is raining. Have them slowly pour water at the top of the "hill" and watch closely to see what happens. Make sure they observe all areas of the tray with soil, as well as in the receiving tray. Regular dirt works better than "potting soil." Ask students, "What is happening?" Ask, "Where does the soil go?" Explain that the same thing happens when it rains outside. Ask what they think would happen to the soil if a hurricane came, or a tornado. Water erodes soil and washes it away. Wind erodes soil, too, and blows it away.

Math

Ask your students to predict what will happen to the rocks when they hit the boulders and the water. (They will break, fall apart, wear down, erode, get smaller and smaller and be carried away by the water.)

Answer: 3 + 5 = 8

Storytelling

Have your students tell each other what they saw happen during the WEEKLY LAB activity. Ask them if they have ever seen this happen outside.

Challenge

Provide students with paper and pencils with good erasers. When the student erases his name, point out that this is like one rock rubbing against another and breaking it up. When he blows on the dust, this is like a strong wind picking up sand and soil and moving it away. Remind students what happened when they made it rain on the soil. Just as water can "erode" rock, so can wind.

Bringing It Home

You can either ask the students to let the water drip overnight and look to see what happened in the morning, or tell them to leave the water running with a stronger stream and see the results in about an hour. In either case, tell them to make sure that the drain is still open to prevent the sink from filling.

If the bar of soap does not easily stay in place, it could be placed on a sponge. Tell students it would be a good idea to have some adult supervision for this activity.

Level A

Main Concepts: Rocks can change. Rocks move and break apart. Water, ice, and wind erode rocks.

Picture Activity

(See Level Pre-A.) Ask students if they know what glaciers are. Tell them that in addition to wind and water, ice can cause erosion, too. Water can get into the cracks of small rocks and freeze. That will crack the rocks and break them. But, glaciers carry very big rocks along with them for great distances, and wear them away.

Vocabulary

Students will copy (move) the letters of the word erode to the blank lines. Explain that when rocks move that is called erosion.

Weekly Lab

(See Level Pre-A and the SAFETY STICKY NOTE.) Direct the students to pour the water slowly at first, and then faster. Ask them if they notice any differences. Explain that this is what happens to the soil outside when it

rains. Tell them that farmers need to find ways to keep their good soil from washing away.

Math

Remind your students that when rocks fall down a hill, they sometimes break up into smaller pieces. This is erosion.

Answer: 8 - 2 = 6

Writing in Science

(See Level Pre-A--STORYTELLING.)

Additionally, students will write 1-2 sentences about what they saw happen.

SAFETY STICKY NOTE

The teacher or other adult should use the pointed scissors to poke 6 holes in half of the trays before beginning the WEEKLY LAB.

DID YOU KNOW??

Scientists have determined the best ways to prevent or repair erosion damage are by: maintaining a constant ground cover of plants, reforestation, terracing, drainage ditching, deeper plowing, and plowing across slopes rather than up and down.

Challenge

Have your students thoroughly mix a small spoonful of red powdered tempera paint with about a half cup of dirt. Students should pour the water slowly, making sure that it does not overflow the funnel. Regular soil works better than potting soil. Make sure your students carefully observe what happens in the jar below. Point out that the important nutrients in soil that plants need to grow can sometimes be carried away, just like the red paint, when it rains too hard.

Bringing It Home

Small, plastic food or yogurt containers with lids work well. Make sure students add the water slowly so that it bulges up before carefully sealing the lid on it. After the water freezes and students can see what happens, ask them to think about what this might do to rocks when water freezes in the cracks. If the lid stays on tightly, the container will bulge out and may even crack. If the lid pops off, you can ask your students why they think that happened, and what this could do to rocks.

Level B

Main Concepts: Wind, water, and ice can change rocks. This is called erosion. Erosion can break down rocks, move them, and wear them away. Rocks get smaller and smaller.

Vocabulary

Tell your students that when rocks break down it is called erosion. Explain that words can be broken down just like rocks. The letters, or smaller pieces of rock, can then move and be rearranged. Students will rearrange the letters to make a new word.

Answer: erosion

Weekly Lab

(See MATERIALS NEEDED on page 1 and Level A--CHALLENGE.) You will need a measuring cup and spoons that show milliliters (or use a graduated cylinder). You will need it for the following MATH activity. Make sure your students carefully observe what happens in the jar below. When the water has finished dripping, have them measure how much water is in the jar.

Math

Use the measurements (in milliliters) from the WEEKLY LAB activity. Answers may vary.

DID YOU KNOW??

Landmasses today are eroding at a rate of 2-3 cm (1 in)

Writing in Science

Point out to students that the important nutrients in soil that plants need to grow can sometimes be carried away when it rains too hard, just like the red paint in the WEEKLY LAB activity. Ask your students to think about what this means for farmers and then ask them to write a few sentences.

DID YOU KNOW??

In the U.S., 30% of erosion is caused by natural forces, while 70% is caused by human activity.

Challenge

(See Level Pre-A--WEEKLY LAB and THE SAFETY STICKY NOTE). After your students have had a chance to try this at least once, challenge them to predict where the water will go and see if they can make the water go where they want it to go. Explain that farmers need to be able to control soil erosion.

Bringing It Home

(See Level A.) For a control, ask your students to set up two containers, one to put in the freezer and one to leave out.

Initiating Questions Levels C--E

1. What happens to the land when it rains too hard?

2. Can big rocks ever move? How?

3. How do canyons form?

Follow-up Activity

1. Build a mountain of dirt outside. Observe it over several months to see what happens.

2. Take a walk outside and look for examples of erosion.

Level C

Main Concepts: Rocks weather when they break down. Wind, water, and ice can weather rocks. Erosion occurs when wind, water, and glaciers move the rocks from one place to another.

Vocabulary

When providing examples, make sure your students use as many of the bolded words on page 1 as possible.

Answer: Weather can be a noun referring to conditions of the atmosphere such as temperature, moisture, and wind speed. Weather can also be a verb that means to break down rocks.

Weekly Lab

(See Level Pre-A and the SAFETY STICKY NOTE. See also Level B--CHALLENGE.) Provide students with small rocks that they can use to experiment with, finding ways to change the course of the river. Regular dirt works better than "potting soil." Encourage your students to draw pictures to show what they did and what happened.

Math

Answers: 1) 5 hours; 2) 3 hours; 3) 40 hours; and 4) 42 hours

Writing in Science

Ask your students to talk first about what they did and what they saw happen before asking them to write a letter.

Challenge

(See Level B--WEEKLY LAB.) Standard measuring cup and spoons will be sufficient. Make sure your students carefully observe what happens in the jar below. Challenge your students to design an experiment to find something that would slow down the erosion.

Puzzle

Answers: A) 2,000 years;

B) 1,000 years;

C) 2,500 years

DID YOU KNOW??

The Grand Canyon is a example of how water flowing downhill can steadily wear away rock.

Level D

Main Concepts: Rocks weather when they break down. Wind, water, and ice can weather rocks. Erosion occurs when wind, water, and glaciers move the rocks from one place to another. Erosion can have a great impact on people.

Vocabulary

Answer: Definitions should reflect the idea that if rocks or are chipped away and the particles stay put, it is weathering. If the particles start moving, it is erosion.

Weekly Lab

Jolly Ranchers[R] or Starlight Mints candies[R] work well for this activity. See the SAFETY STICKY NOTE on page 1. Form your students into groups of three. Make sure they carefully time how long it takes for each candy "rock" to disappear or "erode away." Relate this activity to the erosion of rocks.

Math

Review with your students what a bar graph is and how to make one.

DID YOU KNOW??

The great dust storms of the 1930s, known as the "Dust Bowl" created great black clouds of dust and topsoil called "black blizzards."

Writing in Science

Encourage students to be creative when writing their reports for the candy company. For example, they may want to address ways they could make their candies last longer. Relate these findings to what they are learning about erosion. For example, which rock would erode faster, one in a fast-moving stream or one in a pond?

Challenge

(See Level Pre-A--WEEKLY LAB and the SAFETY STICKY NOTE.) Have the students try the activity again with a piece of cloth over the soil. Ask them to think how this is connected with nature. Plants work like the cloth in preventing erosion. Some plants, like grass are even called "ground cover." If you have time, consider having students plant grass seed in some of the trays.

Puzzle

Students should divide 460 by 2.5 and then multiply by 13.

Answer: 2,392 tons

Level E

Main Concepts: Chemical weathering changes the chemical nature of the rocks. Mechanical weathering just makes rocks smaller. Erosion occurs when rocks move from one place to another. Erosion is natural, but farmers need to find ways to prevent the loss of valuable topsoil.

Vocabulary

Chemical weathering changes the chemical nature of the rocks. Acid wearing away rocks and rust forming are two examples. Mechanical weathering just makes rocks smaller. Any cause of rocks becoming smaller is mechanical weathering.

Weekly Lab

(For Lab A see Level D and MATERIALS NEEDED on page 1.) For Lab B, students should use the same size piece of steel wool on each lid, for the most accurate results.

Math

Review with your students what a bar graph is and how to make one. Students will need to share their data.

Writing in Science

Students should include as many details as possible. Challenge (See Level A--WEEKLY LAB.) Provide your students with materials that they could use to try to prevent erosion such as rocks, sticks and ground cover cloths. Ask them to try raising and lowering the tray by adjusting the number of books they use. If you have the time, consider having them plant grass seed in some of the trays.

Puzzle

As an alternative to the Dust Bowl, you may choose to have students research flooding caused by Katrina and other recent hurricanes, or mud slides on the U.S. West Coast.

DID YOU KNOW??

The greatest human cause of erosion are: poor agricultural practices, strip mining, removal of forests, and overpopulation.

Weekly Resources

Helpful Sources for Planning Your Science Weekly Classroom Activities

Recommended Resources

* Bailey, Jacqui and Matthew Lilly. Cracking UP, A Story About Erosion. Minneapolis, MN: Picture Window Books, 2003

* Castleman, Virginia. Erosion. Logan, IA: Perfection Learning Corporation, 2004

* Riley, Joelle. Erosion. Minneapolis, MN: Lerner Publications Company, 2007

Internet Resources

http://education.yahoo.com/reference/encyclopedia/entry/erosion

http://teacher.scholastic.com/dirtrep/erosion/invest.htm

http://www.botany.uwc.ac.za/envfacts/facts/erosion.htm

http://www.bright.net/~double/erode.htm

http://www.consrv.ca.go/CGS/information/kids_geozone

http://www.emints.org/ethemes/resources/S00000299.shtml?

http://www.juliantrubin.com/encyclopedia/earthsciences/erosion.html
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Publication:Science Weekly
Geographic Code:1USA
Date:Oct 21, 2008
Words:3420
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