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Earth Is ChangeEarth Is ChangeEarth Is ChangeEarth Is ChangeEarth Is Changemain ideas

backgroundinformation

Earth is in a constant state ofchange. Some changes are cata-clysmic�brought about by the ac-tions of volcanos, earthquakes,floods, landslides, or hurricanes.Some changes are slow andcumulative�brought about by theconstant action of wind and/or wa-ter, the movement of earthwormsor other burrowing creatures, andgrowing plants.

As water flows in brooks,streams, and rivers, it carries alongsand, pebbles, and sometimes boul-ders, that scrape and wear awayrocks and dirt along the way. Wa-ter may also flow into cracks in therocks and freeze. The expandingice may break off pieces of rock.

Wind picks up and throws sandparticles against rocks like asandblaster and slowly erodesthem. Since different kinds of rockshave different surfaces, erosionisn�t consistent in all rocks. But overmillions of years, wind and watercan shape a landscape�just look atthe Grand Canyon! vocabulary: eroding, catastrophic, canyon

PROGRPROGRPROGRPROGRPROGRAMAMAMAMAMSYNOPSISSYNOPSISSYNOPSISSYNOPSISSYNOPSISSCENE 1 Making Changes 1:30A musical introduction illustrates somefast�and not so fast�ways that Earthchanges. As the song says, �Earth ischange�.� because changes of one kindor another are going on all the time.

SCENE 2 Quick-Change Artists :45Cast members Stephanie and Z introduceforces that make quick changes in Earth�ssurface: floods, landslides, hurricanes,erupting volcanos, and soil-shiftingearthquakes.

SCENE 3 The Sands of Time 1:30Some changes to Earth�s surface happenvery slowly over a period of time.Stephanie and Z create a landscape in abox of sand by using a hair dryer to shiftthe sands and show how wind canchange their model Earth.

SCENE 4 Cosmic Clock 2:00How can you see the way Earth changedover millions of years in just a few seconds?Use film to speed things up! An animationshows the changes with the speed of light.

SCENE 5 River Run 2:00Stephanie and Z demonstrate how water canchange a landscape.Moving water carves adeep channel in their landscape and revealsdifferent layers of �rock.� After a while, thekid-made landscape starts to remind Z andStephanie of a certain great canyon!

SCENE 6 Nature�s Canyon 5:00Over millions of years, wind and water woredown Earth�s surface and formed themagnificent landscape known as the GrandCanyon.

� Earth is constantly changing.� Some changes are cataclys-

mic; some are slow andcumulative.

� Wind and water can gradu-ally shape a landscape overmillions of years.

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3-2-1 CL3-2-1 CL3-2-1 CL3-2-1 CL3-2-1 CLAAAAASSSSSSROOM CONTSROOM CONTSROOM CONTSROOM CONTSROOM CONTACTACTACTACTACT LESLESLESLESLESSSSSSON ONEON ONEON ONEON ONEON ONE

BEFORE-VIEWINGBEFORE-VIEWINGBEFORE-VIEWINGBEFORE-VIEWINGBEFORE-VIEWINGDISDISDISDISDISCUSCUSCUSCUSCUSSIONSIONSIONSIONSION

Ask students to imagine that theschool neighborhood had to beevacuated and closed�no one couldlive there or disturb it in any way.What changes would kids see if theycame back to the area in a year?(grass and weeds growing tall; mini-mal changes to buildings and con-crete) What would they find if theycame back after 10 years? (build-ings showing visible wear; crackedpavement) What would have causedthe changes? (wind, rain, ice,heat,etc.) What changes would kids

TUNING INTUNING INTUNING INTUNING INTUNING INAsk if students have heard of any recent news events such asearthquakes, violent storms, mudslides, etc., that have changedEarth�s surface. Discuss any such national or international events,especially any that have changed Earth�s surface in areas kidsare familiar with. Then have students watch the video to find outhow Earth�s surface changes both quickly and slowly.

MATERIALS:� plastic window box� watering can� water� plastic tablecloth or

shower curtain� 2 bricks� large dishpan� 5-gal. bucket of sand

AFTER-VIEWINGAFTER-VIEWINGAFTER-VIEWINGAFTER-VIEWINGAFTER-VIEWINGACTIVITYACTIVITYACTIVITYACTIVITYACTIVITY

WHA WHA WHA WHA WHAT TO DOT TO DOT TO DOT TO DOT TO DO:::::1. Cover a desk with the plastic

cloth/curtain.2. Spread sand evenly in the bot-

tom of the box. Put it on thedesk with one end up on a brickand the other in the dishpan.

3. Let student sprinkle water at thehigh end of the box. The simu-lated rain will form streams asit pushes and carries sanddownhill. Soon there will be awell-defined channel.

4. Smooth out the sand. Put 2 bricksunder the end of the box. Repeatthe experiment but take the sprin-kler head off the watering can sowater can pour out full force. Askhow this channel differs from thefirst one. (deeper and straighter)Why? (Water had more force tocut through sand.)

5. Reset the box on one brick. Burythe other brick under sand in themiddle of the box. Have a stu-dent replace the sprinkler headand start the simulated rain. Whathappens? (Water flows aroundbrick; uncovers brick.) Explainthat erosion is making a �moun-tain� appear! The brick materialis held together tighter than thesand, so it resists erosion.

find after 100 years?(crumblingbuildings; broken concrete)

Discuss the idea that Earth�s sur-face is constantly changing: wind,rain, ice, and heat break it down;moving water in rivers and streamswears it away, or erodes it. Mostchanges happen so slowly thatpeople may not notice. How do kidsthink Earth�s surface might bechanged very, very quickly? (byflood, earthquake, erupting volcano,hurricane, etc.) Remind your studentsthat depending upon where you livesome periodic catastrophic eventscan change Earth�s surface in yourarea.

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PURPOSETo demonstrate howdifferent types of rockswithstand erosion.

MATERIALS:(per 5 students)� an empty 1-lb coffee can with

lid� 2 small chips of marble (from

garden supply store)� 2 small quartz pebbles� 2 small pieces of concrete block

or brick� 2 small pieces of coal or soft

rock (talc or calcite)� metric ruler� 1 cup of water� 5 pencils

WHAWHAWHAWHAWHAT TO DOT TO DOT TO DOT TO DOT TO DO:::::1. Divide the class into groups of 5, then

distribute materials and copies of theactivity sheet, �Shake, Roll, andRattle!� Identify the 4 types of rocksyou have for your students. (If youuse a rock different from one listedunder materials, be sure to �white out�the rock-name on the activity sheetand insert the proper rock-name.)

2. Have kids measure each rock acrossits widest part. Ask each group mem-ber to record that data, plus a fewwords to describe each rock (smoothand round, sharp and flat, etc.) on theactivity sheet.

3. Ask each group to put the rocks inthe can, add the water, then snap onthe lid. Explain that students willsimulate changes to Earth�s surfaceby shaking the rocks and water as ifwind, water, and movement were erod-ing them over time. But first, ask kidsto predict which rock will wear downthe most and which will change theleast; then record predictions on theiractivity sheets.

4. Ask one person in each group to shakethe can. Remind kids to keepone hand on the lid to prevent it fromflying off.After one minute, call,�Switch!� Then another person in eachgroup shakes the can. Continueswitching until every group membershakes the can for one minute�a totalof 5 minutes.

5. Have kids remove the rocks, examinethem, re-measure them, and describethem on the activity sheets. Circle con-clusions. Which shows the most wear?(coal) The least? (quartz) What else dokids notice about the rocks? (somerounder; pieces smaller; more piecesthan before)

What do kids think might happen if the rockswere returned to the cans and shaken for 5 min-utes more? 10 minutes more? Why do peopleuse granite, made chiefly of quartz, for monu-ments instead of coal? (granite resists weather-ing; coal wears down fast)

CURRICULUMCURRICULUMCURRICULUMCURRICULUMCURRICULUMCONNECTIONSCONNECTIONSCONNECTIONSCONNECTIONSCONNECTIONS

Help kids understand how the action of wind andwater can affect a neighborhood. Take them on atour to observe any old stone buildings or stonestatues in the neighborhood. Find out from cor-nerstones and/or dedication plaques when each wasbuilt. Look for cracks in and water marks on thestones. Compare the conditions of recently builtbuildings and recently erected statues to those

that have been around for a very long time.How has the condition of each stone objectchanged? What things might have causedquick damage to the objects? (floods, violentwindstorms, ice, etc.) What forces might havecaused changes over long periods of time?(heat, wind, ice, etc.)

SOCIALIF STUDIES

LESLESLESLESLESSSSSSON TWOON TWOON TWOON TWOON TWO 3-2-1 CL3-2-1 CL3-2-1 CL3-2-1 CL3-2-1 CLAAAAASSSSSSROOM CONTSROOM CONTSROOM CONTSROOM CONTSROOM CONTACTACTACTACTACT

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3-2-1 CLASSROOM CONTACT© 1993 Children�s Television Workshop

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