DOCUMENT RESUME

ED 103 248 SE 018 529

TITLE ShLiows, An Environmental Investigation.INSTITUTION Minnesota Environmental Sciences Foundation, Inc.

Minneapolis.; National Wildlife Federation,Washington, D. C.

PUB DATE 71NOTE 17p.; Related documents are SE 018 514-534AVAILABLE FROM National Wildlife Federation, 1412 16th Street, N.V.

Washington, D.C. 20036 (Order No. 79034, $1.00)

EDRS PRICE NF-$0.76 HC-$1.58 PLUS POSTAGEDESCRIPTORS *Ecology; Elementary Educat:I.or; Elementary Grades;

*Environmental Education; Instructional Materials;Investigations; *Learning Activities; *Light; NaturalResources; *Science Education; Teaching Guides

IDENTIFIERS *Shadows

!BSTPACTThis environmental unit is one of a series designed

for integration within an existing curriculum. The units aroself-contained and require minimal teacher preparation. Thephilosophy bekind the units is based on an experience-orientedprocess that encourages self-paced independent work. This unit onshadows is designed for all elementary levels, grades 1-8. Theactivities become progressively more sophisticated, making some moresuitable at different levels. In the first section, the goal is forstudents to explore the concept of spatial relationships through playactivities with shadows. The games include shadow tag and keep away,shadow plays, and mystery shadows. The activities of the secondsection are concerned with shadows caused by sun and earth movements,and with the effects of shade on the life of plants and animals.Activities include studying the passage of time as indicated byshadows, determining the height of a pole by shadow calculations, andinvestigating the effects.of shade on green plants. Each activity inthe unit includes a list of materials needed, directions, andquestions for discussion. (NA)

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u 'ARTMENTO1l Heal THEDUCATION A WELFARENATIONAL INSTITUTE OF

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John Cary Stone

Nat. Wildlife Fed.,Q EPIC AND ORGANIZATION, OPERATINGUNDER AGREEMENTS WITH THE NATIONAL IN-

STITUTE OF EDUCATION FURTHER REPRO-DUCTION OUTsIDC THE EPIC SYSTEM RE-MIRES PERMISSION OF THE COPYRIGHT

OWNER

THE ENVIRONMENTAL UNITSone 0! a ,!,,,a1` itt l-nvnonmi, roai t 'nits written by the Inwironmental t. (. 2enter And 1110,11.11yd by the

1\':1.1hte I uthTation

In both Oleo!\ and plat tit e education is he essential base for tong-range lot al, regional and national programs

11111t10% ,inn 11,01nt.11: Aoilmen: net essarY 101 Man's, ItalUC atlel skit VIVA. pis't'il'. :Mist be aware

oi et oloc,n vs in older to 'et appreki,!te and tultill tonstrut nye roles in society. I his atvareness

heti the existing k.klut ational plot es, 111 klassroom and tatted school aktivities. No spet la!

out ses on et olog\ tan repiat e the net" I :0 integrate et ologik al learning throughout the existing curricula ot our school

s. terns I M t hut mote, the litestvles a Id value -systems nuke...try for ration.d environmental decisions 1.1x1 hest he

at ttl;:t eta tut-waled exposure to et ologat al !eat nine; which pervades !he total edukational experience

It t \ as thoughts that we developed these curriculum materials. hey were designed for the classroom

te... her to c, e oith a minimal amount of preparation. They are meant t be part ot the existing curriculum to com-

plement and enhant e what sladellls .1r.` already experiencing. Each unit is komplett. in itself, containing easy-to-tollow

desk no It qls its 0/let II yes And methods, as t.e11 as lists ot simple materials.

1 he untied\ mg philosophy throughout these units is that learning about the environment is not a memorization

process, but rather an expu rienceonentud. experiment-observation-conclusion sort of learning. We are confident that

students at all levels will arrive at intelligent ecological conclusions it given the proper opportunities to do so. and it

not touted into -right- answers and precisely "accurate- names for their observations. It tollowed in principle by the

teak her the..t. units will result in meaningful environmental education.

In the prok ess ot development. these units have been used and tested by classroom teachers. atter which thee have

undergone e\ aluations, revisions and adaptations. Further constructive comments trorn classroom teachers are en-

ouraged in the hope that we may make even more improvements.

A hst of units in this group appears on the inside back cover.

About the National Wildlife Federation-1412 Sixteenth Street, NAV., Washington, D.C. 20036

Ft untied in 103o. the National Wildlite Federation has the largest membership of any conservation organization in

the world and has attiliated groups in each ot the 50 states, Guam, and the Virgin Islands. It is a non-profit, non-

governmental organization devoted to the improvement ot the environment and proper use of all natural resources.

NWF distributes almost one million copies ot tree and inexpensive educational materials each year to youngsters. edu-

cators and concerned citizens. Educational activities are financed through contributions for Wildlife Conservation

Stamps.

At it the Environmental Science Center-5400 Glenwood Avenue, Minneapolis, Minnesota 5522

The Environmental Science Center, established in 1007 under Title III of the Elementary and Secondary Education

Act is now the environmental education unit of the. Minnesota Environmental Sciences Foundation. Inc. The Center

works toward the establishment ot environmental equilibrium through educationeducation in a fashion that will

develop a conscience which guide:, man in making rational judgments regarding the environmental consequences of

his acti.:ns. To this !.nd the Environmental Science Center is continuing to develop and test a wide variety of instruc-

tional materials and programs for adults who work with youngsters.

ShadowsAn Environmental investigation

BY

NATIONAL WILDLIFE FEDERATION

MINNESOTA ENVIRONMENTAL SCIENCES FOUNDATION, INC,

Design and Illustrations byJAN BLYLER

When children explore shadows they are experimentingwith spatial relationships. Enabling students to discern spa-tial relationships is the goal throughout the play activities ofShadows.

The unit also has a very direct application to ecology inthat shade affects living things. The children will investigatethis effect late in the unit by examining the difference innumbers and types of plants in shaded and sunny areas. Stu-dents will find that shading from sunlight has an importanteffect on the ecology of an area.

The objectives of this unit, therefore, are simple butcritical. We hope that early primary school children will:

1) explore shadows and experiment with spatial rela-tionships, and

2) understand that shadows change according to theposition of the light source.

The second and third sections of this unit are probablymore appropriate for grades five through eight. The goal forthese late primary school children is that they:

1) learn about sun and earth movement by investigatingshadows, and

2) understand the effects of shade on the life of plantsand animals.

Table of Contents

Introduction 3

Materials 3

Playful Shadows 4

I Outdoors 4

Shadow Tag 4

Shadow Keep Away 4

Shadow, How Many Shapes Do You Have? 4

Shadow People 5

II. Indoors 5

Your Hands Can Make Strange Shadows 5

Stage a Shadow Play 5

Mystery Objects 6

Shadows Which Answer Questions 6

I. Shadow, What Time Is It" 6

II. Shadow, in What Direction Am I Pointing? 9

III. Shadow, How Tali s the Flagpole? 10

IV. Shadow, What Time Is It in England?

Preliminary Activities iiDetermining the Time in Other Countries

Shadows Which Affect Living Things 12

0 1971by National Wildlife Federation

INTRODUCTION

The unit begins with a series of play activities, some indoors, someoutdoors, which give the younger children or beginners an understandingof the nature of shadows. The students will find that shadows are causedby a light source and an object which blocks the light from that source.They will see that the size and shape of the shadow depends upon thelocation of the light source in relation to the object. These are essen-tial concepts for a child to grasp before developing more sophisticatedunderstandings of shadows. The "larger" concepts will also be investi-gated, in later activities of this unit.

It is important for children to discover that shadows are predictable.The children will find they can predict the length and direction of ashadow at certain times of the day, and at different times of the year.This not only gives them a feel for patterns in nature but also generatesan understanding of earth and sun movement. For example, they willsee why a noon shadow is always shorter than one at any other time, andwhy a noon shadow in the northern hemisphere always points north. Thechildren must begin to recognize the movement of the earth in relationto the sun, to account for these happenings. To help make this associa-tion they will make use of a globe and a lamp.

large objectswith simple outlines

chalkpavementbed sheetslamp with 150-200

watt, clear light bulbtapewhite paper

MATERIALS

tablecoat hangersbag or boxstationary objectcardboardstakescrayonsworld globesclay

yardsticksclipboardsflagpoletoothpicksmap of time zonespinsstick figuresstringcompasses

ShadowsPLAYFUL SHADOWS

Some fun games to play can also be learning ex-periences of significance. The following examples aredesigned to acquaint the children with shadows andhow they function. The concepts are simple, but willprobably be better grasped by the children if dis-covered through playing games.

I. OutdoorsA. Shadow tag

1. The person who is "it" tries to touch his shadowto another player's shadow,

or2. The person who is "it" tries to step on another

player's shadow.In either version 1 or 2, use a stationary shadow(from a building, tree, etc 1 as a safety place.

B. Shadow keep awayAsk the class to stay within a limited area (tennis

court, etc.). Have each child choose a partner whowill try to step on his shadow. The object of the gameis to prevent this from happening. When it does hap-pen, the partners can switch roles ("hunter" becomes"hunted").

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C. Shadow. how many shapes do you have?

1. Have each child bring to school a lerge, lightobject with a simple outline. (For example,garbage can covers, hoola hoops, umbrellas,brooms, inner tubes, cardboard boxes, etc.)

2. Divide the class into teams of two childreneach, provide each team with chalk, and havethe teams spread out over a parking tot or someother paved area.

3. One child manipulates one of the objects andthe other child sketches the outline of hisshadow on the pavement with chalk.

4. Ask the children how many different shapesthey can make with the shadows of their objects.a. How large or small can they make the ob-

ject's shadow?b. How skinny or fat can they make the object's

shadow?c. How dark and crisp can they make the ob-

ject's shadow?d. How faded and fuzzy can they make the ob-

ject's shadcw?

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D. Shadow people

I. Have each team of two children make sketcher.,

of the shadows of their own booies white theyassume different positions. Team members cansake turns being the person who outlines theshadows with chalk. Can they make monsterpeople? Can they make a shadow with theirbody which doesn't look like a person at all?

2. Make groups of four children each by pairingup the teams. Ask the team members to taketurns being the person who outlines the shad-ows with chalk. The other three children shouldconstruct some design or picture using theirshadows. Can they make an unusual design thatdoesn't look like three children? Can they makean animal like a giraffe or maybe make up anew animal out of their imagination? Can threepeople. stand in a line so the shadow looks likeonly one person?

110 Indoors

A. Your ham' 'In make strange shadows1. Set a 200 watt lamp, without a shade, in

the cei,,cr of the room. Have each team tape a3' x 3' piece of white paper on the wall.

2. Shut off all lights but the one in the center ofthe room. Draw the blinds and ask the teams tocreate designs. animals. etc., on the white

paper.3. As each team member creates a new design,

the other member can sketch around the shadowon the paper.

B. Stage a shadow play1. Build a stage by hanging a sheet in a doorway

or on a frame. Put a strong light source behindit (slide projector or lamps).

2. Have each team think of some kind of activitythey can perform behind the screen. Here are

some suggestions:

BoxingTwo children stand behind the screen,one closer to the sheet than the other, forsafety. Both childrea then make boxing ges-tures. Since the shadows both fall on the samescreen, it locks like they are facing one another.

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An Operation I he "doctor" removes books.pencils, etc. from the "patient." (Have the children figure out how to do this for themselves.)

3. Put a table behind the screen and have the chil-dren create and perform their own dramas us-ing cutout figures, or small figurines and play.things from home. The figures could be tapedor glued to handles made out of coat hangers.These plays might be taken from their readingbook or might relate to some other subject theyare studying, such as social studies. Place thelight source on one side of the stage so thatthe shadows of the children's bodies are lessapt to show Do they realize that the closer theyhold their characters to the screen, the sharperand darker are the shadows which their audi-ence sees?

C. Mystery objects1. Have the children bring a "mystery object"

from home, concealed in a bag or box, it shouldbe some common household object. Have eachchild draw a numbLr from a hat the day before,and tape his number to his object. The childrenshould keep their numbers secret for the timebeing.

2. Each child uses his mystery object to cast fourdifferent shadows on the sheet of the shadowstage. One bottle, for example, might cast allthe following shadows:

The rest of the class writes down the child's name andmakes notes or drawings of the shadows.

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3. After projectinc its shadow, each chi's depositshis mystery object in a box, takini, care thatthe class cannot see it. The teacher holds acloth over the box so that no one can see theother mystery objects which the box contains.

4. After all the members of the class have had achance to project the shadows of their objectson the screen, the teacher displays all the mate-rials on a table.

5. The children look at the objects and try tomatch each one with its owner, by writing thenumber of the object next P. the name of thechild they think owns it.

6. After a few minutes, the teacher can go overeach object and ask who showed it. Some stu-dents may have had problems with certain ob-jects. The class can discuss why the shadowsof some may have been harder to guess thanothers.

As an alternative, each child can bring in two orthree objects which the teacher will collect and num-ber. The mystery pieces should then be doled out,one per child. The advantage here is that the teachercan sort out the types of objects which are used, withan eye toward greater variety. She could also limit theselection to one type of object, such as bottle ifcircumstances make this desirable.

SHADOWS WHICH ANSWER QUESTIONS

I. Shadow, what thus Is It?

A. Have the class observe that a st.adow from the sunchanges position with the time of day. Rememberto make allowances for daylight saving time, espe-cially for the sun clock activity in section C whichfollows. It is best to be consistentuse the sametime system throughout the year or the childrenwill be misled about the time of the shortestshadow.

1. Have each team select and study the shadowmovement of one or two objects:a. Have a team member use chalk to mark the

movement of the shadow of the school build-ing once every two hours during the day.

b. Have each child stand in a separate spot andmark the position o; his feet by drawing

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around them with chalk Then have the ste.dents mark the change in length of their ownshadows from that position. once every twohours during the day.

c. I-;ave team members mark the change inlength of the shadow of some small stationary object such as a twig.

2. To predict where p shadow will fall, have eachteam select and study the shadow of an objectas in part A.1 above. After marling the shad-ow's position twice, have them predict whereit will fall in two hours. After the two hours,see how close each student cane with his pre-diction.

B. Have the class mark the change of a shadow'sposition over a period of time.1. Does a shadow change positions from one day

to the next?a. Put a mark, maybe an "X," on the window

with tape. During the time of day that the sunshines on the window, the "X" will 'ast ashadow on the floor. Over a period of timethe class will be marking numerous "X's" onthe floor to record shadow changes. To pre-vent excessive confusion from the variousmarkings, you may want to experiment withthe best size for the "X" on the window. Forexample, you probably will not want theshadow too large.

b. Assign each team a time of day to mark theshadow's position. Have the students usetape to mark this shadow position on thefloor. Perhaps various teams could check itevery half hour. Remember the window willonly be in the sun part of the day.

c. Have the teams write the date and time ofday on each "X" put on the floor.

d. They should c8 tech the next day to see if theshadow falls on the same spot at the sametime. If not, have them put down more tapemarks showing its new position.

2. Does the shadow change position from oneweek to the next?a. A week later check the shadow position at

the same time of day used the week before.If the shadow was checked on Monday at12:30. 1:00, 1:30, 2:00, and 2:30, for ex-ample, check the shadow at those times thenext Monday.

b. If the shadow does not fall on the "X's"taped to the floor the week before, have theteams make new "X's" showing the shadow'snew position for the time of day. The chil-dren may want to color the tapes for differenttimes and different days,

c. Have the children write the time of day anddate on each new "X."

3. Does the shadow change position from onemonth to the next?a. A month later, check the shadow positions at

the same times of day used the monthearlier.

b. If the shadows do not fall on the "X's" tapedto the floor during the previous month, havethe students make new "X's" showing eachshadow's new position for that time of day.

c. Have the children write the date and time ofday on each taped "X."

d. Have each team keep a record of the tapeposition, date, and time, on a map or chartin a notebook, in case the tape Is accidentallyremoved or worn off.

4. Check each succeeding month the same way.Give the class a chance to predict where theshadows will fall each month. Perhaps youcould keep account of the closest prediction foreach month. Select just one hour, for example1:00, for the students to make their predictions.

During the month of May, the northern hemi-sphere is approaching its closest point to thesun for the school year. June 22, the summersolstice, is the actual day that the northernhemisphere is closest to the sun. December 22,the winter solstice, is the day it is furthest fromthe sun.

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For this experiment. suppose you choose totake shadow readings during the first half ofDecember and the last half of May. This shouldaccommodate Christmas vacations in Decemberand summer vacations in June. The May experi-ments could be adjusted to tha first part of May,as your schedule demands, but the closer toJune 22, the better.

In December. the northern hemisphere istilted away from the sun, and the angles thatthe sun's rays make with the earth are the mostoblique they will be all year. This means thatthe rays are their most indirect, and will createrelatively long shadows. By contrast, the anglesof the sun's rays in May are more direct, mak-ing shorter shadows.

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IOSCEMBE R

If you measure the shadow of a stick in theground every day at noon in the first half ofDecember, and then do the same in the last halfof May. (December will be eastern standardtimeremember to adjust for daylight savingtime in May), you should find that the Decembershadows are, generally, longer than the Mayshadows.

5. At some time during the shadow unit, divide theclass into groups and have them try to accountfor the change in a shadow's position over aperiod of time. To do this they will have to con-sider the earth's movement in relation to thesun. Such a discussion might be held during thefollowing activity. "Shadow what time is it inEngland?" which deals with the same subject.

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An alternative would be to line the children up out.doors and take a picture of them and their shadoweach month. These pictures must be taken in as closeto one-month intervals as interfering weekends w:alallow. They also must be taken at the same time ofday and in the same position each month. Label thepictures with the dates, and tape them side by sideon the bulletin board. Have the class note the differ.ences in shadow length and direction from month tomonth.C. Have the cla:s make a sun clock (see the earlier

note regarding daylight saving time).1. Ask a child from each team to bring a large

sheet of cardboard to school (approximately 3'x 3'). Provide each team with a stake approxi-mately 11/2 feet tall and about 1/2" to 1" thick.

2. Have the children lay the cardboard on theground and drive the stake vertically throughthe center of the cardboard into the ground.They should leave about a foot of the stakeabove the ground, and then fasten the cornersof the cardboard with small stakes.

3. Each team should outline the shadow of thecenter stake for every hour of the school day.You might assign each team an hour to put amark showing the end of that hour's shadowon the sundials. In other words, when the hourarrives one team could go outside and mark theshadows for all the teams. The children shouldlabel their marks with the hour of the day(11:00, 12:00, 1:00, etc.).

4. When the hours are all marked, ask the chil-dren if they can tell where the shadow will fallon the half hour. If they can, have them maketheir marks and see if they were right. If not,they could check to see where the shadow ac-tually falls on the half hour. Ask if they can now

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tiLiki, Mal 10, on their mindial to show where theshadows will till every 15 minutes.

Ask them to make the mark designating halfhours a different type than the mark for hoursThe 15-minute marks should also be differentfrom the others.

IL Shadow, in what directionam I pointing?

A. Break the class into teams with, say, two childrento a team, four teams to a group. Provide eachgroup (4 teams. 8 children) with a lamp. For sharpshadows use a 150watt clear bulb. Give each teama globe (of possibleif not, use one globe and stagger the shifts of teams which use it at a giventome), a oneinch high stick or cardboard figure, alump of clay, and a 10foot piece of string.

B. Have the teams push the stick or figure into theclay lump and press the clay onto the globe in thearea of the school or home.

C. Using the 10.foot piece of string as a guide, haveeach team place its globe 10 feet from the lamp.The lamp should be kept at the same level as theequator of the globes, with the north pole up.

D. Have the teams rotate the globe so that there is ashadow cast by the stick. Now imagine that theearth is spinning as it actually does while theteams turn the globe slowly in a westto-east direc-tior (counter-clockwise as you look down at theglobe). What happens to the shadow?

On most plobes. the stock will probably not passunder the arm or ring that holds the globe in place.Therefore, the children will have to turn the globeas far as it will Ro in a clockwise direction and thengo back in the other direction (counterclockwise),in order to simulate a complete rotation.

E. Have groups of about tour students each discussthe information gathered and relate the informa-tion to their previous studies about the changes ofthe sun's shadow throughout the day. They mightconsider such uuestions as:

a. Where is the stick in relation to the lamp whenits shadow is longest?

b. About what time is it when the sun shadows arelongest?

a. Where is the stick in relation to the lamp whenits shadow is shortest?

b. About what time is it when the sun shadows areshortest?

a. Where does the stick go into darkness (noshadow)?

b. About what time is it when sun shadows dis-appear?

a. Where does the stick come into light (shadowbegins)?

b. About what time is it when sun shadows appearagain?

F. Initiate a class discussion, raising the followingquestions only it the class does not:1. How many times does the earth spin around in

a day? (One turn of the globe moved the teams'figures from light to dark.)

2. About what time of the day is it when a shadowis its shortest? (Relate these questions to thesetup of the light and globe.)

3. Return to the globe-lamp setup. In what direc-tion does the shadow point when it is shortest?(The answer is north, though this would not betrue in the southern hemisphere. The classprobably will not know that the sun stays in oneband around the equator of the earth and itmay be too difficult a problem to tackle at thistime.)

G. Try this activity outside: Have teams put a stakein the ground and mark the length and direction ofits shadow. Use small stakes at the end of theshadow, and put one stake in the ground every 10minutes from 11:30 to 12:30. Each team might beass.igned a time at which it will be responsible forgoing outdoors and marking all the teams' shadowlengths. Based on this information from the shad-ows, which of the stakes signifies it is noon? Basedon this information, what direction is north? (Theshadow is shortest about noon and it will point

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north.) If possible. you might check north with amagnetic compass itie students have now Lon,strutted a shadow compass and from this shouldbe able to tell the direction of south, west, andeast. as well as north.

s

III. Shadow, how tall is theflagpole?

A. Provide each team with two yardsticks (or oneyardstick and string), and clipboards.

B. Let each team select an object whose height canbe measured directly. (For example, they maychoose a pole used as a support for a volleyballnet.)

C. Using the yardstick, have them measure the lengthof the pole's shadow and record it. (Do not meas-ure the height of the or -ject at this time.)

D. Holding one yardstick t>a-aight up, measure thelength of that yardstick's shadow by using thesecond yardstick,

orcut a length of string the same length as the shad-ow of the yardstick and measure the string. Howmany times does the shadow string fit on the yard-stick? if the shadow string is longer than the yard-stick, how many times does the yardstick fit on thestring?

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E. The shadow of the pole measured earlier shouldfit on the pole the same number of times as theshadow of the yardstick fit on the yardstick. (Anobject and its shadow are at right angles to eachother. They comprise two sides of an imaginaryright triangle which would be formed by a lineconnecting the top of the object with the end-pointof the shadow. This method of determining thelength of an object is based upon the theorem thatcorresponding sides of similar right triangles areproportional.) For example, suppose the shadowof the yardstick (as designated by the length of theshadow string) fits on the yardstick two times;then the shadow of the pole will fit on the poletwo times. Thus, if the length of the pole's shadowis one yardstick long, the height of the pole is twotimes one yardstick, or two yardsticks tall. (Usefractions any way your class can handle them. Youmight ignore fractions altogether. Or, you mightconsider 1/2 or more equal to "1" and less than 1/2as "0.")

F. Each team then measures the actual height of thepole (or whatever object it chose), and comparesthis with the height which was calculated by usingshadows.

G. Use this procedure to find the height of objects tootall to measure directlyfor example, buildings orflagpolesby measuring the shadow and dividingby two (or whatever number signifies the numberof times that the shadow string fit on the yard-stick).

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IV. Shadow, what time is it inEngland?

For this activity, it will be necessary for the chit.dren to recognize the north and south poles of theglobe. They will make use of the shadow compassthey built earlier, and the technique of determiningshadow proportions used in "Shadow, how tall is theflagpole?"A. Preliminary activities

1. Let the children practice telling directions onthe globe (east and west, north pole. southpole).

2. Let them practice using their shadow compass.3. Have each child measure the length of his own

shadow outdoors and then cut a piece of stringthe same length as his shadow. Each childshould then have a friend measure his height,and cut a string of this length also. Then askeach child to compare the length of the stringfor his shadow with his actual height. Depend-ing upon which is longer, how many times doesthe shadow string fit on the height string or howmany times does the height string fit on theshadow string? If your riass has not used frac-tions, count less than half a length as "0" andmore than half a length as "1."

Using a toothpick stuck in clay and placed on atable top. have each child move a lamp around Lotilhe can get the same relationship between the tooth-pick and its shadow as he did between himself andhis shadow. (The students may want to refer to theirwork in, "Shadow. how tall is the flagpole?"). Forexample, if the shadow string is 21/2 times as long asthe height string, make the toothpick shadow 21/2times as 'ong as the height of the toothpick by mov-ing the lamp. Try this (that is. measuring each child'sshadow and height proportion. and making the tooth-pick and lamp setup correspond). at several differenttimes during the day (morning and afternoon), untileveryone is capable of doing it. In a discussion, bringout the fact that the angle of the light from the lamphitting the toothpick approximates the angle that thesun's rays make with the child.

The direction in which the shadow is pointing willalso be important in subsequent activities. See if thechildren can place the light source so that the tooth-pick shadow is pointing in the same direction as theirshadows were pointing outside.

B. Determining the time in ether countries

1. Go outside with the class. Pair off the studentsand have one child stand still while his team-mate measures the length of his shadow. Then,using the shadow compass, have the teammatedetermine the direction the shadow is pointing.Make determinations at 8:30, 10:30, 12:30,and 2:30.

2. Compare the length of the shadow to the heightof the student, as in the preceding ;11ustration.

3. As in part II of this section. set up lamps andglobes wth 10-foot distances between them.Have the lamps at the sama level as the equatoron the globes.

4. If only one globe is available, assign each teama time when they can use the globe and light,to work steps 5 through 11.

5. Using a one-inch figure. have the children stickit on the globe with clay in the location of theirhome or school.

6. Have the children move the globe so that theshadow cast by the one-inch figure is in thesame proportion and direction as their ownshadow was cast at 8:30. Fix the globe in thatposition.

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7. Place a second one inch figure on the globe.Position it on a line which runs from west toeast though the 8:30 figure.

8. Look at the shadow length and direction of thesecond figure. Judging from the informationthe children have on their own shadows at8:30, 10:30. 12:30. and 2:30. ask what theapproximate time of day is in the spot wherethis second figure is located. Can they move itaround so it is at the point on the globe whereit is about 10:30?

9. Using a third figure have the children locateit on a line extending to the east of the 10:30figure. Judging from the information they havegathered on their own shados, ask what theapproximate time of day is in the spot wherethe third shadow is located. Can they move thefigure so it is at the point on the globe where itis exactly 12:30?

10. Have the children go through the same proce-dure with a fourth figure and locate it at a 2:30position.

11. Rotate the globe from west to east (counter-clockwise) until the figure with the 10:30 shad-ow has an 8:30 shadow. What happened to thefigure which originally had the 8:30 shadow?What time do the children think it is where theirfirst figure now is? What happened to the otherfigures?

12. Each team should write down where it locatedthe sticks on the globe for each of the times.Obtain a map of the time zones and let themcheck to see how close they came.

SHADOWS WHICH AFFECT LIVING THINGS

The children will compare the number of speci-mens of a kind of plant in an area that is shadedmost of the day, with the number of specimens ofthat kind of plant found in a sunny area.A. Take the class outdoors to a part of the lawn which

is not shaded by buildings, trees, or other objects.B. Provide each team with a yardstick, four stakes,

and about four feet of twine. With this materialthey will rope off one-foot-square plots. (Or, use awire hoop tossed on the ground to delineate anarea.)

C. Have each team use the stakes and string to ropeoff a plot one foot on each side, in an area that issunny most of the day.

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BEST COPY AVARABLE

D. Each team may now examine its plot for differentkinds of plants. Have each team pick one planteach, of the three most abundant kinds of pldlitsin their plots, and pin them to a centrally 1..)catedpiece of cardboard.

E. From this collection, select a kind of plant which isfound in all or most of the plots. Have each teamcount the number of specimens of that plant in itsplot.

F. Have the teams select other plots in an area whichis shaded most of the day but which also has vege-tation. (Next to a building?) Have the studentscarefully count and record the number of speci-mens of the selected plant in their own plots whichare also found in this shaded area.

G. Return to the classroom and have each group oftwo or more teams combine data. Can they see anysignificant differences between the sunny andshaded areas? Take an average for the class of thenumber of selected plants per plot in the shadeand compare it with the average number per plotin sunlight. (They could compare the total numberif they cannot do averages.) Is there a significantdifference? Does shade seem to have a good or abad effect on this plant's growth?Important Note: Don't change the type of area

when changing from a sunny plot to a shaded plot.Otherwise you may introduce variables other thanamount of sunlight. For example, the type of soil maybe different. If you are studying sunny plots on theschool lawn, try to stay on the school lawn to studyshady plots.

Ask the children about shade and its effects uponother things in the environment. Ask if shade isnecessary. How does shade from some plants affectother plants? How might that affect animals? Whathappens to plants and animals when there is com-plete shade (nighttime)?

If the class displays enough enthusiasm, you maywant to supplement this unit with Differences in Liv-ing Things or Vacant Lot Studies, both of which arerelated units in this series.

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THE ENVIRONMENTAL UNITS

Below is a list of the first titles in the Environmental Discovery Series.The ones with order numbers next to them are available as of August, 1972.The others are in preparation and will be available in the coming weeks.Also, ten additional units will be announced soon.

Next to the titles, we have suggested the graucs for which each is mostappropriate. We emphasize that these are suggested grade levels. Theteacher is encouraged to adapt the activities to a wide range of grade levels,and subject areas depending upon the interests and abilities of the students.

OrderNo. Title

GradeLevel Price

OrderNo. Title

70007 Plants in ttit: Classroom 3-6 $1.50 70123 Genetic Variation

70016 Vacant Let Studies 5 -9 1.50 70132 Soil

70025 Differences in Living Things 4-8 1.00 79141 Tile Patterns and Graphs

79034 Shadows 1-8 1.00 79150 Plant Puzzles

70043 Wind 3-6 1.50 70169 Brine Shrim) and Their Habitat

70052 Snow and Ice 1 -b 1.50 70178 Nature's Part in Art

79061 Man's Habitat The City 4-9 1.50 79212 Contour Mapping

79070 Fish and Water Temperature 4-9 1.50 Change in a Small Ecosystem

70080 Oaks, Acorns, Climate and Squirrels 1-8 1.50 Transect Studies

79105 Nature Hunt Spec. Ed. K, 1 1.00 Stream Profiles

79098 Sampling Button Populations 3-9 100 Color and Cha-)ge

79114 The Rise and Fall of a Yeast Community 6-9 1.00 Outdoor Fun for Students

if you would like a free brochure describing activities in the individual units, write:

The National Wildlife FederationEducational Servicing1412 16th Street, N.W.

V6shington, O. C. 20038

GradeLevel Price

4-9 1.50

2-9 51.50

1-2 1.00

1-6 1.50

1-5 1.50

3-6 1.50

4-9 1.50

5-9

Written and developed by:

NWF MESF Karen JostadJohn Cary Stone Edmund Bray Edward LandinJames D. Davis Barbara Clan Richard MyshakWendy Kay Robert Collins Michael NaylonPhil Nicholson Joann Current Robert O'HaraTom L. Smith John Heitkamp Noreen Teachout

David Jones Carl Vogt

3-0

4-9

K-2

1-12

NATIONAL WILDLIFE FEDERATION1412 Sixteenth Street. N.W.Washington, D.C. 20036

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