MOTIVATION IN GEOGRAPHY 489

FOUR UNITS TO ILLUSTRATE MOTIVATION IN THETEACHING OF GEOGRAPHY: PART IV.

BY ALICE J. HAHN,Proviso High School, Maywood, III.

The last unit which I chose to present is taken from thaton Temperature. There are, of course, several factorswhich help to determine the temperature of a region, amongwhich distance from equator, altitude, and winds and oceancurrents are all very important. Each of these is taken upin turn, the first one to be studied being that of distancefrom equator. We all know that temperatures do not varyconsistently as does the sun or else every place on the sameline of latitude would have exactly the same average tem-perature, which is not so. But the position of the sun inthe sky for different places in the same latitude does notvary, i. e. the sun is exactly as high in the sky at noon inChicago as it is at any other place having the same latitude,when it is noon there. Since the position of the sun in thesky and the length of time it shines play a very importantpart in determining the temperature of a certain area, thechildren are taught to draw what we call sun-shadows forevery line of latitude 10 degrees apart. They are also giventables which will help them in determining the length oftime that the sun shines between sunrise and sunset. Thedrawings which are made show not only the position of thesun in the sky at noon, but also the length of the shadowcast. In order to make sure that the children understandthese, they are given help in working out several together,the directions for which are given in the unit. Let us readthe instructions for the first one together:

(1) The Equator. Draw a line around your protractormaking a semi-circle to represent the heavens. Let the ob-ject which is to cast the shadow be ^ inch high, and placeit directly below the zenith. Now suppose that you areon the Equator on March 21st. Where is the sun shiningdown directly at noon on that date? (The answer, ofcourse, is on the Equator.) Where then would you lookto see the sun? (We see that it would be directly overhead.)Locate it with a dot on the semi-circle. Would there be anyshadow? (And, of course, there would not.) (2) Nowsuppose that the date is June 21st, and that you are on the

440 SCHOOL SCIENCE AND MATHEMATICS

Equator. Where is the sun shining down directly at noonon that date? (We find that it is on the line of latitude231^ degrees North of the Equator.) In what directionthen would you look to see it? (The direction is, of course,North.) How many degrees away from the zenith? (231^degrees.) Locate it with a dot on the semi-circle. Withyour ruler connect up the dot representing the sun and thetop of the line representing the object, and draw theshadow which would be cast by it. (3) Do you see that theshadow for Dec. 22, although of the same length as on June21st, would be cast in the opposite direction? Why?

Going on to parts d and e, the children are referred tothe readings at the beginning of the unit, and write out re-ports under these headings to be handed in later.

In contrast to the sun-shadows at the Equator, we nextchoose a place 70 degrees North of the equator and workout the sun-shadows in a similar way. We find that onMarch 21st, the sun at noon is shining down directly onthe equator, and that we should see the sun as many de-grees away from the zenith as we are degrees away fromthe equator, or 70 degrees to ’the South from directly over-head. The height of the sun then would be 20 degrees abovethe Southern horizon at noon, and the length of the shadowwould be found as before.On June 21st when the sun is shining down directly at

231/2 degrees North of the equator at noon the position ofthe sun for us would be 70 degrees minus 23^ degrees or46^ degrees away from the zenith to the South. Theshadows you see would be considerably shorter than onMarch 21st since the sun would be higher in the sky, andits rays more direct. The position of the sun on September22 at noon would be exactly the same as on March 21. Butlet us see what would happen on December 22. The sun thenat noon would be shining directly above the line of latitude23y^ degrees South of the equator so that in 70 degreesNorth latitude, its position would be 70 degrees plus 23^degrees or 93^ degrees South of the zenith. This is, ofcourse, 3^ degrees below the horizon, so that the sun onthat day would not be visible at any time, and naturallythere would be no shadow. The children are usually muchsurprised to find this so, and it delights them to think that

MOTIVATION IN GEOGRAPHY 441

they have discovered something for themselves. Havingworked out the sun-shadows and having found, from theirtables, the length of the day, they again come back to partsd and e, answering the same questions for this latitude asthey did for latitude 0 degrees at the Equator. That is,they relate these facts back to the types of agriculture,vegetation, types of animals, and the work and civilizationof man, in so far as that is possible, remembering, ofcourse, always that altitude, and winds and ocean currentsplay a part in determining temperature as well as does thedistance from the equator.

Reading for Unit VIII. Temperature as affected by:

A. Distance from Equator1. New Physical Geog. (Tarr and von Engein) pp. 453-

455; 401-404; 405-406; 409-4112. CTmate (Ward) Chap. I3. Climate of the U. S. (Ward) pp. 11-234. H. S. Geog. (Dryer) pp. 172-1815. Intro. to Econ. Geog. (Jones and Whittlesey)

pp. 170-1716. Modern Geog. (Salisbury, Barrows and

Tower) pp. 34-40Unit VII

Probably the one thing or element of our natural environment towhich we must adjust ourselves most often is climate, or the condi-tions of the atmosphere, including temperature, rainfall, pressureand winds, which vary not only from p^ace to place at the same time,but often also at the same place from time to time. We shall studyeach one separately, trying to explain the reason for the distributionand variability so far as that is possible, and then relate theseconditions back to the human activities and adjustments.I. Temperature as affected by:

a. Distance from EquatorTemperature does not vary consistently as does the sun becauseof other factors which enter in to change it. These we shallstudy later. But the position of the sun in the sky does playa very important part in determining the temperature of acertain area, the reason for which you will find in your lesson.We shall, therefore, draw sun shadows which will show youthe position of the sun in the sky at noon. We shall work a

$UA< Z

Ato/y 21

442 SCHOOL SCIENCE AND MATHEMATICS

few of these out together first. Then you will work othersout for yourself later.1. The Equator

Draw a line around your protractor making- a semicircleto represent the heavens. Let the object which is to castthe shadow be ^ inch high, and place it directly belowthe Zenith. Now suppose that you are on the Equator onMarch 21st. Where is the sun shining down directly onthat date? Where then would you look to see the sun?Locate it with a dot on the semicircle. Would there be

. any shadow?b. Now suppose that the date is June 21st, and that you

are on the Equator. Where is the sun shining downdirectly at noon on that date? In what direction thenwould you look to see it? How many degrees away fromthe zenith? Locate it with a dot on the semicircle.With your ruler connect up the dot representing thesun and the top of the line representing the object, anddraw the shadow, which would be cast by it.

JUNE i1

c. Do you see that the shadow for Dec. 22nd, although ofthe same length as on June 21st, would be cast in theopposite direction? Why?

d. Do you believe that so far as the change in position ofthe sun is concerned that the temperature at the equatorwould change much from time to time? How is thisrelated to

(1) Type of agriculture(2) Vegetation(3) Type of animals(4) Man

(a) His work(b) His civilization

e. Make a list of important places where the sun shadowsas approximately as drawn above.

2. At a place 70° North of the Equatora. In the same way we shall work out the sun shadows for

a place 70° North of the Equator for the same threedates at noon. Where is the sun shining down on March21st? You will then see the sun as many degrees awayfrom the Zenith as you are away from this particularpoint. Draw the shadow as you did before.

b. Where is the sun shining down directly at noon on June21st? Do you see that your distance in degrees fromthis point is 70°�23^° or 46 V20?

MOTIVATION IN GEOGRAPHY 443

2

/WCH ^

c. Where is the sun shining down directly at noon on Dec.22? The distance now will be rJOO�221/20. Why? Willthere be any shadow on this day? Note that the sun isbelow the horizon at noon.

Dec zi

d. Answer the same question as in 1 c? above.e. Same as 1 e above.

3. You will now draw shadow pictures for each of the lati-tudes 10° apart, both North and South of the equator forMarch 21st, June 22nd, and Dec. 21st.a. Be able to answer the same questions for each as in

1 d above.b. Make a list of all important places in each latitude

(or approximately so), where these conditions are found.c. Make a special study of wheat farming in Argentina and

the U. S. Note the reverse of conditions and explainthis situation. Study the advantages and disadvantagesof such a situation in:

(1) Exchange of products(2) Migration of man