Joy of Geography

It is quite astonishing that adults know so little of the world around them. They possess a poor subjective understanding of History and little or no understanding of Geography. Science of course is elevated to a religious height with even less understanding. After fourteen years of schooling it is quite interesting to see how little has been learnt of these school subjects by most of us.

There seems to be a divide or disconnect between what is learnt at school and real life. Everyone—well, almost everyone—has a good understanding and feel for at least the front end of the objects and equipment that he/she uses in everyday life. Yet, if one is not in control of something—the natural phenomena around us, for instance—there doesn’t seem to be a need to understand. Therefore, in order to begin understanding these phenomena we need to find a connection between the real world and ourselves. In my opinion, the subject of Geography helps us connect with the world around us very well. When we engage with it seriously, it helps us to demystify the physical world around us and gain a fairly clear understanding of its workings.

I would like to share my experience of teaching Geography to Class 9 students.

Understanding longitudes and latitudes

There is much joy in learning to use the tools which will help us understand even the simple mysteries of the world around us. For instance, take the case of longitudes and latitudes which seems such a ‘text-bookish’ topic at first sight. Yet, an understanding of this simple concept helps us become clear about something that befuddles most adults. It is befuddling and indeed quite magical to realize that when it is summer in one part of the world, it is winter elsewhere, or that the length of the day can vary from twelve hours in some places to a mere three to four hours in other places. But when we find out why it is so, it is exciting for adult and child alike. It is exciting to know that if one flies from India to the United States one gains almost a whole day and that we can lose a day the other way around! It is as exciting to know that if we live in Alaska, close to the International Date Line, we can celebrate two Christmases or two birthdays on consecutive days by just crossing the line! All this and more can be understood and explained by studying the concept of latitudes and longitudes which are just imaginary lines created to help us solve these mysteries.

Isn’t it fascinating that by merely finding out the latitude of a place we can ascertain the approximate climatic conditions there; or by knowing the longitude of a place we can find out the time difference between where we are and that place? Today with sporting events being followed all over the world, sports fans know these time differences by heart. Yet, they may not know the reason behind the difference or only have a vague notion about it.

By understanding the concept of latitudes we will see why the proverbial North Wind is much feared in the northern countries. It helps explain why there are rain forests along the Equator with such a diversity of species. It helps us understand the winds and why it rains and much else. It is indeed a profound tool in the hands of a good teacher.

Once in an atlas study class I realized with shock that Africa straddles all the three major latitude lines: the Equator, the Tropic of Cancer and the Tropic of Capricorn. When most people think of Africa, what comes to their mind is the word, ‘hot’! However, when we look closely we realize that countries like Morocco, Egypt and large parts of Algeria and Libya (which are north of the Tropic of Cancer) and countries like South Africa, parts of Namibia and Botswana (south of the Tropic of Capricorn) actually experience temperate climates and may even have snow-fall!

Another intriguing topic is that of seasons. What causes seasons? Why are there different seasons in different parts of the world at any given time? Why is the experience of seasons so different in different places? For instance, why is summer in Delhi so different from the summer in London or even in Chennai? Most adults seem to think that the earth is closer to the sun in summer than at other times of the year. It would be good practice here to examine the factors that cause the seasons—the rotation of the earth, the revolution of the earth around the sun, and the inclined axis of the earth. What would be the conditions if one of these factors was absent? For instance, if the earth was tilted and rotating but did not revolve around the sun, what would the condition be then? It is an interesting exercise. All permutations and combinations can be imagined, and their consequences worked out. Then one would realize that more than distance from the sun, it is the orientation of the tilted earth in relation to the sun which changes as the earth revolves, and that this is what causes changes of season.

Studying the moon

For many years now I have begun the teaching of Class 9 Geography with observation and study of the moon and its movements with the students. We read the first chapter of the textbook which lists the great discoveries in astronomy made over the centuries. What is astonishing for us is that the discoveries were made with the crudest instruments or no instruments at all—that the mysteries of the heavenly bodies were unravelled through simple observation!

The pioneers were motivated by their curiosity and desire to understand the world around them. When they are really young all children seem to have this quality of curiosity. They often ask questions such as: Why is the night dark? Why do stars twinkle? How far away are the stars? How many stars are there? Some of these questions get answered, often in a pedantic way, at different levels of schooling. Over the years the students begin to take the ‘facts’ for granted and seem to lose their curiosity. I use the study of the moon to rekindle their curiosity and to help the students learn some substantial facts through their own observation.

I start by asking them where the moon rises and when. A number of possible answers are given. Most say that it rises in the night and, as for the direction, many say it rises in the West. ‘The sun sets in the West and the moon rises from there,’ is an oft repeated comment.

I then encourage children to observe the moon over the next few days. They need to look for the moon in the sky whenever they remember and make note of the position. Many come back over the next few days excitedly saying that they had seen the moon in the morning, afternoon or evening—as though for the first time. After a week or so of observation sustained through encouragement, the class arrives at the discovery that the moon rises at a different time every day and that it rises in the East! Some are yet not sure!

Now we try to set about learning why this is so. Several interesting simulations are possible. In one, the whole class stands and moves around in a circle. The students represent the earth moving on its axis. One person, who represents the moon, goes round this rotating circle slowly. When the earth circle has completed one round (representing one day), the moon has moved some distance from its earlier location along its orbit. In this case when student X reaches the point where he was in line with the student moon, the student moon has moved ahead. The time taken for the same point on earth to be in line with the moon again constitutes the delay in the moon rise every day.

One can arrive at this time delay (approximately) by means of some simple mathematics. The moon takes twenty-eight days to complete one revolution. In other words it would have moved one-twenty-eighth of the distance around the earth in one day. The earth completes one rotation in twenty-four hours. The extra time that any point on the earth will take to cover this additional distance to be in line with the moon can be arrived at with some thumb rule calculations. Such exercises are of great value because they help children to rediscover ‘facts’ handed down from the past. While it is no doubt exciting to learn these facts anew, it also demystifies handed down concepts and beliefs.

We next move to eclipses. All we need is a dark room, balls of different sizes and a good torch light and the mystery of the eclipses can be solved by modeling the positions of the sun, earth and moon relative to each other. If one is willing to extend oneself, one can make simple contraptions to hold the light source and the ball and demonstrate different positions. Eclipses occur due to the sun, moon and the earth being in a straight line. Why every full moon and new moon is not an eclipse then needs to be taught with a little more intricacy and attention to detail.

Why are there phases of the moon? One day a few years ago while observing the moon around the time of sunset, it dawned upon me (finally!) that at any point of time half the moon is always illuminated by the sun’s rays. However, we see only a sliver or increasingly larger parts of the moon due to the changing angle at which the moon is with respect to our location on earth. This is the point that needs to be taught. This can be shown both by using the above model and through the circle method used earlier.

Another intriguing fact we learn is that we only see one face of the moon always. This can’t be taught through direct observation but we learn that the time taken for the moon to complete one revolution and one rotation is about the same. With a bit of visualizing we can understand why we see only one face.

If the moon rises at a different time every day does it rise sometimes with the sun and set with the sun too? The answer can be arrived at by direct observation. We find that on new moon days the moon and sun almost coincide in their rising and setting. Strangely, I haven’t seen this point mentioned in any book. I still haven’t been able to discover whether on full moon day the moon rises at six o’clock in the evening at most locations.

Why does the wind blow?

The other fascinating area is that of weather and climate. As much as we have studied it and with the latest technologies, weather prediction remains an elusive science. This is hardly surprising! The number of factors that decide the weather in a given place seems quite beyond human imagination and calculation. Climate on the other hand is more predictable as it follows broad patterns.

Why does the wind blow?  This seems to be a question for poets who have taken the license to wax eloquent about it. But why does the wind blow? When we actually get down to teaching it, the intricacy of it initially baffles students. What we call wind is the movement of air from a region of high pressure to a region of low pressure. The differential heating by the sun causes differences in pressure in different regions. Why there is differential heating and how that leads to difference in pressure are interesting questions to go into.

There is an opportunity here to understand pressure and temperature in a real-life setting as different from studying it in the context of Chemistry. For instance, students learn that, according to the gas laws, pressure and temperature are directly proportional—which means that, when temperature increases, so does pressure. Some sharp students point this out and ask how it is that in the context of studying wind, pressure reduces when there is an increase in temperature. The difference is that when looked at in the context of Chemistry one is looking at fixed volumes or confined spaces, while here it is quite the opposite.

Then we go a little deeper. We have to explain that on heating, particles, or as in this case, molecules of air, gain kinetic energy and tend to move apart. As they move apart there is nothing to restrict them, so they keep moving until they lose their energy and cool down. In geographical terms we describe this as the rising of hot air. When hot air rises it leaves an area of relatively low pressure behind. And when a region is not getting heated or when it is cool the air molecules come closer together and they create higher pressure. Here again is an amazing facet of nature that seems to work in so many contexts—whenever there is a difference in pressure there is a force to equalize it. The same force works in plants to create osmotic pressure so critical in the movement of water and other fluids in plants. In the atmosphere the air moves from a region of higher pressure to a region of lower pressure trying to equalize it.

Here comes the next concept: that of the Coriolis Effect. It is fascinating to note that the air from the region of higher pressure never reaches the region of lower pressure, because it gets diverted. What does this imply? It implies that since the pressure will not get equalized, the air will go on moving in this direction for a very long time or in the case of local regional differences, until the conditions change.

The cause for this diversion is the force created by the high-speed rotation of the earth. It is easy to demonstrate this to students. Students love spinning things on their fingers. One can have one student spin a basketball on his or her finger and ask another student to draw a straight vertical line on it with a sketch pen. This line represents the path taken by the air from a region of high to low pressure. When the ball comes to a stop one notices the line has curved in the opposite direction to which the ball was spinning suggesting that winds blowing in an apparently straight path too will get deflected by the rotation of the earth. This effect is named after the man who discovered it, Gaspard de Coriolis. The demonstration can be done with a flat disc or even a note book.

Thus we have regions of permanent high pressure and regions of permanent low pressure. These are called pressure belts and winds move between them all through the year. These are called permanent winds, and sailors and others have known and used these winds since time immemorial.

Making a connection with the earlier understanding of temperature and pressure, it is easy to explain that there will be a low pressure belt around the equator as it is the region which experiences the highest temperature due to the direct rays of the sun. By the same logic the poles will be the regions with the highest pressure. And yet, further complexity is introduced into this system of pressure belts by the fact that the tilted axis of the earth causes the direct rays of the sun to shift somewhat south and north of the Equator (up to the limits of the tropics of Capricorn and Cancer) as the seasons change. Hence one must visualize even the permanent winds shifting northward or southward with seasonal changes.

There are many more interesting phenomena like ocean currents and the course of rivers which one can go into in detail. My purpose in this article has been to show how joyous and enriching an experience the study of Geography can be; hence these examples should suffice.

Comments

Jyothsna's picture

Excellent  Arun! Very interesting. I enjoyed reading it and am going to share in my class too! Thank you 

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