Class 6 Social Science Chapter 3: Landforms and Life

Land has a shape

Human beings, like most mammals, live on land, and land is not the same everywhere, and anyone who has travelled will have noticed it. Imagine a road journey from Chhota Nagpur in Jharkhand to Prayagraj in Uttar Pradesh, and on to Almora in Uttarakhand. The view from the window would change completely along the way. You would pass through three quite different kinds of country, and those three are what this chapter is about.

What a landform is

A landform is one of the shapes the Earth's surface takes. It is not made in a season or a lifetime. A landform is made over millions of years, and each one is tied closely to the environment around it and the life it supports. They are usually sorted into three main kinds: mountains, plateaus and plains. Each has its own climate, its own plants and animals, and its own way of life.

Recognising a mountain

A mountain is a landform standing much higher than the land around it. Three features together give it away. It is wide where it meets the plain, steep along its sides, and it tapers as it rises. Notice that all three are needed. Height alone is not enough, because a plateau can be high too, and we shall see why it is a different thing altogether.

Mountain, or hill?

Not every raised piece of land is a mountain. Some highlands are lower, with slopes that are far less steep and tops that are rounded rather than pointed. These are hills. The difference is not only size. A hill's gentler shape usually means it is older, worn down over a long time, and easier to live on and to farm.

Snow and where it stays

Many mountains carry snow, and how long it stays depends on altitude. Lower down it falls in winter and melts away each summer, and that meltwater runs off to feed the rivers below. Higher up the air is cold enough that the snow never melts at all. Such a peak stays white all year, and we call it permanently snow-capped.

What snow actually is

Unless you live in a Himalayan region, you may never have seen snow. In most of India, water arrives from the sky as rain or hail instead. All three count as precipitation, a word covering every way water leaves the sky and reaches the land. Snow and hailstones are that water in a solid state. It needs to be both high enough and cold enough for snow to fall.

Mountains come in ranges

Most of the world's mountains do not stand alone. They are grouped into mountain ranges, and some of these stretch for thousands of kilometres. The Himalayas run across Asia. The Alps rise in Europe. The Andes run down South America. Learning the range along with the continent saves learning each peak separately.

Six mountains worth knowing

Mount Everest, between Tibet in China and Nepal, is the highest peak of the Himalayas and of the world. Kanchenjunga, between Nepal and Sikkim, is the second of the Himalayan giants. Aconcagua tops the Andes, in South America. Mont Blanc is the highest of the Alps. Anamudi, in Kerala, is the highest mountain in south India. Kilimanjaro, in eastern Africa, belongs to no range at all.

Young mountains, old mountains

Sharp, tall peaks like those of the Himalayas are called young. That word means recent in the Earth's history, which is still millions of years ago. Short, rounded ranges like the Aravalli are far older, and time has worn their edges away by erosion. The Himalayas are unusual in that they are still being pushed upward while erosion works on them, so they are growing even now.

The forest on the slope

Mountain slopes are often covered by montane forest. The trees that do best there are conifers: pine, fir, spruce and deodar. A conifer rises in a tall cone, and carries needles rather than broad flat leaves. That shape suits a cold, snowy place, because snow slides off a narrow tree instead of piling up and breaking its branches.

Where the trees stop

Keep climbing and the forest thins and then ends. Above that point the cold and the wind are too much for trees. What survives instead is low and tough: grasses, mosses and lichen. A moss grows in low, soft, spreading patches, with no flowers and no proper roots. A lichen is not quite a plant. It grips bare rock, walls or bark, and survives where nothing else will.

The animals of the high country

Deep forest, rivers, lakes, grassland and caves between them give mountains a remarkable range of animals. Among them are the golden eagle and the peregrine falcon in the air. On the slopes there are the ibex, the Himalayan tahr, the yak and the mountain hare. Hunting them are the snow leopard, the Canadian lynx, the grey fox and the black bear.

Water off the mountain

What falls as snow up high ends as river water below. The Ganga is the largest river rising in the Himalayas, running nearly 2,500 kilometres, and many smaller rivers join it on the way. A river that joins a larger one is called its tributary. The Yamuna and the Ghagara are Himalayan tributaries of the Ganga. The Son, by contrast, comes from the Vindhya Range to the south.

Scenario:

Two pupils argue about mountain weather. Arjun says a mountain is cold because it is far north. Nita points out that there are cold mountains near the equator. Their teacher asks the class what changes as you climb. The children list it: the air thins, and it holds heat less well. The class then compares two places at the same latitude, one on a plain and one high on a slope, and finds the higher one colder. Arjun's rule fails and height explains both cases. The class writes it down. Latitude matters, and so does elevation, and a mountain is cold chiefly because of the second.

Analysis:

Arjun's explanation worked for mountains in the north and failed at the equator. Height accounts for both, which is why it is the better rule.

Activity:

Find two places in India at a similar latitude but very different heights. Compare their January temperatures and explain the gap.

Title:

Build the three landforms in sand or dough

What You Notice:

The plateau and the mountain can be built to the same height and still look nothing alike, which is the whole point about shape. You will also see that water always finds the low ground, which is why rivers rise in the mountains and cross the plains.

Safety:

Keep the water to a trickle so the tray does not overflow, and wash your hands after handling damp sand.

Mount Everest stands 8,848 metres high and is the tallest mountain in the world. It lies between Tibet, in China, and Nepal.

Mount Kilimanjaro in eastern Africa belongs to no range at all. It rises on its own, which is unusual for a mountain of that size.

Some mountains are still growing. The Himalayas are being pushed up even now, while erosion wears them down at the same time.

The shape of a mountain — Wide foot, steep sides, small top — All three at once. A hill may be wide at the foot too, but its sides are gentle and its top is rounded.

Which range is where — Him-Asia, Alps-Europe, Andes-America — The Himalayas in Asia, the Alps in Europe, the Andes in South America. Each name sits beside its continent.

Ground that fights back

Terrain means land described by what it is physically like, and mountain terrain is a hard master. It is usually rugged or rough, and its slopes are steep. That single fact decides much of mountain life. You cannot plough a steep slope, because the plough will not stay level and the soil will slide away. So ordinary farming is possible only where the ground flattens out, which mostly means in the valleys.

Cutting steps into a hillside

Mountain farmers found an answer long ago. Instead of fighting the slope, they cut it into steps. Each step is a narrow strip of level ground, and behind each one the soil is held in place. This is called terrace farming, and from a distance a terraced hillside looks like a giant staircase. It is slow, heavy work to build, and every wall has to be kept in repair.

Why terraces do more than flatten

A terrace does two jobs at once. The obvious one is giving a level surface to plant on. The quieter one matters just as much. On a bare slope, rainwater runs straight down and takes the topsoil with it. A terrace catches that water and holds the soil in place behind its wall, so the field is still there next season.

Herding instead of farming

Across much of the world's mountain country, people herd rather than plough. The reason follows from the terrain. Animals can graze ground that no plough could ever work. Goats, sheep, yaks and cattle will walk up a slope, feed on the grass above the tree line in summer, and come back down as the cold arrives. A herd turns useless ground into food, wool and milk.

Visitors as a living

Visitors bring in a good part of the money earned in the mountains. The crisp air and the scenery draw people up from the plains. Some come for the sport, whether skiing, hiking, mountaineering or paragliding. Others come for the quiet. For a mountain family, a season of visitors may bring in more than a season of crops ever could.

Travelling to sacred places

People have been walking into the uplands for a great deal longer than tourism has existed. For many centuries they have gone on pilgrimage to holy sites in the mountains. The routes are old, the halting places are old, and whole local economies grew up along them. That long habit is part of why some mountain towns are busy places rather than remote ones.

When there are too many

Visitors bring money and they also bring pressure. A mountain environment is fragile, and an excessive inflow of people can damage it faster than it can recover. Rubbish piles up where nobody can easily carry it away. Water and fuel run short. Building spreads onto slopes that should have been left alone. Finding the right balance between welcome and protection is genuinely difficult, and there is no simple rule for it.

Earth that gives way

Steep ground and heavy rain together make landslides. A landslide is earth or rock breaking loose from a mountainside and coming down all at once. It can bury a field, block a road for days, or cut a village off from help altogether. Because the road is often the only way in, a landslide far from a village can still leave it stranded.

Water arriving all at once

A cloudburst is a short, furious burst of rain, and in the mountains its water has nowhere gentle to go. It runs off the slopes and gathers in the valleys. The result may be a flash flood, which rises in one place with almost no warning. A cloudburst is its usual trigger. What makes a flash flood dangerous is the speed. There may be very little warning between the rain and the water.

Snow that lets go

An avalanche is the sudden fall of snow, ice or rock down a mountainside. It often happens when the snow begins to melt, because melting loosens the grip that held the mass in place. A great weight of snow that has sat still all winter can move in seconds. Anyone or anything on the slope below has almost no time.

The slow dangers too

Not every mountain difficulty is sudden. Heavy snowfall can close a pass for weeks and keep supplies from reaching a village. Cold weather lasts for months and makes fuel, shelter and warm clothing matters of survival rather than comfort. And uncontrolled tourism belongs on this list as well, because it is a danger people have made rather than one the mountain has.

Two Indian climbers

Mountains have also drawn people determined to reach the top. Bachendri Pal began climbing young and led many women's expeditions. In 1984 she reached the summit of Everest, the first Indian woman to do so. The Padma Shri came that year and the Padma Bhushan in 2019. Arunima Sinha had lost a leg in an accident at twenty-two. With Bachendri Pal's encouragement and training she climbed Everest in 2013, then reached the highest point of every continent, and received the Padma Shri in 2015.

Mountains held sacred

Many traditional communities around the world regard mountains as sacred and worship them. Everest itself carries several names. Tibetans call it Chomolungma, meaning Mother Goddess of the World, and honour the mountain as such. Nepalis call it Sagarmatha, Goddess of the Sky. In Tibet, Mount Kailash draws reverence from four traditions at once: Hinduism, Buddhism, Jainism, and the old Tibetan religion called Bon. Such reverence for summits is found across India and in many other parts of the world.

Scenario:

A village sits on a steep slope in Uttarakhand. Its families farm narrow terraces and keep goats on the grass above the forest. Ten years ago a road reached the village, and visitors began arriving in summer. Two guest houses were built and the income was welcome. This year the numbers trebled. The spring that supplies the village ran low in May. Rubbish collected on the path to the viewpoint, and nobody could carry it down. In July a cloudburst sent a flash flood through the lower terraces, and a landslide closed the road for nine days. The panchayat must now decide what to do about next summer.

Analysis:

Two different things happened here and it would be easy to muddle them. The cloudburst, the flash flood and the landslide are natural mountain dangers. Steep ground and sudden heavy rain produce them, and they would have come whether or not the road existed. What the road changed is how quickly help arrives and how long the village is cut off, because that road is the only way in. The water shortage and the rubbish are different. They are human-made, caused by more visitors than the place can carry. A mountain environment is fragile, and an excessive inflow damages it faster than it recovers. So the panchayat is really facing two questions, not one. For the natural dangers it can prepare: keep terrace walls in repair, avoid building on the most unstable slopes, and plan for the road being shut. For the visitor pressure it must choose a number it can live with. Tourism is a genuine opportunity, and the difficulty lies in the balance rather than in the visitors themselves.

Activity:

Draw a table with two columns, headed Natural and Human-made. Place every event from the passage in one column. Then add a third column headed What would help, and write one practical step beside each event.

In 1984 Bachendri Pal reached the summit of Everest, the first Indian woman to do so. She was awarded the Padma Shri that same year and the Padma Bhushan in 2019.

An accident cost Arunima Sinha a leg when she was twenty-two. Bachendri Pal trained and encouraged her. She reached the summit of Everest in 2013, then the highest point of every continent.

In Tibet, Mount Kailash draws reverence from four traditions at once: Hinduism, Buddhism, Jainism, and the old Tibetan religion called Bon.

Why terraces work — Turn a slope into stairs — A staircase is made of flat steps, and so is a terraced hillside. Each step is level enough to hold soil, water and a crop.

The sudden dangers of a mountain — Earth, water, snow — Earth slides in a landslide. Water arrives all at once in a flash flood or cloudburst. Snow comes down as an avalanche.

High, and flat on top

A plateau rises up from the land around it, but there the resemblance to a mountain ends. Its surface on top is more or less flat, and some of its sides drop away in steep slopes. Height is not the difference between the two, because plateaus can be very high indeed. They stand anywhere between a couple of hundred metres and a few thousand. Like mountains, they may be young or old in the Earth's history.

Two plateaus worth knowing

The Tibetan Plateau is the largest and the highest in the world, and its average height is 4,500 metres. That has earned it a nickname: the Roof of the World. From east to west it runs nearly 2,500 kilometres, roughly as far as Chandigarh is from Kanyakumari. The Deccan Plateau, across central and south India, is quite different. It is among the world's oldest plateaus, thrown up by volcanic activity millions of years back.

Storehouses of minerals

Plateaus, like mountains, are rich in mineral deposits, and they have been called storehouses of minerals for that reason. So mining is a major activity on them, and many of the world's largest mines sit on plateaus. The East African Plateau is famous for gold and for diamonds. In India, the Chhota Nagpur Plateau holds huge reserves of iron, coal and manganese.

Soil, and one exception

The plateau environment differs greatly from one part of the world to another. The soil on many plateaus is rocky, so it grows less than a plain would, and suits farming less well. There is one notable exception. Lava plateaus, formed by volcanic activity, often carry a rich black soil instead. That is why a plateau built by volcanoes can be good farmland while its neighbour is not.

Water off the edge

A plateau has a flat top and steep sides, and a river running across it must eventually reach that edge. The result is a waterfall, and plateaus are home to many spectacular ones. The Victoria Falls plunge off the Zambezi in southern Africa. The Hundru Falls belong to the Subarnarekha, on the Chhota Nagpur Plateau. The Jog Falls belong to the Sharavati River in the Western Ghats. In Meghalaya the Nohkalikai Falls drop 340 metres off the Cherrapunji Plateau.

What makes a plain

Plains are the third of the main landforms, and the easiest to describe. A plain has an extensive surface that is flat, or gently undulating rather than sharply up and down. It holds no large hills and no deep valleys. A plain rarely rises above 300 metres from the ocean's average level, which means above the ocean's surface taken at its average height.

How a river builds a plain

One important kind of plain is made by rivers themselves. A river rising in a mountain range picks up particles of rock, sand and silt as it goes. Those particles are called sediments. The river carries them all the way down, and where it slows on flat ground it drops them. Layer upon layer of dropped sediment makes the soil extraordinarily fertile. A plain built this way is called a floodplain.

Why plains feed people

That fertility explains a great deal. Floodplain soil is ideal for growing crops of every kind, so agriculture is the major economic occupation on this landform. Plains also support a wide variety of plants and animals. It is no accident that the first civilisations grew up around rivers in fertile plains. Even now, a large share of humanity lives on plains.

The Ganga plain

India's Ganga plain, often called the Gangetic plain, carries about 40 crore people. That is more than one-fourth of the entire Indian population living in one stretch of flat country. As in many plains elsewhere, the main occupations are agriculture and river fishing. Food crops include rice, wheat, maize, barley and millets. Cotton, jute and hemp grow there too, for their fibre.

Water for the fields, and a cost

Traditionally, farming in the Ganga plain was rainfed, meaning the crops were watered by rainfall alone. In recent decades it has turned to irrigation instead, with water brought through canals or pumped up from underground. Production has risen as a result. But the pumping has also drawn down the groundwater, and that depletion is a serious problem for the future of farming there. High population and pollution add to the region's difficulties.

Rivers, culture and travel

Rivers matter to people for more than their water. Across the world they carry immense cultural value, and many communities treat a river's source as sacred. So is its confluence, where two rivers or more run together into one. In India, festivals, ceremonies and rituals are held at such places. A plain's slope is gentle, so boats move along its rivers without difficulty, and along stretches of the Ganga people still prefer a boat to a road.

A fourth kind of country

The Earth's surface is complex, and experts often name more than three landforms. The desert is one such addition. Deserts are large, dry expanses receiving very little precipitation, and their plants and animals are unlike those found anywhere else. Some are hot, such as the Sahara in Africa and the Thar in the north-west of the Indian subcontinent. Others are cold, such as the Gobi in Asia. Some experts even describe Antarctica as a desert.

Making a home anywhere

Despite harsh conditions, people have settled in most of the deserts of the world. A rich culture of folk song and legend, much of it about the desert, is kept in India. Those who live in the Thar Desert keep it, and so do those whose route crosses it. Ancient Tamil Sangam poetry took a different approach to landforms altogether, sorting the country into five landscapes each with its own way of life. That the same land can be classified in more than one way is worth noticing. So is the deeper point: the many ways people have made every landform their home say a great deal about human adaptability and resilience.

Scenario:

A class is given four photographs and asked to name the landform in each. Three are agreed quickly. The fourth, a flat dry expanse, splits the class between plain and desert. Their teacher asks what each word is answering. Plain describes the shape of the land, and desert describes how much rain it gets. Both labels can be true of one place at once, because they are answers to different questions. The class rewrites its labels to carry both where needed. Rohit notes that the Tibetan Plateau is high, flat and dry, so shape, height and rainfall each need their own word.

Analysis:

The argument was not about the photograph but about which question the label answers. Shape and rainfall are independent, so one place can need both words.

Activity:

Describe a landform near you using three separate words for shape, height and rainfall. Say which one a photograph cannot tell you.

Title:

Make a river build a plain

What You Notice:

The water always carries the fine material downhill and leaves it on the flat, which is exactly how a floodplain is built. Flattening the top turns your mountain into a plateau, and the water then drops over the edge in a small waterfall — the same reason real plateaus have so many.

Safety:

Pour slowly so the tray does not overflow, and work over a sink or outdoors.

The Tibetan Plateau averages 4,500 metres in height, which is why it is nicknamed the Roof of the World. From east to west it runs nearly 2,500 kilometres.

The Nohkalikai Falls in Meghalaya drop 340 metres off the Cherrapunji Plateau, one of many spectacular waterfalls that plateaus produce.

About 40 crore people live in the Ganga plain. That is more than one-fourth of everybody in India, in a single stretch of flat country.

Telling a plateau from a mountain — High, but flat on top — Both rise above the land around them. Only the mountain narrows to a summit; the plateau keeps a broad, level top.

Why a plain is fertile — The mountain sends its soil downstream — Rivers pick up sediments high up, carry them down, and drop them on the plains. The plain's richness is borrowed from the hills.