English:Mountains, Valleys, and Plains
Mountains, Valleys, and Plains
Introduction
Look around any landscape and you will see shapes in the land. Some places rise high into the sky, some dip between higher areas, and some stretch out almost flat. These natural shapes are called landforms. In this aiMOOC, you will explore three important landforms: mountains, valleys, and plains.
Mountains, valleys, and plains are connected. Water can fall as rain or snow on mountains, flow downhill through valleys, and carry small pieces of rock and soil toward lower, flatter land. Over very long periods of time, forces inside Earth and processes at the surface build, wear down, and reshape the land.
The image above shows high mountains beside much flatter land. Compare the height, steepness, and shape of the two areas. What clues help you decide where the mountains end and the flatter land begins?
Watch with a purpose: As you watch, listen for the names of different landforms. Pause when you see a mountain, valley, or plain and describe its shape in your own words.
Learning Goals
By the end of this course, you should be able to explain what mountains, valleys, and plains are; compare their shapes and elevations; describe simple ways they form; explain how water, ice, weathering, erosion, and deposition change landscapes; identify these landforms in photographs and maps; and connect landforms with plants, animals, farming, transport, settlement, and natural hazards.
What Is a Landform?
A landform is a natural feature of Earth's surface. Landforms differ in elevation, which means height above a reference level, and in slope, which describes how steep or gentle the land is.
A landscape may contain several landforms at once. A mountain range can include peaks, ridges, passes, and valleys. A river can leave a mountain valley and then cross a broad plain. This is why geographers study both individual landforms and the ways they connect.
Two groups of processes help shape landforms. Building processes include movements of Earth's crust and volcanic activity. Reshaping processes include weathering, erosion, and deposition. Weathering breaks rock into smaller pieces. Erosion moves rock and soil. Deposition happens when moving water, wind, or ice drops the material it was carrying.
Mountains
What Makes a Mountain?
A mountain is a landform that rises prominently above the surrounding area. Mountains often have steep slopes, high ridges, and one or more peaks. A connected group of mountains is called a mountain range.
Mount Everest is part of the Himalayas in Asia. It rises more than 8,800 meters above sea level. You do not need to memorize that number. Instead, notice the sharp ridges and the large difference in elevation between high peaks and lower land.
Mountains affect more than scenery. Their height can influence temperature and precipitation. They can provide habitats for plants and animals adapted to steep, cold, windy, or rocky conditions. Mountains can also make roads and travel more difficult, so people often use passes and valleys as routes through high land.
How Mountains Form
Many mountain ranges form because large pieces of Earth's outer shell, called tectonic plates, move. Where plates push together, rock can be folded, faulted, and lifted upward. Some mountains form around volcanoes when lava and other volcanic materials build up over time.
Mountain building is slow on a human timescale. At the same time, weathering and erosion wear mountains down. Water can enter cracks, rivers can cut into rock, ice can scrape surfaces, and gravity can move loose material downhill. A mountain landscape is therefore always changing, even if the changes are too slow to notice from day to day.
Mountain Clues
When you identify mountains in a photograph or on a map, look for strong changes in elevation, steep slopes, peaks, ridges, and narrow passes. On a topographic map, contour lines that are very close together usually show steep slopes.
Valleys
What Is a Valley?
A valley is a low area of land between higher areas. Many valleys are long and contain a stream or river because water naturally flows downhill. Valleys can be narrow or broad, shallow or deep.
Yosemite Valley in California is a famous example of a valley shaped strongly by past glaciers. Look at the wide floor and steep sides. The shape gives clues about the forces that changed the landscape.
River Valleys and Glacial Valleys
Running water can cut into the land. Over time, a river often erodes a valley with a V-shaped cross-section, especially in high or steep terrain. The river usually occupies the lowest part of the V.
Glaciers are huge masses of ice that move slowly over land. A glacier can erode the floor and sides of a mountain valley. Glacial valleys are often broader and have a U-shaped cross-section.
The animation shows how moving ice can widen and deepen a valley. Focus on the change from a narrower valley shape to a broader U-shaped form.
This cross-section of Yosemite Valley helps you see the valley from the side rather than from above. A cross-section is useful because it shows the shape of the land as if Earth had been sliced through vertically.
Watch with a purpose: Notice that a glacier is not just a block of still ice. It moves slowly and can erode rock, transport material, and reshape valleys.
Why Valleys Matter
Valleys often collect water, soil, and sediment. Some have fertile land that supports farming. Valleys can also provide easier travel routes through mountains. However, low valley floors near rivers may flood, and steep valley sides can be affected by rockfalls or landslides. Understanding the shape of a valley helps people plan where to build roads, farms, and homes.
Plains
What Is a Plain?
A plain is a broad area of land that is mostly flat or gently rolling. A plain does not have to be perfectly flat. The key idea is that changes in elevation are usually much smaller and more gradual than in mountainous terrain.
This grassland in Nebraska shows the wide view and gentle relief common in many plains. Plains can support grasslands, forests, farms, towns, or other ecosystems and land uses depending on climate, soil, water, and human activity.
How Plains Form
Plains can form in several ways. Rivers can carry sediment from higher land and deposit it in lower areas. Repeated flooding can build a floodplain beside a river. Wind can also move and deposit fine material. Some plains form where lava spreads across a wide area, and others develop as erosion slowly lowers and smooths older landscapes.
Because some river and floodplain sediments contain useful nutrients and hold water well, many plains have productive farmland. However, not every plain has fertile soil, and farming success also depends on climate, water supply, soil care, and other factors.
This map highlights the Great Plains within the United States. Use it as a location map, not as a picture of the land's surface. A map and a photograph give different kinds of geographic evidence.
Plains Are Not Empty
A plain can contain rivers, wetlands, low hills, farms, grasslands, forests, cities, and roads. The word plain describes the general shape of the land, not whether the place is wild, farmed, crowded, or empty.
Wide, gently sloping land can make it easier to build roads, railways, and large fields than in steep mountains. At the same time, plains may face hazards such as floods, droughts, wind erosion, and severe storms. People need to understand both the opportunities and risks of the landscape.
How the Three Landforms Connect
Imagine a drop of rain falling high in a mountain range. Gravity pulls it downhill. It may join a small stream in a valley. The stream may grow into a river, carrying pieces of weathered rock with it. When the river reaches flatter land, it may slow down and deposit some of its sediment on a plain.
This simple journey shows a chain of connected processes:
Mountains can be source areas for water and sediment.
Valleys often guide streams and rivers through lower pathways.
Plains can receive sediment and water from rivers that have left higher ground.
These connections form part of a drainage basin or watershed. A watershed is the area of land where water drains toward the same river, lake, or other outlet.
Watch with a purpose: Look for examples of weathering and erosion. Ask yourself: Is material being broken apart, moved, or dropped?
Reading Landforms on Maps
Geographers use different maps for different questions. A physical map may use colors and shading to show high and low land. A topographic map uses contour lines. Each contour line connects places that have the same elevation.
If contour lines are close together, elevation changes quickly over a short distance, so the slope is steep. If they are far apart, the slope is gentler. Closed contour lines may show a hill or mountain. Valleys often make contour lines bend into V-like shapes where they cross streams.
When studying a map, do not use one clue alone. Check the legend, scale, contour pattern, rivers, and surrounding landforms. Good geographic reasoning combines several pieces of evidence.
People, Plants, and Animals
Landforms influence how living things use a place. On mountains, temperature often becomes cooler with increasing elevation, and steep slopes can limit deep soil. Valley floors may have water and deeper sediments. Plains can support extensive grasslands or large farming areas where climate and soil are suitable.
People adapt to landforms too. Mountain communities may use tunnels, switchback roads, or passes. Valley settlements may develop along rivers but must plan for flooding. Plains can support long roads, railways, farms, and cities, yet communities still need to prepare for drought, floods, storms, and soil erosion.
No landform automatically determines how people live. Culture, technology, climate, natural resources, history, and decisions all matter. Landforms are one important part of the system.
Caring for Landscapes
You can help protect landforms and the ecosystems connected with them. Staying on marked trails can reduce erosion on steep slopes. Keeping litter out of streams helps protect valleys and downstream plains. Plant roots can help hold soil in place. Farmers can use soil-conservation methods to reduce erosion, and communities can avoid unsafe building in places with high flood or landslide risk.
When you visit a mountain, valley, or plain, observe carefully and leave the place as you found it. Learning geography is not only about naming features. It is also about understanding relationships and making responsible choices.
Reliable Sources for Further Reading
- National Geographic Education - Landform: An overview of landforms and the processes that shape them.
- National Geographic Education - Plain: An explanation of different ways plains can form.
- U.S. Geological Survey - Rivers and the Landscape: Information about rivers, floodplains, erosion, deposition, and human uses of rivers.
- U.S. Geological Survey - Geology of Glacier National Park: Examples of glacial erosion and U-shaped valleys.
Interactive Tasks
Quiz: Test Your Knowledge
Which description best fits a mountain? (A landform that rises prominently above nearby land) (!A flat area covered only by grass) (!A low area that always contains a lake) (!A human-made wall beside a road)
Which description best fits a valley? (A low area between higher areas) (!The highest point of a mountain) (!A completely flat ocean floor) (!A pile of loose rocks made by people)
Which description best fits a plain? (A broad area of mostly flat or gently rolling land) (!A narrow crack inside a rock) (!A steep peak covered by snow) (!A deep hole made only by animals)
What does weathering do? (It breaks rock into smaller pieces) (!It moves tectonic plates across Earth) (!It turns every valley into a mountain) (!It makes all plains perfectly flat)
What is erosion? (The movement of weathered rock or soil) (!The measurement of air temperature) (!The naming of a mountain range) (!The building of a road tunnel)
What often happens when a river slows down? (It deposits some of the sediment it carries) (!It always begins to flow uphill) (!It turns into solid rock) (!It removes every plant nearby)
Which valley shape is commonly linked with river erosion in steep land? (A V shaped valley) (!A perfect circular valley) (!A square valley) (!A flat roofed valley)
Which valley shape is commonly linked with glacial erosion? (A U shaped valley) (!A star shaped valley) (!A triangle shaped valley) (!A spiral shaped valley)
What do closely spaced contour lines usually show? (A steep slope) (!A flat ocean) (!A city boundary) (!A road speed limit)
Which statement shows how mountains valleys and plains can be connected? (Water can flow from mountains through valleys and carry sediment toward plains) (!Plains always form above mountain peaks) (!Valleys stop all water from moving) (!Mountains and plains can never occur near each other)
Memory Game
| Mountain | High landform with steep slopes and a peak or ridge |
| Valley | Low area between higher ground |
| Plain | Broad area with mostly gentle changes in elevation |
| Erosion | Movement of weathered rock or soil |
| Deposition | Dropping of material that was being carried |
| Watershed | Land area that drains toward the same outlet |
| Contour | Map line connecting places of equal elevation |
| Sediment | Small pieces of rock or soil moved by water wind or ice |
Drag and Drop
| Match the correct terms. | Topic |
|---|---|
| High landform with steep slopes | Mountain |
| Low area between higher land | Valley |
| Broad gently changing surface | Plain |
| Material is moved to a new place | Erosion |
| Carried material is dropped | Deposition |
...
Crossword Puzzle
| Mountain | What landform rises prominently above the surrounding land? |
| Valley | What low landform lies between higher areas? |
| Plain | What broad landform is mostly flat or gently rolling? |
| Erosion | What process moves weathered rock and soil? |
| Sediment | What word means small pieces of rock or soil that can be transported? |
| Glacier | What moving mass of ice can carve a U shaped valley? |
LearningApps
Cloze Text
Open-Ended Tasks
Easy
- Landform Hunt: Find three photographs in books, magazines, or safe online sources that show a mountain, a valley, and a plain. Label each picture and write two clues that helped you identify the landform.
- Landscape Sketch: Draw one landscape that includes a mountain, a valley, and a plain. Add arrows to show how water might travel downhill after rain.
- Landform Vocabulary: Create six illustrated vocabulary cards for mountain, valley, plain, weathering, erosion, and deposition. Write each definition in your own words.
- Photo Detective: Choose one landscape photograph and record everything you can observe before naming the landform. Separate observations from guesses.
Standard
- Model Watershed: Build a simple landscape model from clay or crumpled paper covered with foil. Spray a small amount of water on the high area and record the path the water takes.
- Valley Comparison: Make a poster that compares a river-cut V-shaped valley with a glacier-cut U-shaped valley. Include one labeled drawing of each and explain the main difference.
- Map Reader: Use a physical or topographic map of a local or familiar region. Identify one high area, one low route, and one relatively flat area, then explain the map evidence for each choice.
- Landform Interview: Interview a family member, teacher, farmer, hiker, driver, or local worker about how mountains, valleys, or plains affect travel, work, weather, farming, or recreation.
Advanced
- Erosion Experiment: Design a fair test comparing how water moves soil on a steep slope and on a gentle slope. Change only the slope, measure or describe the soil movement, and explain your result.
- Settlement Planner: Imagine you must choose a safe place for a small town in a landscape with a mountain, river valley, and plain. Create a map and defend your choice using water access, transport, flood risk, slope, and farming.
- Landform Documentary: Produce a two to four minute video that teaches younger students how mountains, valleys, and plains connect through water, erosion, transport, and deposition. Use your own diagrams or openly licensed media.
- Local Landscape Study: Visit a safe viewpoint, park, river path, museum, or geographic site with an adult or class. Record observations, make a field sketch, identify landform evidence, and compare what you see with a map.
Learning Assessment
- Compare Landforms: Explain two differences and one connection among mountains, valleys, and plains using elevation, slope, water, or sediment as evidence.
- Explain a River Journey: Trace a drop of water from a mountain to a plain and explain where erosion and deposition could happen along the way.
- Interpret a Map: Given a simple topographic map, identify the steepest slope, a likely valley, and a gentler area, then justify each choice using contour patterns.
- Evaluate a Building Site: Compare two possible places for a school or community center and decide which is safer, using evidence about slope, flooding, access, and nearby landforms.
- Analyze a Valley Photo: Decide whether a photographed valley was more likely shaped mainly by a river or a glacier and explain which visible clues support your claim.
- Transfer to a New Place: Choose a landscape you have not studied in this course and predict how its landforms might influence transport, farming, habitats, or settlement. Explain your reasoning.
Evidence of Learning
Knowledge: You can accurately define mountains, valleys, plains, weathering, erosion, deposition, sediment, glaciers, contours, and watersheds, and you can explain basic relationships among them.
Skills: You can observe landscapes carefully, compare landforms, interpret photographs and simple maps, use geographic vocabulary, follow water through a landscape, and support a claim with evidence.
Products: Strong evidence may include labeled diagrams, maps, models, experiment records, field sketches, posters, interviews, presentations, or short educational videos.
Reasoning: You can explain why a landscape has certain features instead of only naming them. You can connect processes such as erosion and deposition to visible landforms.
Transfer: You can apply what you learned to an unfamiliar landscape, make a sensible prediction about water or human land use, and revise your idea when new evidence appears.
OERs on the Topic
For a broad open reference, explore the English Wikipedia article on landforms. You can also follow the internal links in this aiMOOC to read more about individual features.
Linked Learning Areas
Mountains, valleys, and plains connect geography, Earth science, geology, hydrology, ecology, cartography, and environmental planning. Understanding these landforms helps you study how Earth's surface changes and how people and ecosystems respond to those changes.