Mountains, Rivers and a Changing Earth

Look out of the window: do you see hills, a river, maybe mountains far away? The land has many shapes, and it changes. Some changes are fast, some are very slow. Let’s name the shapes of land and water, find them on a map, and see how people protect the land.

This lesson takes about 12 minutes. You can take a break after each part.

Before you start

Mountains, Rivers and a Changing Earth

Learning objectives

  • I can name shapes of land and water: mountain, hill, valley, plain, river, lake, ocean.
  • I can tell fast changes of the land (earthquake, eruption, landslide) from slow ones (erosion).
  • I can compare solutions that slow down erosion by water or wind.

Shapes of land and water

Shapes of the land

The land has different shapes called landforms. A mountain is very high land. A hill is lower and rounder. A valley is low land between hills or mountains. A plain is wide, flat land.

A wide landscape with eight numbered places: 1, a tall snowy mountain; 2, a round green hill; 3, a valley between mountains, with a river; 4, high flat land with steep rock sides; 5, a flat plain with fields and a few houses; 6, a river that winds across the land; 7, a big blue lake with a small island; 8, a deep canyon with a river at the bottom.
1 mountain, 2 hill, 3 valley, 4 plateau (high flat land), 5 plain, 6 river, 7 lake, 8 canyon: find each shape of land and water.

Water on Earth

A river is water that flows across the land. A lake is water with land all around it. The ocean is a huge body of salty water. A map shows a place seen from above: water is often blue.

A small model of a landscape, seen from above: a snowy mountain, a river that comes down in waterfalls, passes under a bridge and flows into a lake, a dam with another lake behind it, and a village with roads and colorful fields.
Seen from above, like on a map: the river is a blue line, the lakes are blue shapes, and the mountain is high land.

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Fast changes and slow changes

Fast changes

Some changes happen fast, in minutes or hours. In an earthquake, the ground shakes. A volcano can erupt: hot lava flows out, then cools and becomes new rock. In a landslide, rocks and soil slide down a hill.

Slow changes

Other changes are slow: they take many, many years. Water and wind carry away tiny bits of rock and soil, little by little. This is erosion. A river can dig a deep canyon this way.

Two pictures. On the left, a volcano on an island throws out smoke and red lava that flows down its sides. On the right, near a village, children and adults with backpacks walk quickly to a bus while the volcano erupts behind them.
An eruption changes the land in a few hours. The people leave the village quickly, with the adults.

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Slowing down erosion

Holding the soil

People can slow down erosion. The roots of grass and trees hold the soil, so the rain carries away less of it. Big rocks or walls along a river protect its banks.

Stopping the wind

A row of trees or a fence along a field slows the wind, so it blows away less soil and sand. To choose a solution, we compare: which one keeps the most soil in place?

Two children pour water on two tilted trays. The tray of bare soil on the left lets muddy brown water run into a cup. The tray covered with grass on the right lets almost clear water run into its cup.
Same rain, two trays: the bare soil is washed away, but grass roots hold the soil in place.

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Review game

Final assessment

To master the lesson, you need at least 60% correct answers.

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Summary

  • Landforms are shapes of the land: mountain, hill, valley, plain. Rivers, lakes and the ocean are water.
  • A map shows a place seen from above; water is often blue.
  • Earthquakes, eruptions and landslides change the land fast; erosion by water and wind changes it slowly.
  • Plants, walls and rows of trees slow down erosion; we compare solutions to choose the best one.

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