Unit 5 – Earth’s Land and Water

5

Earth’s Land and Water

In this chapter you will ...

• list and describe different kinds of land and bodies of water.

• identify where water is found on Earth and whether it is solid or liquid.

• develop a model to represent the land and bodies of water in an area.

What are the Earth’s different landforms and bodies of water?

Go Online!

Access interactive content relating to this topic on the NGScience website.

ngscience.com

What is a map? How are maps useful to people?

How can you describe the land around you?

Earth’s Landforms

The shape of the surface of the Earth can be different in many ways. In some areas the land is flat. In other areas the land may be hilly or surrounded by mountains.

The different shapes of the Earth’s land are called landforms.

What are some landforms in your area?

Amazing Fact!

A series of mountains close together is called a mountain range. The longest mountain range on Earth is the Andes in South America. It is about 7,000 km (4,300 mi) long.

Mountains

A mountain is a very high area of land that rises above the land around it. Mountains are usually steeper and taller than hills.

The highest part of a mountain is called the peak. Some mountains have peaks covered in snow for all or part of the year.

Think Deeply

You are planning an expedition to the peak of a tall mountain. What things will you pack? Why?

A Closer Look Parts of a Mountain

A mountain has different parts. Many mountains have a base, slope, snow line and a peak.

The snow line is the place on the mountain above which snow can be found all year round.

The base is the part of a mountain where the slope meets flat ground or hills. The base is usually the widest part of a mountain.

The top and highest part of a mountain is called the peak, or summit.

The slope is the side of the mountain. The slope reaches from the base to the peak.

hill

Hills, Valleys and Plains

A hill is an area of land that is higher than the surrounding land. Hills are usually not as tall or steep as mountains. Often, many hills can be found in the same area making the land look bumpy.

How are mountains and hills similar? How are they different?

Did You Know?

Scientists often classify mountains as landforms that rise 300 m (1,000 ft) above sea level. Landforms that are shorter are usually called hills.

valley plain

A valley is a low area that lies between hills or mountains. Valleys are often formed from the weathering and erosion of rivers. A plain is a large area of mostly flat land. Plains are the most common landforms on Earth.

Amazing Fact!

The Yarlung Zangbo Grand Canyon in Tibet, is the deepest canyon in the world. It was formed over millions of years by the erosion of the Yarlung Zangbo River. At some points, it is more than 6,000 m (19,685 ft) from top to bottom.

Canyons

A canyon is a deep and often narrow valley with steep rocky sides. Canyons are usually formed by the weathering and erosion of mountains by the streams and rivers that run through them. Weathering also occurs in winter, when ice breaks apart rocks. The formation of canyons from weathering and erosion takes millions of years.

Plateaus

A plateau is a large flat piece of land that is raised above the surrounding land. Plateaus can often be found between mountain peaks or at the top of canyons.

How is a plateau similar to a plain? How is it different?

AB Activities 5.1 – 5.2 Go Online!

Observe and compare the Earth’s landforms on the NGScience website. QuickCode: B7R9

Earth’s Water

Water is important to all living things. Plants, animals and people need water to survive. Without water, there would be no life on Earth.

Some of the water on Earth is fresh water. It can be found in streams, rivers and lakes.

Why is water important to all living things? Where can we find water on Earth?

Most of the water on Earth is in the ocean. The ocean contains salt water.

The fresh water and salt water on Earth can be found as liquid water or solid ice.

Salt Water on Earth

The Ocean and Seas

When viewed from space, the Earth looks like a big blue ball. The blue parts you see are the ocean. The ocean is a large body of salt water. It covers almost three-fourths of the surface of the Earth.

A great diversity of living things live in the ocean. The ocean is also very important to people for transportation and sources of food.

Salt water can also be found in seas. A sea is a smaller part of the ocean that is partly surrounded by land. In some cold areas of the Earth, parts of the ocean can freeze into sea ice. Sea ice is solid salt water.

Lagoons

A lagoon is a shallow body of salt water that is separated from the sea or the ocean by sand, rock or other natural barriers.

Fresh Water on Earth

The water in the ocean is too salty for most living things on land to use. They need fresh water. The water we drink is fresh water. Fresh water contains very little salt. On Earth, fresh water can be found in streams, rivers, lakes and ponds. In cold areas, fresh water can also be found as solid ice.

Streams and Rivers

A stream is a flowing body of fresh water. A stream starts at a high point such as a mountain or hill. As it flows downstream, it may pick up more water from melting snow or rain. It may also join other streams and grow larger to form a river. Like streams, rivers are fresh water and flow downstream. Rivers flow into lakes or the ocean.

Ponds and Lakes

Rivers often flow into lakes. A lake is a large body of fresh water that is surrounded by land. Lakes are often used by people for recreation, transport and as a source of drinking water. Much like a lake, a pond is a closed body of fresh water. Ponds are usually smaller than lakes.

How is a lagoon different from a lake or pond?

Amazing Fact!

Lake Michigan in the United States of America is the largest lake located inside one country. It is almost 500 km (300 mi) long!

Go Online!

Observe and compare the Earth’s different bodies of fresh water on the NGScience website. QuickCode: P6J2

Glaciers

A glacier is a large body of thick ice that forms from the build-up of snow over many years. Glaciers form on land. They move very slowly down mountains. When glaciers get lower down a mountain, they may melt into rivers and lakes. Some glaciers reach the ocean and form icebergs.

Icebergs

An iceberg is a large body of freshwater ice floating in the ocean. Most icebergs form when chunks of ice break off a glacier or ice shelf. A small iceberg is about the size of a bus. Some icebergs can be over 100 m (300 ft) in length.

Go Online!

Watch how glaciers form icebergs on the NGScience website. QuickCode: P7Z5

Go Online!

Scientists have discovered that human activities are causing temperatures on Earth to rise. This is causing ice at the Earth’s pole to melt faster than normal. Find out more about the effects of climate change on the NGScience website. QuickCode: N7C4

Liquid and Solid Water

There are many places where water can be found on Earth. Salt water fills the ocean. Fresh water flows from streams to rivers and lakes.

In cold parts of the Earth, water is in a frozen state as solid ice. If the temperature gets warm enough, the ice will melt into water.

In some places, streams, rivers and lakes may have water in the warm months of the year and ice in the cold months of the year. Each year, the pattern of changing from water to ice and back to water repeats.

AB Activities 5.3 – 5.4

Try This!

Look at a globe or map of the Earth with a classmate. Which parts are land? Which parts are water? What landforms can you see?

Mapping the Earth

What Is a Map?

A map is a drawing or model of an area. Some show a large area. A globe is a map of the whole planet Earth. There are also maps of countries, cities and towns.

Maps can show smaller areas such as a park, zoo or even your home.

Maps are very useful. They show us the types of things in an area. Maps also show the location of things and the distance between things.

How do people use maps? How are maps useful?

Maps can tell us the location of different landforms and bodies of water in an area.

canyon plateau

lake

hills pond

beach

mountains

river

valley

Discuss the different landforms and bodies of water on the map. Describe the locations of the landforms and bodies of water.

plain

ocean

Parts of a Map

Try This!

Find a map of a park in your area. What are the parts of the map? What does the map show? What things can you learn from the map of Silverlake Park?

Maps have different parts that help people to read and understand them. Many maps have a title that describes what the map shows.

Maps can also have a key. A key explains what different things on the map mean or represent.

Maps are much smaller than the areas they represent. A scale is a way to compare the sizes and distances of things on a map with the actual sizes and distances in real life.

AB Activity 5.5 Try This!

Draw a map to show the things around your home. Include a key and a scale.

Many cars have maps called navigation systems to provide drivers with directions.

How We Use Maps

Maps are very useful. We use maps to find the locations of things in places we do not know about.

A map can help a driver find a street or help a hiker reach a waterfall.

A map can help you find the tiger enclosure at a zoo or the sports store in a mall.

Maps also tell us the types and location of things in an area. We can use maps when visiting natural areas to help us find the location of different landforms or types of water in the area.

AB Activities 5.6 – 5.8

Use the information in the map to describe the park.

Science Words

landform mountain hill valley plain canyon plateau salt water ocean lagoon freshwater river lake glacier iceberg map

Review

1. Draw a Venn diagram to compare mountains and hills.

2. Draw a Venn diagram to compare plains and plateaus.

mountain hill

plain plateau

3. Draw a Venn diagram to compare glaciers and sea ice.

4. Use the words in the box to label the landforms.

(a)

(c) (b)

(d)

5. List two ways people use maps. 6. Which part of a map tells you the distances between objects? (a) Key (b) Title (c) Scale

glacier sea ice

canyon plateau plain valley

A Closer Look

The Grand Canyon

The Grand Canyon is a very steep and long canyon found in Arizona in the United States of America.

The Colorado River has been weathering and eroding the canyon for more than five million years! During that time, it has formed the largest canyon in the world.

The Grand Canyon is over 445 km (277 mi) in length. In some parts, it is almost 1,800 m (6,000 ft) deep and up to 28 km (18 mi) across. Weathering and erosion continue to make the Grand Canyon deeper and wider, but much too slowly for us to see from day to day. What do you think the Grand Canyon will look like a million years from now?

Go Online!

Take a virtual field trip to the amazing Grand Canyon on the NGScience website. QuickCode: B2B6