Let's Do Science 2 – Textbook B

Pri ma ry 2 Textbook

B

Aligned to the Next Generation Science Standards

Pri ma ry 2 Textbook

B

The 5E Model – Guided Inquiry The Let’s Do Science series is based on the Biological Sciences Curriculum Study (BSCS) 5E teaching and learning instructional model. The 5E model is centered on the idea that students understand science concepts best by using prior knowledge to pose questions and find answers through guided inquiry.

This hands-on approach, integrated with engineering and design skills, has students learn science by doing science. Teachers guide the learning process and are able to assess student performance by evaluating student explanations and the application of newly acquired knowledge and skills.

Engage

The Engage phase of the 5E model provides students with the opportunity to demonstrate their prior knowledge and understanding of the topic or concept. Students are presented with an activity or question which serves to motivate and engage students as they begin the lesson. Teachers identify and correct any misconceptions and gather data from students which will guide informed teaching and learning.

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Essential to stimulating and engaging students is the use of mixed media such as colorful photos, illustrations and diagrams found throughout the textbooks and activity books. Let’s Do Science also includes extensive digital resources such as narrated videos, interactive lessons, virtual labs, slideshows and more.

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Explore

This phase encourages exploration of concepts and skills through handson activities and investigations. Students are encouraged to work together and apply various process skills while gaining concrete, shared learning experiences. These experiences provide a foundation for which students can refer to while building their knowledge of new concepts. This studentcentered phase comes before formal explanations and definitions of the concept which are presented by the teacher.

Explain

This phase follows the exploration phase and is more teacher-directed.

Students are initially encouraged to draw on their learning experiences and demonstrate their understanding of the concept through explanations and discussion. After the students have had the opportunity to demonstrate their understanding of the concept, the teacher then introduces formal definitions and scientific explanations. The teacher also clarifies any misconceptions that may have emerged during the Explore phase.

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Elaborate

In the Elaborate phase, students refine and consolidate their acquired knowledge and skills. Opportunities are provided for students to further apply their knowledge and skills to new situations in order to broaden and deepen their understanding of the concept. Students may conduct additional investigations, share information and ideas, or apply their knowledge and skills to other disciplines.

Evaluate

This final phase includes both formal and informal assessments. These can include concept maps, physical models, journals as well as more traditional forms of summative assessment such as quizzes or writing assessments.

Students are encouraged to review and reflect on their own learning, and on their newly acquired knowledge, understanding and skills.

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Let’s Do Science Let’s Do Science is based on the United States Next Generation Science Standards (NGSS). The series consists of full-color textbooks and full-color activity books for Grades K to 6.

Birds

Birds are anim covered in feat legs and two w their wings to f

Birds ha shapes shape o bird to g

Let’s Do Science engages students with a highly visual presentation of the disciplinary core ideas in the textbooks and places an emphasis on applying scientific knowledge using NGSS practices through numerous scientific investigations. Let’s Do Science sees engineering as an essential element of science education and as such is tightly integrated into both the textbooks and activity books.

The Let’s Do Science textbooks include the following features:

Think Deeply

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Topic-related questions for group discussion aimed at deepening students’ understanding of the topic.

In the Field

If you love plants of all shapes and sizes, you might want to be a horticulturist. A horticulturist is a scientist that specializes in growing plants for people to use.

Horticulturists can also use their knowledge of plants and soil to help manage and protect natural areas like parklands or nature reserves.

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Horticulturists use their knowledge of plants to help farmers improve the fruits, flowers and vegetables they grow.

Engineer It! Goes beyond inquiry by encouraging students to design, model and build to engineer solutions to defined problems.

In the Field Inspirational sciencerelated professions to stir interest in sciencerelated careers.

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A Closer Look

Rainforest Layers

Tropical rainforests are the most diverse land habitats on Earth. They are warm all year round and lots of rain means lots of water for living things. There is another reason tropical rainforests are so diverse – layer 53 s.

Tropical rainforests have four main layers – the forest floor, understory, canopy and emergent layer.

Each layer forms a habit at for different types of plants and animals.

You can think of a tropical rainforest as four habitats in one!

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A Closer Look Invokes enthusiasm in science by presenting interesting topics beyond the syllabus.

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Amazing Fact!

Interesting facts to build interest and enthusiasm.

Birds reproduce by laying eggs. Parents often care for their young when they hatch from the eggs.

mals with a body thers. They have two wings. Many birds use fly.

Did You Know?

ave beaks of all and sizes. The of the beak helps the get the food it needs.

Did You Know?

All birds have feathers and wings, but not all can fly. Flightless birds include penguins, emus, ostriches and cassowaries.

AB

Try This!

Activity 2.3

Optional hands-on activities to be conducted in groups or at home.

What are the characteristics of birds?

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Science Words

volcano erupt magma lava earthquake tsunami

flood landslide thunderstorm wildfire hurricane

4. What process is show n in the pictu

tornado weathering erosion deposition land reclamation

Review

1.

Extra information to build students’ knowledge base of the current topic.

Which best describes the process when soil and rocks fall from mountains and hills. (a) Tsunami (b) Wildfire (c) Landslide

2. Which best describes the process when hot molten rock flows onto the Earth ’s surface? (a) Earthquake (b) Volcanic eruption (c) Thunderstorm

re?

(a) Erosion (b) Weathering (c) Deposition

5. Describe the differ ence between erosion and weat

6. Use the words in the box to erosion

hering.

label the picture.

deposition

Discussion

8. List three processe s that change the shap e of the land rapidly.

Emergent Layer 108

Links students to the Let’s Do Science Activity Book at the appropriate juncture.

(b)

(a)

7. Describe the differ ence between a lands lide and weathering.

3. What can cause a tsunami? (a) Earthquakes and volcanic eruptions (b) Landslides (c) Hurricanes and torna does

AB Activity

9. List three process that change the shap e of the land slowly.

10. Describe two ways people can slow or preve nt changes to the shape of the land.

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Canopy

Topic-related questions and situations for class discussion to build a deeper understanding of topics.

Understory

Review Forest Floor

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Topical questions at the end of each chapter for formative assessment.

Science Words Lists the essential science vocabulary covered in each chapter.

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Contents Unit 5 – Earth’s Land and Water Earth’s Landforms Earth’s Water Salt Water on Earth Fresh Water on Earth Liquid and Solid Water Mapping the Earth Review

Unit 6 – Forces and Motion

Regal Education Inc Position and Motion Forces and Motion Types of Forces Review

Unit 7 – Properties of Matter What Is Matter?

States of Matter Describing and Measuring Matter Properties of Materials Review

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2 4 12 14 17 22 24 34

38 40 44 48 54

56 58 60 68 72 78

Unit 8 – Changes to Matter Changing Matter Heat and Matter Review

Unit 9 – Heat and Electricity

82 84 92 100

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Sources of Heat Using Heat Heat and Temperature Using Electricity Simple Circuits Review

106 107 110 112 114 118 120

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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.

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

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

What is a map?

How are maps useful to people?

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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.

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

What are some landforms in your area?

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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.

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

Why?

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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.

A Closer Look

Parts of a Mountain A mountain has different parts.

Many mountains have a base, slope, snow line and a peak.

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

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

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

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.

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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. hill

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.

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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.

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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.

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Go Online!

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

QuickCode: B7R9

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

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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?

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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.

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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.

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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.

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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.

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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.

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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.

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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

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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.

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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

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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

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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

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Mapping the Earth What Is a Map? 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?

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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?

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

canyon

plateau

lake pond

hills beach

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mountains

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

river

valley

plain

ocean

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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.

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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

Try This!

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

Activity 5.5

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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.

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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

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Use the information in the map to describe the park.

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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. mountain

hill

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

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plateau

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

sea ice

4. Use the words in the box to label the landforms. canyon plateau plain valley (a)

(b)

(c)

(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 35

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.

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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.

Go Online!

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

QuickCode: B2B6

What do you think the Grand Canyon will look like a million years from now?

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6

Forces and Motion

In this chapter you will ...

• describe the position and motion of objects.

• identify pushes and pulls.

• distinguish and describe contact and non-contact forces.

• describe how friction, magnetic force and gravity can affect the motion of objects.

How can we describe the position and motion of objects?

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

How do forces affect motion?

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What is the difference between contact and non-contact forces?

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Position and Motion When describing the world around us it helps to know where things are and how they are moving.

Describing Position

Regal Education Inc The position of an object is its location. We can describe the position of an object by saying where it is relative to other objects.

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Let’s describe the positions of some of the objects in the room.

The plant is to the left of the computer.

The computer is between the plant and the books.

The clock is above the plant.

The keyboard is in front of the computer.

What are some other ways to describe the positions of the objects?

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Activity 6.1

Try This!

With a partner, describe the position of your desk relative to other classroom objects.

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Describing Motion

Go Online!

Observe and describe different objects in motion on the NGScience website.

QuickCode: F1T2

When an object is in the process of changing its position, it is moving.

We say it is in motion. We can describe the motion of an object in different ways.

We can describe motion by talking about the path along which it is moving.

Things can move in a straight line.

They may roll, turn or spin. Things can move up and down, back and forth or round and round.

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Describe the different ways things move in a playground.

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We can also describe the speed of an object in motion. Speed is how fast or slow it is moving.

AB

Activity 6.2

Describe the motion of passengers on a roller coaster during a ride. How does the speed of motion change?

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Try This!

Choose a ball sport.

Describe how forces are used to change the motion of the ball.

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Try This!

Forces can make an object change shape.

Plan and conduct an investigation to see how different forces can change the shape of a piece of clay.

Forces and Motion

A force is a push or a pull. A push is when you press something away from you. A pull is when you tug something closer to you.

Pushes and pulls can change the movement of objects.

Regal Education Inc A push force applied to a wheelbarrow makes it move.

A suitcase moves when you use a pull force to drag it behind you.

In what ways can forces change the movement of an object?

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Sometimes, like when riding a bicycle, we use a push and a pull.

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We use pushes and pulls when we vacuum a floor or open and close a door.

What push and pull forces can you observe around you? How do they make things move?

AB

Activities 6.3 – 6.5 45

Force can make things move in different ways.

How do forces change the movement of a ball during a soccer match?

Regal Education Inc Try This!

With a partner, use forces to make marbles move in different ways. Describe the forces you used and how it affected the motion of the marbles.

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During a game of soccer, a kick starts the ball moving.

As players pass the ball, it speeds up, slows down and changes direction. When the goalkeeper catches the ball, it stops moving.

As we can see from a soccer match, forces can make an object: • Start and stop moving.

• Speed up and slow down.

• Change direction.

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Activity 6.6

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Types of Forces There are different types of forces.

Forces that are applied when objects are touching are called contact forces. Hitting a ball and pulling on a rope are contact forces.

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Some forces can be applied when objects are not touching. These forces act at a distance and are called non-contact forces.

Take a magnet and hold it above an iron nail. The force of the magnet is applied to the nail without touching it. The force of a magnet is a noncontact force.

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Friction Take a wooden block and slide it along the floor. The wooden block moves when you push it. It then slows down and stops.

What causes the block to slow down and then stop?

Try This!

Given the same force, would a wooden block move further on a wooden floor or carpet?

Plan and conduct an investigation to find out.

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Friction is a contact force that slows down moving objects. It occurs when two objects are in contact with each other. The friction between the surface of the block and the surface of the floor caused the block to slow down and stop.

Think Deeply What are some examples where friction can be helpful? When can friction cause problems?

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Magnetic Force Think Deeply

What do you notice about the objects attracted to the magnet?

Why are the paper clips attracted to the magnet?

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In small groups, gather some objects in your classroom that you think will be pulled by a magnet. Use a magnet to test each object.

Engineer It! Design and build a toy car that can move up and down a ramp using magnetic force.

A magnet is an object that can pull certain types of metal – it has magnetic force. Magnetic force is a non-contact force. It works over a distance. A magnet does not need to be touching the object it pulls.

What are some ways magnets are used by people?

AB

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Activity 6.7

A Closer Look

The Poles of a Magnet

Magnets have two poles – a north pole and a south pole.

The pulling force of a magnet is strongest at the poles.

Magnets can attract (pull) or repel (push away) other magnets.

When the opposite poles of two magnets are brought together, the magnets attract each other.

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When the like poles of two magnets are brought together, the magnets repel each other.

Try This!

Take two bar magnets and put the poles together in different ways. Describe what you observe.

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Gravity Use your finger to trace the path the basketball will take as it leaves the boy’s hands.

What force causes the ball to move up into the air?

What force will cause the ball to fall to the ground?

All objects attract other objects.

This force is called gravity.

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The boy used a push force to throw the basketball and the Earth’s gravity pulled the ball down to the ground.

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When you drop a pencil, it falls to the ground. When a skydiver leaps from a plane, they are pulled to the Earth’s surface.

All of the objects on Earth are being pulled downwards towards the center of the Earth by gravity. The Earth’s gravity keeps everything on its surface and stops things from floating away.

AB

Try This!

In small groups, go outside and throw a ball into the air. Describe how forces, including gravity, affect the motion of the ball.

Activity 6.8

Regal Education Inc Think Deeply In what way is gravity similar to magnetic force?

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Science Words

position motion speed force

push pull contact force non-contact force

friction magnetic force gravity

Review

1.

Which best describes position? (a) How far an object has moved. (b) The location of an object. (c) How an object moves.

2.

Which best describes speed? (a) The location of an object. (b) The path along which an object moves. (c) How fast or slow an object moves.

3.

Which best describes motion? (a) The movement of an object. (b) The speed of an object. (c) The force of an object.

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4. What is a force?

5. List two activities where you use a push force.

6. List two activities where you use a pull force.

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7. List five ways forces can change the motion of an object.

8. Describe and provide an example of a contact force.

9. Describe and provide an example of a non-contact force.

10. What force pulls the pins to the magnet?

Regal Education Inc 11. True or false. Friction helps things move.

12. What force is pulling the boy to the water?

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7

Properties of Matter

In this chapter you will ...

• describe and classify matter.

• test and describe the properties of materials.

What are some properties of matter and materials?

Go Online!

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

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What properties of objects make them suitable to their use?

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What Is Matter?

Everything around you is matter. The things you see, touch, smell and taste are matter. The water you drink is matter. The air you breathe is matter too. Matter is anything that has mass and takes up space.

What matter can you see around you? Is there matter around you that you cannot see?

The soft toy takes up space in the bucket. The beach ball takes up more space than the toy car.

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Water, rocks and air are matter.

Some matter can have more mass than other matter. Using a balance, we can see that the teapot has more mass than the mug.

Try This!

Compare some different objects in your classroom. What words can you use to describe each object?

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States of Matter Compare the things on these pages. How are they different?

Matter can come in different states – solids, liquids and gases.

The toy blocks are solid matter.

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Water is liquid matter.

The air inside the balloon is gas.

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Activity 7.1

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Solids Take an eraser and roll it on a table. Does the shape of the eraser change?

Regal Education Inc Think Deeply

Find three things in your classroom that are solid matter. Tell how you know they are solid matter.

The eraser, like most of the things you see around you, is solid matter.

Solid matter has a shape of its own.

The amount of space solid matter takes up does not change.

When you rolled the eraser on the table, the shape and amount of space taken up by the eraser did not change.

Ice is solid water.

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The toy blocks are solid matter. They keep the same shape when they are in the container or spilled out.

The amount of space the toy blocks take up also stays the same.

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Activities 7.2 – 7.3

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Liquids

Try This!

Pour some water between different containers. Describe what happens to the shape of the water.

Think Deeply

What happens to the shape of the water as the girl pours it from one container to another?

The colored water the girl is pouring is liquid matter.

As the liquid is poured from one container to another, its shape changes.

Liquid matter does not have a shape of its own. A liquid flows to take the shape of the container it is in.

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A pile of sand appears to change shape as it is poured from one container to another.

Is sand a solid or a liquid?

Explain your answer.

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Pour some water into a beaker.

Observe how much space the water takes up. Pour the water into another container, then pour it back into the beaker. What do you notice?

Like solid matter, the amount of space taken up by a liquid does not change.

Tell how you know milk is a liquid.

Did You Know?

The amount of space something takes up is called volume. You can measure the volume of liquids with a measuring cup or beaker.

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Activities 7.4 – 7.5

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When air is let out of a balloon, it spreads out to fill the room.

Gases Blow up a balloon and hold it closed. Observe the shape and size of the balloon.

Slowly let the air out of the balloon. What do you observe about the size and shape of the balloon?

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The air in the balloon is a gas. Gas is matter that does not have a shape of its own. It spreads out to fill the space it is in.

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Try This!

Blow some soap bubbles.

Talk about the shape and size of the bubbles. What happens to the air in the bubbles when they pop?

Think Deeply

Gases can also change in the amount of space they take up.

A scuba tank can hold enough air for a diver to breathe underwater for more than an hour.

Why is this so?

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When you let the air out of the balloon, it spreads out to fill the room. It takes up more space.

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Properties of Matter Describing and Measuring Matter Describing Matter

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We can describe and compare the objects around us by observing their properties.

We can observe some properties, such as shape, size and color, using our sense of sight.

What are some of the properties of the objects on these pages?

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Try This!

Use your sense of touch to observe different objects in your classroom. Describe the texture of each object.

You can also observe the properties of objects using your sense of touch.

Texture is how an object feels.

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An object might feel hard or soft.

It may feel rough or smooth.

AB

Activity 7.6

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Measuring Matter Try This!

Use a balance to compare the weight of the objects on your table. Order the objects from the lightest to the heaviest.

Compare the soft toy and the soccer ball. Which object has more mass?

How do you know?

There are many properties of objects you can test or measure. A balance is a tool you can use to measure the weight of an object.

Weight is how light or heavy something is.

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The soccer ball is heavier than the soft toy.

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Activity 7.7

Rulers and tape measures can be used to measure the length of objects in centimeters or inches.

You can test if an object is magnetic by holding it near a magnet. A magnetic object is pulled by the magnet.

You can test the buoyancy of an object by placing it in water. Some objects stay on top, or float, when placed in water. Other objects fall to the bottom, or sink, when placed in water.

Regal Education Inc The nails are magnetic.

The rubber duck floats. The marbles sink.

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Activities 7.8 – 7.9 71

Properties of Materials Go Online!

Learn about different materials and their properties on the NGScience website.

QuickCode: P9G5

Try This!

Find objects in your classroom that are made of two or more different materials.

How are the materials suited to how the objects are used?

We use different materials to make different objects. Some materials include metal, glass, wood, plastic, rubber and fabric.

Different materials have different properties. When we make objects, it is important to choose materials that have properties that are suited and safe for how the object is used.

What materials are used to make these objects? How are the properties of the objects suitable to their use?

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The strength of a material is how much it can be pulled apart or Strength goes here. pushed together without breaking.

Flexibility goes here.

Hardness is how much a material can withstand scratching.

Regal Education Inc Why is metal a suitable material for making things such as bridges, hammers and nails?

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Flexibility is how much a material can bend without breaking. The rope is made of material that is flexible and strong.

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What are some other objects that are flexible? What materials are they made of?

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Transparency is how much light can pass through a material. The glass jars are transparent. You can see the food inside the jars clearly.

The white curtains allow some light to pass through – they are translucent.

You can see through the curtains, but not clearly.

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A material that does not allow any light to pass through it is opaque. You cannot see through opaque materials.

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Absorbency is how much liquid a material can hold.

Sometimes, like when cleaning a spill, it is useful for a material to be absorbent.

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Other times it is helpful to use materials that are not absorbent, like the plastic used to make an umbrella and a raincoat.

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Activities 7.10 – 7.11

Discuss the materials used to make these objects.

How are the materials suitable and safe for how the objects are used?

Engineer It! Design and build your own object. Select materials based on how suitable and safe they are for the function of the object.

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Science Words

matter solid liquid gas texture weight

magnetic buoyancy float sink strength hardness

flexibility transparency transparent translucent opaque absorbency

Review

1. Which best describes matter? (a) Everything that we can see. (b) Everything that has mass and takes up space. (c) Everything we can feel.

2.

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True or false. (a) Solid matter has a shape of its own. (b) Liquid matter has a shape of its own. (c) Gases spread out to fill the container they are in.

3. What property tells you how light or heavy an object is? (a) Weight (b) Buoyancy (c) Strength

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4. What property tells you if an object floats or sinks? (a) Flexibility (b) Buoyancy (c) Transparency 5. What property tells you how much light can pass through a material? (a) Transparency (b) Weight (c) Hardness 6. What property tells you how much liquid a material can hold? (a) Transparency (b) Strength (c) Absorbency

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7. List some properties of each object. (a) (b)

(c) (d)

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In the Field

If you love art and science, you might want to be an architect. An architect designs and draws plans for structures like buildings and houses.

Architects know a lot about materials and their properties. They need to make sure the materials used to build the structures they design are safe and suitable for their function.

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Being an architect can be a very rewarding job. You design the places where people live, work or play. If you were an architect, what would you design?

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8

Changes to Matter

Regal Education Inc How can an object made of a small set of pieces be disassembled and made into a new object?

In this chapter you will ...

• describe ways in which matter can change.

• describe how an object made of a small set of pieces can be disassembled and made into a new object.

• observe, test and describe how heat can change matter.

• list some changes caused by heating or cooling that can be reversed and some changes that cannot be reversed.

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Go Online!

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

How does matter change when it is heated or cooled?

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Changing Matter

How Can We Change Matter?

We can change matter in many ways.

You can change a sheet of paper by folding or cutting it to make a new object.

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What are some other ways we can change matter?

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You can change matter by breaking it into smaller pieces, like cutting a loaf of bread.

You can also change matter by putting smaller pieces together to make a big object, like assembling the parts of a toy.

Try This!

Does the mass of solid matter change when it is cut into pieces? Conduct an investigation to find out.

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Activity 8.1

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Sometimes when we change matter, we can also change it back to its original form. You change matter when you assemble blocks to build a toy house. You can also take apart the toy house, leaving the blocks again.

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Other times, matter that is changed cannot be changed back to its original form.

When you chop firewood, you cannot change it back into a log.

When you make a fruit smoothie, you cannot change the smoothie back into the fruits used to make it.

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Activity 8.2

What are some other examples where matter is changed and cannot be changed back?

Regal Education Inc Try This!

Take a piece of scrap paper and change it in a way that it can be changed back. Change the paper again in a way that cannot be changed back.

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Putting Together and Taking Apart Different objects can be made by putting smaller objects together. The new objects can have different characteristics, even though they were made of the same set of pieces.

Regal Education Inc Think Deeply Imagine you are a builder about to build a new house. Which part of the house would you build first? Why?

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Many bricks can be put together to make the walls of a house.

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Regal Education Inc Think Deeply

Imagine you are a builder about to demolish an old house.

Which part of the house would you take down first? Why?

An object such as a house is made of many small pieces. The pieces can be disassembled and made into new objects. The bricks used to build the walls of a house can be disassembled.

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The disassembled bricks can be assembled again and made into new objects.

They could be used to make a garden path or to build a barbecue pit.

The new objects can have different characteristics, even though they were made of the same set of pieces.

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Activity 8.3

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Heat and Matter Go Online!

Learn about different materials and their properties on the NGScience website.

QuickCode: E1X9

Changing Temperature Temperature is how hot or cold something is. When matter is heated, its temperature increases.

When matter is cooled, its temperature decreases.

Heating and cooling matter can cause it to change from one state to another.

What change in state occurs when solid matter is heated?

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Butter melts when it is heated.

Solid to Liquid

When metal is heated, it changes into a liquid.

When matter is heated, its temperature increases. This can cause matter to change from solid to liquid. This process is called melting.

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Some matter, like ice, will melt at room temperature. It changes from solid ice to liquid water. Other matter requires more heat to start melting.

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Try This!

Plan and conduct an investigation to observe how heating and cooling changes a block of chocolate.

Describe the changes you observe.

Liquid to Solid When matter is cooled, its temperature decreases. This can cause matter to change from liquid to solid. This process is called freezing.

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Placing water in a freezer decreases its temperature. It changes from liquid water to solid ice.

What causes a wax candle to melt and freeze?

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Activity 8.4

Reversible Changes The change from liquid water to solid ice is an example of a reversible change.

When water is cooled, it changes to ice. When ice is heated, it changes to water.

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What are some other examples of reversible changes that occur when matter is heated and cooled?

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A Closer Look

Liquid to Solid to Gas and Back Again Ice is water in a solid state. When ice is heated, it melts and becomes liquid water. If water is heated, it also changes state – it evaporates into a gas called water vapor.

What happens when water vapor is cooled?

Regal Education Inc Go Online!

Visit the NGScience virtual laboratory to watch and learn how matter changes state.

QuickCode: F6Y1

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When water vapor cools, it changes back into liquid water. This process is called condensation.

When the liquid water is cooled, it will freeze and change to solid ice.

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Irreversible Changes Sometimes when matter is changed by heating or cooling, it cannot be changed back.

The change is irreversible.

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Think Deeply What are some irreversible changes that occur when you prepare and eat your breakfast, lunch and dinner?

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When you fry a raw egg, you use heat to change the matter.

The egg can never be changed back to a raw egg.

Cooking toast makes it hard and crispy. Cooling the toast will not change it back to soft bread.

The change is irreversible.

Popping popcorn and burning paper and wood are also irreversible changes.

Go Online!

Learn more about reversible and irreversible changes on the NGScience website.

QuickCode: J4R5

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Activities 8.5 – 8.6

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Science Words

temperature melting freezing

reversible change irreversible change

Review

1. Describe two ways you can change matter.

2. Which process occurs when a liquid changes to a solid? (a) Melting (b) Flowing (c) Freezing

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3. Which process occurs when a solid changes to a liquid? (a) Pouring (b) Melting (c) Freezing 4. True or false. (a) Matter can change state when it is heated. (b) Matter can change state when it is cooled. (c) Water changing to ice is a reversible change.

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5. Label the changes as ‘reversible’ or ‘irreversible’. (a)

(b)

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(c)

(d)

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A Closer Look

3D Printing Imagine being able to print an object just like you can print words and pictures on paper.

Well, now you can! A 3D printer heats and cools materials to build objects from a design.

Regal Education Inc Many 3D printers build objects made of plastic.

The plastic is heated to become a liquid. The liquid plastic is applied layer by layer to build the object. As each layer cools, it becomes solid plastic again.

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3D printers are used to make many types of objects. They are used to make body parts and organs, replacement parts for cars and airplanes, toys and even food.

Regal Education Inc Engineers often print models of their designs to test them before making the real object. How is this useful?

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9

Heat and Electricity What are some sources of heat?

How do people use heat?

Regal Education Inc In this chapter you will ...

• list sources of heat and describe how they are used by people.

• describe how heat moves between objects.

• list the ways people use electricity.

• describe how electricity moves in a circuit.

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What are some ways people use electricity?

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Go Online!

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

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What Is Heat?

Heat is a form of energy that makes things feel warm. When you place a glass on cold water in the Sun, it gains heat energy and feels warmer.

When you place a warm glass of water in a refrigerator, it loses heat energy and feels cooler.

What happens to an object when it loses heat energy?

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1 06

Sources of Heat A source of heat is something that produces heat.

What is the main source of heat on Earth?

On Earth, the Sun is our main and most important source of heat. The heat from the Sun warms our whole planet and all of the living and non-living things on it.

Think Deeply What would the Earth be like if the Sun was further away? What if it was closer?

If there was no heat from the Sun, there would be no life on Earth.

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What are some other sources of heat?

Think Deeply Touch your palms together and rub your hands back and forth.

Notice that your hands get warmer. What type of force produces the heat?

There are many other sources of heat. Burning wood, gas and oil are sources of heat. When these things burn, they produce heat.

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Many appliances and devices in our homes are sources of heat too.

Ovens, kettles and toasters are sources of heat.

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Clothes dryers, irons and hair dryers are sources of heat too.

How is heat used by people?

What is the source of heat?

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Activity 9.1

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Using Heat Engineer It! In small groups, design and build a solar hot water system. Use a thermometer to test your water heater. Compare the water temperature with other groups.

People use heat in many different ways. The heat from the Sun keeps us warm. We also use the heat from the Sun to dry our clothes.

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A solar water heater uses the heat from the Sun to warm water for use around the house.

We use heat in many ways in and around our homes. In the colder months of the year, we often use heaters to warm our homes.

We use heat in barbecues, ovens, and stove tops to cook our food. We heat water to boil food and make hot drinks.

We use heat to dry and iron our clothes.

We use heat to warm water for baths, showers and washing dishes.

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Activity 9.2

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Heat and Temperature Try This!

Place a glass of water outside. Measure the temperature of the water four times throughout the day. Tell how the temperature of the water changed.

Temperature is a measure of how hot or cold something is. The more heat an object gains, the higher its temperature.

We can get a rough indication of temperature by using our sense of touch. To accurately measure temperature, we can use a thermometer. A thermometer is a device that measures temperature in degrees Celsius (oC) or degrees Fahrenheit (oF).

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Heat can travel through solids, liquids and gases. Heat always flows from hot objects to cool objects. As the cool object absorbs the energy from the hot object, it becomes warmer. Heat continues to move in this way until the temperature of both objects is the same.

Within an object, heat also moves from hot to cold.

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Activities 9.3 – 9.5

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Explain what will happen to the wax and thumb tacks attached to the metal rod.

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Think Deeply Think about the function of these appliances and the tasks they perform.

How were these tasks achieved in the past before electricity was discovered?

Using Electricity Electricity is very useful to people.

Many appliances in our homes and schools need electricity to work.

Light bulbs, ovens, refrigerators, washing machines and kettles all use electricity produced in power stations.

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Batteries Some devices, such as mobile phones, flashlights and many watches, get electricity from batteries.

Batteries come in different shapes and sizes. Some batteries can be used over and over again. Others must be disposed of once they no longer produce electricity.

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Activity 9.6

Amazing Fact!

Some electric cars are powered by almost 10,000 small batteries.

They are able to travel hundreds of kilometers before the batteries need to be re-charged.

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Saving Electricity Try This!

Make a poster about how you and your family can save electricity at home. Show your poster to your friends.

We waste electricity when it is used by appliances that we are not using.

Saving electricity helps to make electricity available to everyone. It also saves money.

Here are some simple ways you can save electricity at home and at school: • Turn off lights and open curtains and blinds during the day.

• Turn off appliances and heaters when you are not using them.

Regal Education Inc • Use low-energy light bulbs.

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Activity 9.7

Electrical Safety Electricity can be dangerous if it is not handled correctly and safely. Always follow these electrical safety tips: • Do not put too many plugs into one socket or power board.

• Do not put anything inside a socket other than a plug.

• Keep water away from electrical sockets and appliances.

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• Do not play or run around electrical cables.

• Always use an electrician for any electrical repairs.

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Activity 9.8

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Simple Circuits Go Online!

An electric circuit is the path along which electricity moves. In a circuit, the electricity travels from a source, through an appliance or device and back to the source of electricity again.

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Build and test virtual electric circuits on the NGScience website.

QuickCode: M3W9

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A simple circuit consists of a battery, wires and an appliance such as a light bulb. A switch can also be used to control the flow of electricity.

The appliance in a circuit will only work when there is a complete path along which the electricity can flow.

When a switch is in the ‘off’ position or there is a break in the circuit, the circuit is open and the appliance will not work.

Did You Know?

Some materials, such as metal, allow electricity to pass through them easily. They are electrical conductors.

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When a switch is in the ‘on’ position and there is no break in the circuit, the circuit is closed and the appliance will work.

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Other materials, such as plastic and wood, do not allow electricity to pass through them easily. They are electrical insulators.

Activities 9.9 – 9.10

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Science Words

heat temperature thermometer

electricity battery electric circuit

Review

1. What is the main source of heat on Earth?

2. List two sources of heat.

3. List two ways you use heat at home.

4. What is the temperature shown on each thermometer in degrees Celsius?

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(a)

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(b)

(c)

5. List two appliances in your home that use electricity produced in power stations.

6. List two devices in your home that use batteries.

7. True or false. (a) You should keep lights on even when not using them. (b) Using low-energy light bulbs can help save electricity.

8. List three things you can do to stay safe from electricity.

9. What is an electric circuit?

10. In which circuit will the light bulb turn on?

Tell how you know.

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(a)

(b)

(c)

(d)

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Special thanks to: Matthew Cole, Daniel Cole, Wang Hui Guan Joseph Anderson, Halle Taylor-Pritchard, Sophie Taylor-Pritchard, Tejal Thakur Varasinun Mathanattapat, Kanungnit Pookwanmuang, Saijit Lueangsrisuk Original Illustrations: Natchanuch Nakapat, graphicsRF, Blue Ring Media and Interact Images Royalty-free images: Shutterstock, Adobe Stock