Next Generation Science Level 4 - Activity Book B

Science for the Next Generation

Science G ra d e F ou r

Activity Book

B

Next Generation Science Next Generation 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.

Next Generation 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. Next Generation Science sees engineering as an essential element of science education and as such is tightly integrated into both the textbooks and activity books.

The Next Generation Science activity books include the follow features:

AB Activity

3. Use the skipping

Activity 4.4

Activities and investigations related to concepts and topics covered in the Next Generation Science Textbook.

Observations Record the times take Activity

taken in the table below.

Breathing Rate (Breaths/min)

Pulse Rate (Beats/min)

Resting

Make a Prediction

Skipping 15 s

your breathing rate?

Skipping 30 s affect 2. How will exercise

your pulse rate?

Rest 5 min

Procedure

on your chest. Use 1. Place your hand how many the stopwatch to time 30 seconds. breaths you take in r of breaths by Multiply the numbe ng rate. two to get your breathi by gently placing 2. Locate your pulse side of your neck. two fingers on the to count how Use the stopwatch beats in 30 many times your pulse number of the Multiply seconds. your pulse rate. beats by two to get

Engineer It!

93

Engineer 92It!

Model Animal Structures

Design, draw and label your solution.

A train engineer from Japan had a problem.

The high-speed train he designed made too much noise when traveling at high speeds.

As a keen bird-watcher, he used inspiration from the shape of a kingfisher’s beak to design and build a solution for the nose of the high-speed train. It was a success!

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

Now it’s your turn. Identify a problem people face.

Use your knowledge of the external and internal structures of animals to design and build a solution to the problem.

The Problem Define a problem affecting people.

The Solution Analyze and Interpret

Explain your solution to the problem.

Present your model to other groups. Evaluate the effectivene ss of your model. How could it be improved?

76

table.

2. Complete the

Review

Review

2.

5. Rest for five minutes

• skipping rope

affect 1. How will exercise

2.

s. Repeat Steps 1 and

to skip for 30 second

2. . Repeat Steps 1 and

Materials • stopwatch

s. Repeat Steps 1 and

rope to skip for 15 second

rope 4. Use the skipping

s

Your Heart and Lung

ns es and Functio Animal Structur

an eagle. e. al structures of the eagle surviv structure helps 1. Label the extern describe how each Use the table to

Functions

Structure

77

lungs

skeleton Pull on bones to

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

l to move enable the anima its parts.

gills

intestines l’s body. hout the anima

Pumps blood throug

Structure

Function

res internal structu l’s external and le of how an anima animal survive.

3. Provide an examp part of a system that helps an er as function togeth

ry function of the

4. What is the prima

brain?

85

84

ii

Contents Unit 6 - Processes That Shape the Earth

2

Unit 7 - Mapping the Earth’s Surface

59

Unit 8 - Using Earth’s Resources

86

Unit 9 - Energy and Motion

104

Unit 10 - Waves and Information

133

iii

Activity 6.1

Minerals and Their Uses 1. What are minerals and where are they found?

2. Describe how each mineral is used by people. (a) copper

(b) talc

(c)

2

salt

(d) diamond

(e) iron ore

3. Why are minerals important to plants and animals?

4. How do plants get the minerals they need?

5. List two minerals used by humans. Describe how they help the body.

3

Activity 6.2

Properties of Minerals Materials • assorted minerals

• hand lens

• porcelain tile

• flashlight

• metal nail

Procedure 1. Your teacher will set up mineral testing stations around the classroom.

Each station is set up to test a specific property of the minerals.

2. Conduct the test and record your observations. Then move on to the next station.

4

Color and Luster Shine the flashlight on the mineral and observe it closely using the hand lens.

Record your observations.

Streak Take a mineral and firmly strike it along the surface of the porcelain tile. Observe the mark it makes on the tile and record your observations.

Hardness Take the metal nail and scratch the mineral.

Observe how the mineral is scratched and record your observations.

Observations Mineral: Color

Luster shiny

dull

Streak (describe the color)

Hardness (1 – scratches easily, 5 – does not scratch)

1

2

3

4

5

5

Mineral: Color

Luster shiny

dull

Streak (describe the color)

Hardness (1 – scratches easily, 5 – does not scratch)

1

2

3

4

5

Mineral: Color

Luster shiny

dull

Streak (describe the color)

Hardness (1 – scratches easily, 5 – does not scratch)

1

6

2

3

4

5

Mineral: Color

Luster shiny

dull

Streak (describe the color)

Hardness (1 – scratches easily, 5 – does not scratch)

1

2

3

4

5

Mineral: Color

Luster shiny

dull

Streak (describe the color)

Hardness (1 – scratches easily, 5 – does not scratch)

1

2

3

4

5

7

Mineral: Color

Luster shiny

dull

Streak (describe the color)

Hardness (1 – scratches easily, 5 – does not scratch)

1

2

3

4

5

Analyze and Interpret 1. Did any minerals have a different streak than their color? If so, why is streak a more useful property of minerals to measure?

2. Rank the minerals you tested by their hardness.

3. Why is it useful to know the properties of minerals?

8

Activity 6.3

Comprehension – Types of Rocks 1. Use your textbook to help you fill in the blanks. (a) There are three main types of rocks –

and

(b)

(c)

, .

form when molten rock, called , cools beneath the Earth’s surface.

With enough heat and pressure, magma can break through the

Earth’s surface as

.

(d)

form when minerals and organic

particles settle in layers on or just below the Earth’s surface. (e) is the process of the particles settling. Over millions of years the sediment layers are slowly compacted and bind together to form rock in a process called (f)

.

form deep below the surface of the

Earth through a process called

.

(g) Metamorphosing occurs when rock is subject to immense

and

.

9

2. Use the three-part Venn diagram to compare and contrast the three types if rocks.

Rocks y r a t n e m di e S

or tam Me

g

ck s o R s u o ne

phic Rocks

I

10

Activity 6.4

Properties of Soil Warning: Soil contains microorganisms that can be harmful if they get inside your body. Be sure to wash your hands thoroughly after completing your observations.

Materials • 3 labeled soil samples

• funnel

• paper towel

• 2 measuring cylinders

• hand lens

• tablespoon

• filter paper

• stopwatch

Make a Prediction Use the hand lens to observe each soil sample. Predict which sample is clay, sand and potting soil.

Sample A: Sample B: Sample C:

11

Procedure 1. Spread soil sample A onto the paper towel.

Use the hand lens to closely observe the soil particles. Record the properties of the soil including particle size and amount of humus.

2. Line the funnel with filter paper. Place two tablespoons of soil sample A into the funnel.

Place the funnel of soil on the top of one measuring cylinder.

3. Use the other measuring cylinder to pour 100 ml of water into the funnel.

4. Using the stopwatch, observe the volume of water that flows through the soil into the measuring cylinder.

5. Repeat Steps 1 to 4 for the other soil samples.

Observations Use the table to record your observations.

Soil Sample A

B

C

12

Properties

Water in Cylinder

Analyze and Interpret 1. Was your prediction correct? Which type of soil was in each sample?

2. Order the soils by the amount of water that passed through, from the least (1) to the most (3).

1.

2.

3.

3. Which type of soil do you think would be the best for growing plants?

Explain your answer.

4. Which type of soil would not be suitable for growing plants?

Explain your answer.

13

Activity 6.5

Observing Soil Particles at School Warning: Soil contains microorganisms that can be harmful if they get inside your body. Be sure to wash your hands thoroughly after completing your observations.

Materials • 3 beakers

• funnel

• spade

• hand lens

• stirring rod

• stopwatch

Procedure 1. Go into your schoolyard and collect soil from three different locations. Try to find locations where the properties of the soil will be different. Use the spade to put soil into each beaker so that it is about one third full.

2. In the classroom, add water to each beaker so that the water is two centimeters from the top. Use the stirring rod to thoroughly stir each beaker.

3. Start the stopwatch. After one hour, observe the soil layers and water in each beaker. Use the hand lens to observe the soil particles in each layer. Record you observations.

14

Observations Draw, label and describe the soil and water in each beaker after it settled.

Location:

Location:

15

Location:

Analyze and Interpret

1. Describe the soil particles in each layer.

2. The bottom layer of soil likely contained sand and small rocks. Why did they settle on the bottom?

16

3. At which location in the schoolyard does the soil contain the most sand?

4. At which location in the schoolyard does the soil contain the least sand?

5. Laying on the sand particles and small rocks are silt and clay particles.

Why did these settle on top of the sand and small rocks?

6. At which location in the schoolyard does the soil contain the most silt and clay?

7. At which location in the schoolyard does the soil contain the least silt and clay?

8. Floating on the water is likely humus. At which location in the schoolyard does the soil contain the most humus?

9. At which location in the schoolyard does the soil contain the least humus?

10. How do the size and type of soil particles affect the properties of soil?

17

Activity 6.6

Chemical Weathering Materials • chalk

• 2 beakers

• masking tape

• spoon

• vinegar

Procedure

1. Use the masking tape to label the beakers A and B. 2. Place two whole pieces of chalk into Beaker A. 3. Break up two pieces of chalk into small pieces. Place the pieces of chalk into Beaker B. 4. Pour vinegar into each beaker so that all of the chalk is covered.

5. Start the stopwatch and observe what happens.

6. After 5 minutes, use the spoon to raise and observe the chalk in both beakers.

7. Repeat Step 6 after 30 minutes and after 60 minutes.

18

• safety goggles

Observations In the table below, describe the chalk in each beaker.

Time (min)

Chalk in Beaker A

Chalk in Beaker B

5

30

60

Analyze and Interpret 1. What caused the changes you observed in the chalk?

2. In which beaker was the chalk broken down the most? Why?

3. How are the changes you observed similar to the chemical weathering of limestone in nature?

19

Activity 6.7

Physical Weathering Materials • 3 plastic containers with lids

• hand lens

• clay

• stopwatch

Procedure 1. Use the clay to make nine small balls of the same size. Allow the balls to harden by placing them in sunlight for a day or letting them sit overnight.

2. Use the masking tape to label the containers A, B and C. 3. Place three clay balls into each container. Fill each container with the same amount of water. Place the lid on each container.

20

• masking tape

4. Start the stopwatch and shake Container A for 30 seconds. Remove the lid, drain the water and use the hand lens to observe the clay balls.

5. Restart the stopwatch and shake Container B for two minutes. Remove the lid, drain the water and use the hand lens to observe the clay balls.

6. Remove the lid from Container C, drain the water and use the hand lens to observe the clay balls.

Observations Draw and describe the clay balls in each container.

Container A:

Container B:

21

Container C:

Analyze and Interpret

1. Explain the cause of the changes you observed.

2. What differences did you observe in the balls in Containers B and C?

3. How is what happened to the clay balls similar to weathering in nature?

22

Activity 6.8

Comprehension – Weathering 1. Use your textbook to help you fill in the blanks. (a) The process whereby a chemical reaction causes rocks to break down is called

.

(b) List two common examples of chemical weathering.

(c) Acid rain occurs when harmful the oxygen and falls back to Earth to be acidic.

combine with in the air causing the rain that

(d) A chemical reaction between the oxygen in the air or water can cause rocks to rust.

in rocks and

(e) Weathering caused by forces is called

.

(f) List three forces that can cause physical weathering.

2. Are chemical weathering and physical weathering rapid or slow processes? Explain your answer.

23

Activity 6.9

Comprehension – Erosion 1. Use your textbook to help you fill in the blanks. (a) The process by which weathered rock particles are moved to new locations is called

.

(b) List three main causes of erosion.

(c)

The slow movement of

also cause

down mountains can .

(d) On beaches, and breezes move sand from place to place. This forms large piles of sand, called

.

(e) Describe one way animals can contribute to erosion.

2. How do weathering and erosion work together to change the surface of the Earth?

24

Activity 6.10

Weathering, Erosion and Deposition Wind and water are continually changing the surface of the Earth through the processes of weathering, erosion and deposition. In this investigation, you will build a model of a natural environment to demonstrate how these processes shape the land.

Materials List the objects or materials you will need to carry out this investigation.

Procedure List the steps you will take to carry out the investigation. Describe how you will simulate the wind and moving water.

25

Draw a Model Draw your model before and after weathering, erosion and deposition took place. Label any landforms and water sources.

Before

After

26

Observations Describe how your model showed the processes of weathering, erosion and deposition.

Weathering:

Erosion:

Deposition:

Analyze and Interpret 1. Using your model, what things could you do to increase the rate of erosion and deposition?

2. Using your model, what things could you do to decrease the rate of erosion and deposition?

27

Activity 6.11

Factors Affecting Erosion – Plants Materials • 2 radish seedling trays

• beaker

• large aluminum tray

• masking tape

Make a Prediction How will the removal of radish seedlings affect the rate of erosion by water? Explain your answer.

Procedure 1. Use the masking tape to label the seedling trays A and B. 2. Place Tray A in the aluminum tray at an angle as shown.

3. Use the beaker to slowly pour 250 ml of water over the soil. Observe the water and soil that is washed into the aluminum tray.

28

4. Remove all of the radish seedlings from Tray B. 5. Repeat Steps 2 and 3 using Tray B.

Observations Describe what you observed in each aluminum tray. Which aluminum tray contained the most soil?

Analyze and Interpret 1. Was your prediction correct? What effect did removing the seedings from the soil have on the rate of erosion?

2. How would clearing the trees and other plants from a forest affect the rate of erosion when it rains?

29

Activity 6.12

Slope and Erosion As a class, plan and conduct an investigation to find out the effect of slope on the rate of erosion caused by the downhill movement of water.

Materials List the materials you will use to carry out the investigation.

Make a Prediction How do you think the rate of soil erosion will be affected when the slope angle of the soil is increased? Explain your answer.

Procedure List the steps you will take to carry out the investigation.

30

Draw a Model Draw a labeled model to show how you carried out the investigation.

31

Observations Describe what you observed during the investigation.

Analyze and Interpret 1. Was your prediction correct? Based on your observations, what can you infer about the effect of slope on the rate of soil erosion?

2. Which things did you keep the same in this investigation? Why was this important?

3. What effect would changing the amount and speed of the flowing water have on the rate of soil erosion? How could you find out?

32

Activity 6.13

Weathering and Erosion by People 1. Provide two examples of weathering that is caused by people.

2. Provide two examples of erosion that is caused by people.

3. Describe an example in your local area where people are contributing to weathering and erosion. How is the shape of the land changing?

4. Using the example you provided in question 3, suggest a way the weathering and erosion can be prevented or reduced.

33

Activity 6.14

Water, Erosion and Deposition Materials • aluminum tray

• sand

• measuring cylinder

• books

• stones

Make a Prediction How do you think the rate of soil erosion and deposition of sand and rock by water will be affected when the amount of water is increased?

Explain your answer.

Procedure 1. Mix the sand and stones together to form a sandstone-like mountain slope at one end of the aluminum tray as shown.

34

2. Place some books under one end of the tray so that the mountain sits at the higher end of the tray.

3. Fill the measuring cylinder with 25 milliliters of water and gently pour the water on top of the mountain.

Observe the effect of the water on the mountain.

4. Rebuild another mountain of the same size. Repeat Step 3 three more times, increasing the amount of water by 25 milliliters each time.

Observations Use the table to record your observations.

Amount of Water

How the Mountain Was Affected

Diagram

25 ml

50 ml

75 ml

100 ml

35

Analyze and Interpret 1. Was your prediction correct? How did increasing the amount of water affect the rate of erosion?

2. Which things did you keep the same in this investigation?

Why was this important?

3. Use the words ‘erosion’ and ‘deposition’ to describe what occurred when water was poured on the mountain.

36

Engineer It!

The Impacts of Floods Floods can impact people in a number of ways. In this activity, you will build a model of a river and the surrounding land to show how floods can impact people. Using the same model, design and build a solution to reduce the impact of a flood.

Materials • plastic container

• newspaper

• soil

• sticks and leaves

• watering can

• art and craft supplies

• jug

Procedure 1. I n the plastic container, use the newspaper and soil to make a model of a river and flat land as shown on the next page.

2. Use art and craft supplies to build models of objects such as houses, farmland, roads and vehicles.

3. Pour water into to the ‘river’ part of your model. Keep adding water until the river floods onto land.

37

4. Use the watering can to pour water over the land to simulate further flooding by rain. Observe the impacts of the flood on the land and objects.

Observations Describe the impacts the flood had on the coastline.

Analyze and Interpret In small groups, discuss and list some solutions to the problems caused by flooding.

38

The Solution 1. Describe the solution you will use to reduce the impacts of flooding.

2. Draw a model to show how your solution will work.

3. Set up the river and land model in the same way as outlined in the procedure. Add your solution and test it by simulating flooding again.

4. Evaluate the effectiveness of your design. How could it be improved?

5. Compare your solution with others in your class. What were some other solutions to the impacts of flooding?

39

Activity 6.15

Comprehension – Structure of the Earth 1. Use your textbook to help you fill in the blanks. (a) The Earth is made up of three layers – the

,

and

.

(b) The inner-most part of the Earth is called the It is also the

.

part.

(c) The center of the core is the inner core. It is made of

. Surrounding the inner core is the outer core.

The outer core is made of (d) The

. lies between the core and the crust.

(e) The is the thinnest, outer-most part of the Earth and the part we live on. The crust is made up of

and

.

(f) The outer part of the Earth is divided into large, slow-moving pieces of solid rock called

.

2. List four events that can occur when tectonic plates interact at boundaries.

40

Engineer It!

Withstanding an Earthquake!

A common impact of large earthquakes in cities is the collapse of buildings due to the force of the Earth’s shaking crust. Along with destroying buildings, the collapses can cause serious injury and death. Replacing and repairing buildings also costs a lot of money.

To reduce the impact of earthquakes in cities, engineers design and construct buildings that are able to withstand the violent shaking caused by earthquakes.

They do this by using materials that are strong, flexible or that can absorb the vibrations caused by the earthquake.

Now it’s your turn. In small groups, design and build a tall building that can withstand an earthquake. Your building must be between 30 and 40 centimeters tall. Test the effectiveness of each group’s design by seeing which building can withstand the most shaking.

41

Materials List the materials you will use to construct the building.

Draw a Model Draw a labeled diagram of your design.

42

Procedure As a class, decide on a way to test the effectiveness of each group’s design. Write the steps you will take.

Analyze and Interpret 1. What properties of the materials you used make them suitable for their purpose?

2. Describe how your building will withstand the shaking of an earthquake.

3. Evaluate the effectiveness of your group’s design. How did it compare with the designs made by other groups?

4. How could your group’s design be improved?

43

Activity 6.16

How Tsunamis Can Change the Coastline Materials • large aluminum tray

• sticks and leaves

• newspaper

• art and craft supplies

Procedure 1. In the aluminum tray, use the newspaper and soil to create a flat coastal area of land that slopes to the bottom of the tray as shown.

2. Use the art and craft supplies to construct model houses and shops. Place them on the flat part of the land you created.

3. Pour water into the uncovered part of the tray to represent water in the ocean.

4. Place the corrugated plastic vertically in the water and move it gently back and forth.

Observe how the waves affect the land.

5. Use stronger back and forth movements to create large tsunami-like waves. Observe how the waves affect the land.

44

• soil

• corrugated plastic

Draw a Model Draw labeled diagrams to show the model before and after the ‘tsunami’.

Before

After

45

Observations Describe the impact the tsunami had on the coastline.

Analyze and Interpret 1. Describe the ways in which a tsunami can change a coastal area.

2. Describe the impacts a tsunami can have on the people living in the coastal area.

3. What can people do to reduce the impact of a tsunami?

46

Activity 6.17

Rapid Changes to the Earth’s Surface 1. Describe each hazard and its effect on the Earth’s surface. List some ways the hazard affects people.

(a) Natural Hazard:

Effect on Earth’s surface:

Effects on people:

(b) Natural Hazard:

Effect on Earth’s surface:

Effects on people:

47

(c) Natural Hazard:

Effect on Earth’s surface:

Effects on people:

(d) Natural Hazard:

Effect on Earth’s surface:

Effects on people:

48

(e) Natural Hazard:

Effect on Earth’s surface:

Effects on people:

(f) Natural Hazard:

Effect on Earth’s surface:

Effects on people:

49

2. Use a Venn diagram to compare and contrast the causes and impacts of earthquakes and volcanic eruptions.

Earthquakes

Volcanic Eruptions

3. Use a Venn diagram to compare and contrast the causes and impacts of hurricanes and tsunamis.

Hurricanes

Tsunamis

4. How are the causes of earthquakes, volcanoes and tsunamis related?

50

Activity 6.18

Learning From Fossils Materials • assorted fossils

• hand lens

Procedure 1. Your teacher will set up fossil observation stations in the classroom.

2. Move from station to station and examine each fossil. Use the hand lens to observe each fossil closely.

Observations Record your observation in the space below.

Fossil A:

Type of organism:

Where it lived:

land

water

Similar organisms alive today:

51

Fossil B:

Type of organism:

Where it lived:

land

water

Similar organisms alive today:

Fossil C:

Type of organism:

Where it lived:

land

water

Similar organisms alive today:

Fossil D:

Type of organism:

Where it lived:

land

Similar organisms alive today:

52

water

Analyze and Interpret 1. What characteristics of each fossil helped you determine the type of organism?

2. How were you able to determine where the organism lived?

3. Observe the fossils below.

Fossil W

Fossil X

Fossil Y

Fossil Z

(a) What can you infer about the environment where the organism in Fossil X lived?

(b) Scientists discovered Fossil W and Fossil Z in the same layer of sedimentary rock. What can you infer about the organisms that made these fossils?

(c) Scientists discovered Fossil Z several rock layers below Fossil Y. What can you infer about the organisms that made these fossils?

53

Activity 6.19

Earth Long Ago Use the diagram below to answer the questions on the next page.

54

1. What can you infer about the organism that formed each fossil? (a)

(b)

(c)

2. What likely formed the canyon in the picture? How do you know?

3. What can you infer about all of the fossils in the uppermost layer of rock?

How do you know?

4. Scientists have discovered fossilized seashells in the center of the United States, thousands of kilometers from the ocean. What can they infer about the area in the past? Explain your answer.

55

Review

Processes That Shape the Earth 1. Why are minerals important to plants and animals?

2. How do plants and animals get the minerals they need?

3. Why is it useful to know about the properties of minerals?

4. How is sand different from humus?

5. Use the Venn diagram to compare and contrast chemical and physical weathering.

Chemical Weathering

56

Physical Weathering

6. Describe the process of frost wedging.

7. List three forces in nature that cause erosion.

8. How does removing vegetation from an area affect the rate of erosion?

9. Use the diagram to list six ways in which the surface of the Earth can be changed rapidly.

Rapid Changes

57

10. Describe how living things affect the physical characteristics of their environments.

11. List the three layers of the Earth.

12. List three natural hazards that can occur due to interactions at the boundaries of tectonic plates.

13. Provide an example of how we can reduce the impacts of floods.

14. Scientists discover fossils in three different rock layers in the same location. What can they infer about the fossils in the bottom layer of rock? Explain your answer.

58

Activity 7.1

Earth’s Landforms Chelsea and her class went on a field trip to a national park near her school.

On the field trip, she made some great sketches of the diverse landforms and water sources scattered throughout the park. Help Chelsea name and briefly describe the features she sketched.

Name of feature: Description:

Name of feature: Description:

59

Name of feature: Description:

Name of feature: Description:

60

Name of feature: Description:

Name of feature: Description:

61

Activity 7.2

Comprehension – Earth’s Landforms 1. Use your textbook to help you fill in the blanks. (a) A

is a landform that rises above the

surrounding land. It has steep and a sharp or rounded peak. They are formed by the pushing together of the Earth’s

or volcanic eruptions. They often form

in groups called (b)

. are wide, flat landscapes with little elevation.

Many are formed over time by the

of the

land from nearby hills or mountains. Other plains were formed by

of sediment by water or wind.

(c) A is low-lying area between mountains.

Often, water flows through a valley as .

Some are formed by the Others are formed by running water such as a

62

of glaciers. .

(d) A

is a deep, narrow channel that

runs through

. They are created by of uplifted sedimentary rock usually caused

by a (e) A

running through it. is flat terrain that elevates sharply from

the surrounding land on at least one edge. A forms as the result of the upward movement of the

flow of

.A

is formed by the as the result of volcanic eruptions.

2. In what ways are valleys and canyons similar? How are they different?

3. In what ways are plains and plateaus similar? How are they different?

4. List three processes that shape the Earth’s landforms.

63

Activity 7.3

Local Land and Water Features 1. As a class, visit a local natural area. Observe the features of the land and water. Draw a labeled diagram of four features. Provide the location and a description of each feature. Tell how each feature may have formed.

Type of feature:

Location: Description:

How it may have formed:

Type of feature:

Location: Description:

How it may have formed:

64

Type of feature:

Location: Description:

How it may have formed:

Type of feature:

Location: Description:

How it may have formed:

2. Do you think the area you visited will have the same features millions of years from now? Explain your answer.

65

Activity 7.4

Modeling the Earth’s Features If you have ever visited a museum, you may have seen a diorama. A diorama is a three-dimensional model of an area. They are a great way to show the Earth’s features and are fun to make too! In this activity, you are going to make a diorama of your favorite place in nature. Be sure to include and label the different features of the area.

Suggested Materials • shoebox

• newspaper

• art and craft supplies

• scissors

• sticks, stones and leaves

• paint

• glue

1. Name and give the location of your favorite place in nature that you will be modeling in your diorama.

2. Describe the area, its landforms and water sources.

66

Draw a Model 1. Use the materials to create your diorama. Paste a photograph or draw a labeled diagram of your diorama.

2. Present your diorama to your classmates. See if they are able to identify its features and name the place or location.

3. After seeing the dioramas made by your classmates, can you suggest some ways your diorama could be improved?

67

Activity 7.5

The Ocean 1. Why does the Earth look blue when viewed from space?

2. How much of the Earth’s surface is covered by the ocean?

3. Where does the salt in the ocean’s salt water come from?

68

4. In what ways are features of the ocean floor similar to Earth’s landforms?

5. How does the depth of the ocean change as you move away from the coast?

6. Use the words in the box to label the diagram.

Try to do this without looking in your textbook. continent continental shelf trench mid-ocean ridge

abyssal plain sea mount island continental slope

69

Activity 7.6

Earth’s Fresh Water 1. What percent of the water on Earth is fresh water?

2. Why is most of the fresh water on Earth unavailable for use by people?

3. What percent of the fresh water on Earth is available for people to use?

4. What is groundwater and how can it be used by people?

5. List four places where usable fresh water can be found on Earth.

6. Why is it important to keep our freshwater resources clean?

70

7. Look at the water cycle diagram below. Explain what occurs at each stage. Draw arrows to show how water moves.

1

2

3

4

3 2

1

4

71

Activity 7.7

Using Maps Look at each map. Describe what the map shows and who may find the map useful.

1.

What the map shows:

Who would find this map useful:

72

2.

What the map shows:

Who would find this map useful:

73

3.

What the map shows:

Who would find this map useful:

74

4.

What the map shows:

Who would find this map useful:

75

5.

What the map shows:

Who would find this map useful:

76

Activity 7.8

Map Features Label the features of a map and explain its purpose.

Feature:

Feature:

Purpose:

Purpose:

Lake Boulder National Park – Hiking and Camping Map Key campfire toilet campsite bridge lookout Arrow Ridge Trail Big Moose Trail Brown Bear Trail

Feature:

Feature:

Purpose:

Purpose:

77

Activity 7.9

Map Patterns in the United States In small groups, observe the map below. Discuss the things the map shows and any patterns you can see.

78

1. What does the map show?

2. What water sources can you see on the map?

3. What landforms can you see on the map?

4. Describe any patterns in the location of landforms you see on the map.

5. Circle an area on the map that is likely to have volcanic activity.

Explain why you circled that part of the map.

79

Activity 7.10

Comprehension – Ocean Patterns 1. Use your textbook to help you fill in the blanks. (a) Many of the processes that shape the Earth’s land also shape the

.

(b)

are narrow and very long sunken areas

on the ocean floor. They have the (c)

sides and form

parts of the ocean.

Like mountains and volcanoes, ocean trenches commonly occur at

.

(d) An

is a wide,

area on the deep ocean floor. They are usually found at depths over

.

(e) Like mountains on land, an

is a sudden rising

of the ocean floor caused by the movement of the Earth’s plates.

2. What is the mid-ocean ridge?

80

Activity 7.11

Observing Ocean Patterns Your teacher will display a digital map of the ocean floor. As a class, identify some ocean floor features. Discuss some patterns you see on the map.

1. List some of the ocean floor features you can see on the map. Draw and label them on the map on the next two pages.

2. Describe any patterns you can see.

3. Identify the Ring of Fire and draw it on the map on the next page.

4. What is the Ring of Fire?

5. Why are earthquakes and volcanic eruptions common in the Ring of Fire?

81

82

83

Review

Mapping the Earth’s Surface 1. Complete the table.

Landform

Characteristics

Mountain Plain Valley Canyon Plateau 2. Use the Venn diagram to compare and contrast the ocean and a lake.

Ocean

Lake

3. How does the depth of the ocean change with distance from a continent?

84

4. Where can fresh water be found on Earth?

5. What percent of the fresh water on Earth is available for people to use?

6. Why is the scale a useful map feature?

7. Why do earthquakes and volcanoes often occur in the same area?

8. Complete the table.

Ocean Floor Feature

Characteristics

Ocean Trench Abyssal Plain Ocean Ridge

85

Activity 8.1

What Are Natural Resources?

1. What are natural resources?

2. What is the difference between renewable and non-renewable resources?

3. Name each natural resource. Describe where it comes from and how it is used by people. Circle to indicate whether it is a non-renewable or renewable resource.

Natural Resource:

Where it comes from:

How it is used:

Renewable Non-renewable

86

Natural Resource:

Where it comes from:

How it is used:

Renewable Non-renewable

Natural Resource:

Where it comes from:

How it is used:

Renewable Non-renewable

87

Natural Resource:

Where it comes from:

How it is used:

Renewable Non-renewable

Natural Resource:

Where it comes from:

How it is used:

Renewable Non-renewable

88

Natural Resource:

Where it comes from:

How it is used:

Renewable Non-renewable

Natural Resource:

Where it comes from:

How it is used:

Renewable Non-renewable

89

Activity 8.2

Fossil Fuels 1. Use your textbook to help you answer the questions and fill in the blanks. (a) What are fossil fuels?

(b) List three fuels produced from fossil fuels.

(c)

Fossil fuels take

They are called used up much faster than they can be 2. Describe how fossil fuels are formed.

3. Why should we conserve fossil fuels?

90

of years to form. resources because they are .

Activity 8.3

Comprehension – Fossil Fuels and Electricity 1. Use your textbook to help you answer the questions and fill in the blanks. (a) Coal, natural gas and petroleum are commonly used to produce

.

(b) The fuels are burned to transform the in the fuel into

energy which is used to convert

water into (c)

.

The steam generated spin

a energy into

energy

which then turn

which converts the energy.

2. How can producing electricity by burning fossil fuels harm the environment?

91

Activity 8.4

Renewable Energy 1. List the renewable energy source and describe how electricity is produced.

(a) Solar Electricity

Renewable energy source:

How electricity is generated:

(b) Wind Turbine

Renewable energy source:

How electricity is generated:

92

(c) Hydroelectricity

Renewable energy source:

How electricity is generated:

(d) Tidal Energy

Renewable energy source:

How electricity is generated:

2. What are the advantages of producing electricity using renewable energy sources?

93

Activity 8.5

Environmental Impacts 1. Describe the environmental impacts of using the Earth’s resources.

94

(a) Mining Coal:

Environmental Impact:

(b) Drilling for Petroleum:

Environmental Impact:

(c) Burning Fossil Fuels:

Environmental Impact:

2. What is acid rain? How is it produced?

3. Why is it important to conserve the Earth’s non-renewable natural resources?

95

Activity 8.6

Solutions to Environmental Impacts Read the problem caused by using the Earth’s natural resources.

Provide a solution to the problem.

1.

Problem The construction of a dam will result in the loss of habitat of many organisms. Changes to the natural water flow will also impact organisms downstream of the dam.

Solution

96

2.

Problem Emissions from a coal-fired power plant is causing poor air quality in a nearby city. Strong winds are causing acid rain to fall in a nearby nature reserve.

Solution

97

3.

Problem Heavy traffic in a city is causing increased emissions from cars and other vehicles. The emissions are causing air pollution which is affecting the health of the people in the city.

Solution

98

4.

Problem A town closed down a coal-fired power plant and now relies only on wind farms to generate electricity. During summer, the electricity supply is insufficient to run air conditioners in buildings and homes.

Solution

99

Activity 8.7

Local Environmental Impacts 1. As a class, discuss some of the ways in which the use of the Earth’s natural resources is impacting your local environment. List the impacts you identify.

2. In small groups, choose one impact to the environment caused by using natural resources. Define the problem and provide a solution.

Problem

100

Solution

3. What other solutions were proposed by other groups?

4. Reflect on the design of your solution. How could you improve the effectiveness of your solution?

101

Review

Using Earth’s Resources 1. What is a natural resource?

2. Why are fossil fuels non-renewable resources?

3. List two ways people use fossil fuels.

4. List three renewable resources.

5. Use the words in the box to fill in the blanks. generator electricity fossil fuel steam Coal is a type of

. In a coal-fired power plant, coal

is burned to turn water into which then turn a

. This spins turbines . The

produced is sent to homes, buildings and cities.

102

6. Provide two reasons why producing solar electricity is less harmful to the environment than electricity produced by burning fossil fuels.

7. How does the release of harmful emissions into the air affect people and other organisms?

8. What effect does increased greenhouse gas levels have on the atmosphere?

9. List three effects of global climate change.

10 . How can technology help to reduce the impact of using the Earth’s natural resources?

103

Activity 9.1

What Is Energy?

1. What is energy? Give two examples.

2. Where do plants get the energy they need?

3. Give three examples of how you use energy in your daily life.

4. Where do animals and people get the energy they need?

5. Use your textbook to help you fill in the blanks. (a) Energy cannot be

or

It can be

.

from one form to another.

(b) A television is a device that uses The

104

energy.

energy is transformed into ,

and energy.

Activity 9.2

Potential and Kinetic Energy Materials • toy car

• blocks

• cardboard or corrugated plastic

• measuring tape

Procedure 1. Use the cardboard and blocks to make a ramp.

2. Place the toy car at the top of the ramp and release it.

3. Measure the distance the car travels from the bottom of the ramp.

Repeat four times and record your observations.

105

4. Use more blocks to increase the height of the ramp.

Repeat Steps 2 and 3.

Observations Draw the two ramps you constructed. Show the difference in height.

106

Record the distance the toy car traveled in each trial in the table below.

Trial

Ramp 1

Ramp 2

1 2 3 4 5

Analyze and Interpret 1. Compare the speed of the toy car when released from each ramp.

2. Which ramp resulted in the toy car traveling further?

3. Describe your results in terms of potential and kinetic energy.

4. Based on your observations, what can you infer about an object’s speed and its energy?

107

Activity 9.3

Potential and Kinetic Energy Conversion Color the bars to show how the amount of potential energy and kinetic energy of a roller coaster car changes as it moves. (a) The car is at rest at the top of the track.

Kinetic Energy

Potential Energy

Kinetic Energy

Potential Energy

Kinetic Energy

Potential Energy

(b) The car is about half way down the track.

(c)

108

The car is at the bottom of the track.

Activity 9.4

Energy and Mass As a class, plan and conduct an investigation to find out how mass effects the kinetic energy of a moving object.

Materials List the materials you will use to carry out the investigation.

Make a Prediction Will objects with greater mass have greater kinetic energy? Explain your answer.

Procedure List the steps you will take to carry out the investigation.

109

Draw a Model Draw a labeled model to show how you carried out the investigation.

1 10

Observations Describe what you observed during the investigation.

Analyze and Interpret 1. Was your prediction correct? Based on your observations, what can you infer about the effect of mass on the kinetic energy of an object?

2. Which things did you keep the same in this investigation?

Why was this important?

111

Activity 9.5

Coin Collisions Materials • roll of pennies

• smooth surface

Procedure 1. Place a penny on a smooth surface such as a table top. Take another penny and slide it towards the placed penny with a small force. Observe the sound when the two pennies collide. Observe their new positions.

2. Repeat Step 1 but apply a greater force to the sliding penny.

3. Make a stack of 5 pennies and repeat Steps 1 and 2.

4. Make a stack of 10 pennies and repeat Step 3.

1 12

Observations Draw the pennies after the collision.

Describe the sound made by the collision.

One penny small force

large force

Five pennies small force

large force

1 13

Ten pennies small force

large force

Analyze and Interpret 1. In what ways did applying a larger force to the penny affect the collisions?

2. In what ways did the larger stacks of pennies affect the collisions?

1 14

Activity 9.6

Forms of Energy 1. Complete the tables for each form of energy.

Sound Energy Brief Description

Example Source

How is it useful?

Thermal Energy Brief Description

Example Source

How is it useful?

1 15

Light Energy

Brief Description

Example Source

How is it useful?

Electrical Energy

Brief Description

Example Source

How is it useful?

1 16

Chemical Energy

Brief Description

Example Source

How is it useful?

2. Give an example of a device that outputs two or more forms of energy.

Draw and label a diagram of the device.

1 17

Engineer It!

Transforming Energy Many devices you are familiar with transform energy from one form to another. A flashlight transforms electrical energy into light and heat.

Flashlights are useful as they solve a human problem of seeing in the dark.

input energy

output energy

electrical

light and heat Device

Now it’s your turn. Identify and define a human problem that can be solved with a device that transforms energy from one form to another. Design, build and test the device.

Materials List the materials you will use to build your device.

1 18

Draw a Model 1. Draw a labeled diagram of your design.

2. Show how your device transforms energy.

input energy

output energy

Device 1 19

Procedure Write the steps you will take to build and test your device.

Analyze and Interpret 1. What properties of the materials you used make them suitable for their purpose?

2. Describe how your device solved a human problem.

3. Evaluate the effectiveness of your design in solving the human problem.

4. How could the design be improved?

12 0

Activity 9.7

Energy Conversion 1. What energy conversion takes place when you rub the palms of your hands together?

2. What energy conversion takes place when you clap your hands?

3. What energy conversion takes place when a stretched bow is released?

121

4. What energy conversion takes place in a solar panel?

5. What energy conversion takes place when a gas burner is lit?

6. What energy conversion takes place when a flashlight is switched on?

122

Activity 9.8

Comprehension – Electric Charge and Circuits 1. Use your textbook to help you fill in the blanks. (a) Charges are small particles that exist in all forms of matter. They can be

or

.

(b) An imbalance of charge in matter causes an (c)

Like charges

.

each other. Opposite charges each other.

(d) When charges build up, they can move from once place to another. This movement is called an

.

(e)

is the continuous flow of electric charge.

(f)

allow charges to flow freely.

(g) An

restrict the flow of charges. is a path around which electricity flow.

123

2. Dominic rubs a balloon on a fabric cloth and holds it to a wall. He observes that the balloon appears to stick to the wall. Describe what is happening in terms of electric charge.

3. What are electrical conductors? Provide an example.

4. What are electrical insulators? Provide an example.

5. Draw and label a diagram that shows a closed electric circuit with a battery, switch, a bulb and wires.

12 4

Activity 9.9

Building Electric Circuits Materials • dry cell in holder

• wires

• light bulb in holder

• crocodile clips

• buzzer

• switch

• fan

Procedure 1. Assemble the circuit components as shown.

2. Use the crocodile clips to connect the buzzer to the circuit.

Close the switch and observe what happens.

3. Use the circuit symbols on the next page to draw a circuit diagram.

Add arrows to show how electricity flowed through the circuit.

4. Repeat Steps 2 and 3 using the light bulb.

5. Repeat Steps 2 and 3 using the fan.

125

Draw a Model Use the circuit symbols below to draw a circuit diagram for each circuit you built.

wire

dry cell Circuit with light bulb:

Circuit with buzzer:

126

open switch

light bulb

closed switch

motor

buzzer

Circuit with fan:

Analyze and Interpret 1. What energy conversion occurred when you closed the switch in the circuit with the light bulb?

2. What energy conversion occurred when you closed the switch in the circuit with the buzzer?

3. What energy conversion occurred when you closed the switch in the circuit with the fan?

127

Activity 9.10

Energy Transfer As a class, plan and conduct an investigation that shows how energy can be transferred from place to place. You may wish to show how collisions transfer kinetic energy or how light, heat and sound move from place to place.

Materials List the materials you will use to carry out the investigation.

Make a Prediction Describe how you think energy will be transferred from place to place in this investigation.

Procedure List the steps you will take to carry out the investigation.

128

Draw a Model Draw a labeled model to show how you carried out the investigation.

129

Observations Describe what you observed during the investigation.

Analyze and Interpret 1. Was your prediction correct? Describe how energy was transferred during the investigation.

2. Describe how energy moves from place to place when the switch is turned to the ‘on’ position.

130

Review

Energy and Motion 1. What is energy?

2. Provide an example where potential energy is converted into kinetic energy.

3. How is the speed of an object related to its energy?

4. What affects the impact of a collision?

5. True or false. (a) Sound and light are examples of potential energy. (b) Sound can travel through solids, liquids and gases.

6. How is the movement of particles within an object related to its thermal energy?

131

7. Complete the table.

Form of Energy

Brief Description

Example

Sound Thermal Light Electrical Chemical 8. What energy conversion takes place when a flashlight is switched on?

9. What is the difference between electric charge and electric current?

10. Complete the table.

Circuit Component Battery Switch Wires 132

Function

Activity 10.1

Creating and Observing Waves Materials • large tub of water

• plastic bottle

• cork

Procedure 1. Make sure the water in the tub is calm and still. Place the cork in the middle of the tub.

2. Place the plastic bottle on the surface of the water at one end of the tub. Gently move the bottle up and down to create waves.

3. Observe the motion of the cork and record your observations.

4. Create larger waves by using a greater force to move the bottle up and down. Observe the motion of the cork and record your observations.

133

Observations Draw two diagrams to show how the cork moved. Show how it moved from its starting position and how its height changed with the motion of the waves.

Small waves:

Large waves:

13 4

Analyze and Interpret 1. Describe the motion of the waves in the tub.

2. Describe the motion of the cork when small waves were produced.

3. Describe the motion of the cork when large waves were produced.

135

Activity 10.2

Characteristics of Waves 1. Draw a wave that has a greater amplitude.

2. Draw a wave that has a shorter wavelength.

3. Draw a wave that has a longer wavelength and smaller amplitude.

13 6

2. Halle hits some keys on a xylophone. Match the wave that best describes the sound produced.

Shortest key hit very softly.

Shortest key hit very hard.

Middle key hit very hard.

Longest key hit very hard.

Longest key hit very softly

137

Activity 10.3

Reflecting Sound Waves As a class, plan and conduct an investigation to find out if sound waves can be reflected.

Materials List the materials you will use to carry out the investigation.

Make a Prediction Can sound waves be reflected? Explain your answer.

Procedure List the steps you will take to carry out the investigation.

13 8

Draw a Model Draw a labeled model to show how you carried out the investigation.

139

Observations Describe what you observed during the investigation.

Analyze and Interpret 1. Was your prediction correct? Based on your observations, what can you infer about the properties of sound waves?

2. Which things did you keep the same in this investigation?

Why was this important?

14 0

Activity 10.4

Creating and Observing Waves Materials • 2 mirrors

• electrical tape

• marble

Procedure 1. Place the mirrors side by side and faced down. Use a strip of electrical tape to join the mirrors together.

2. Turn the mirrors over. Place the marble on the face of one mirror. Turn the other mirror so that it forms an angle of about 120º. Observe the marble and its refection in the mirrors. Record your observations.

3. Adjust the mirrors so that they form an angle of 90º. Record your observations.

120o

90o

4. Repeat for angles of 45º and 20º.

45o

20o

141

Observations Draw a diagram to show what you observed for each angle.

How many marbles could you see?

120o

I could see

90o

marbles.

45o

I could see 14 2

I could see

marbles.

20o

marbles.

I could see

marbles.

Analyze and Interpret 1. Describe what you observed as the angle between the mirrors decreased.

2. Explain why the number of marbles observed increased as the mirrors were brought closer together.

3. Provide two examples of how mirrors and their ability to reflect light help us in our daily lives.

14 3

Activity 10.5

Refracting Light Materials • drinking glass

• sheet of white paper

Procedure 1. Draw an arrow on the paper with the marker pointing to the right.

2. Fill the glass with water and place it in front of the paper with the arrow.

3. Observe the arrow through the glass of water while you move the glass further and closer to the arrow.

4. Record your observations.

14 4

• marker

Observations 1. Draw a diagram of the arrow when observed directly and through the glass of water.

Directly:

Through water:

2. Draw lines to show what happens to the rays of light as they pass through the glass of water.

Analyze and Interpret What can you infer about light waves from this activity?

14 5

Engineer It!

Absorbing Sound When sound waves hit an object, they can be absorbed or reflected.

Different materials reflect and absorb sounds differently. As a class, design and build changes to a shoebox so that it absorbs as much sound as possible. You will test the effectiveness of your box by placing an alarm clock inside and observing how much of the sound is absorbed.

Materials List the materials you will use to build your sound-absorbing box.

14 6

Draw a Model Draw a labeled diagram of your design.

14 7

Procedure Write the steps you will take to build and test your design.

Analyze and Interpret 1. What properties of the materials you used make them suitable for their purpose?

2. Evaluate the effectiveness of your design in absorbing sound.

3. How could the design be improved?

4. How can absorbing sound waves be used to solve human problems?

14 8

Activity 10.6

Types of Waves Materials • slinky

• masking tape

Procedure 1. Attach a piece of masking tape at the center of the slinky.

2. With your partner, take an end each of the slinky and move about two meters apart so that the slinky is stretched out.

3. Take about 20 cm of the slinky and compress it together with your free hand.

14 9

4. Quickly release the compressed part of the slinky and record your observations. Observe the motion of the piece of masking tape at the center of the slinky.

5. Remain standing two meters apart and wait for the slinky to come to rest. Quickly move your hand that is holding the slinky up and down once. Observe and record the motion of the slinky and the piece of masking tape.

6. Try and create other waves and motions with the slinky.

150

Observations Draw and label a diagram to show the waves you observed in Step 4.

Describe the motion of the piece of masking tape.

Draw and label a diagram to show the waves you observed in Step 5.

Describe the motion of the piece of masking tape.

151

Analyze and Interpret 1. Waves in which matter moves perpendicular to the direction of motion are called transverse waves. Which of the waves you produced could best be described as transverse? Explain your answer.

2. Waves in which matter moves parallel to the direction of motion are called longitudinal waves. Which of the waves you produced could best be described as longitudinal? Explain your answer.

3. Give an example of transverse and longitudinal waves that you can find in nature.

152

Activity 10.7

Comprehension – Light Waves 1. Use your textbook to help you fill in the blanks. (a) Light waves are caused by the vibration of and

fields. These fields are perpendicular

to the direction of motion of the light wave. Light waves are

(b)

waves. light is a mixture of different colors

of light. The color of an object is determined by the color of light it

and reflects.

2. Label the parts of the human eye.

153

3. Describe how light moves through the eye and allows us to see.

Include the labels from question 2 in your description.

4. Name and give two examples of light we cannot see because it has a very short wavelength.

5. Name and give two examples of light we cannot see because it has a very long wavelength.

154

Activity 10.8

Sending and Receiving Digital Messages Computers process information in digital form. This is usually represented with ones and zeros. The tables below shows how letters of the alphabet can be coded in such a way.

a

0

0

0

0

1

n

0

1

1

1

0

b

0

0

0

1

0

o

0

1

1

1

1

c

0

0

0

1

1

p

1

0

0

0

0

d

0

0

1

0

0

q

1

0

0

0

1

e

0

0

1

0

1

r

1

0

0

1

0

f

0

0

1

1

0

s

1

0

0

1

1

g

0

0

1

1

1

t

1

0

1

0

0

h

0

1

0

0

0

u

1

0

1

0

1

i

0

1

0

0

1

v

1

0

1

1

0

j

0

1

0

1

0

w

1

0

1

1

1

k

0

1

0

1

1

x

1

1

0

0

0

l

0

1

1

0

0

y

1

1

0

0

1

m

0

1

1

0

1

z

1

1

0

1

0 155

1. Think of a short, secret message for your classmates to decode. Write the letters and words of your message using the 1s and 0s from the table.

My Coded Message

2. Exchange your coded message with a classmate.

See if you can decode their message.

My Decoded Message

156

Review

Waves and Information 1. In terms of energy, what are waves?

2. Describe how sound energy moves when a drum is struck.

3. How is the sound wave produced by a loud sound different from that of a soft sound?

4. How is the sound wave produced by a low-pitched sound different from that of a high-pitched sound?

5. Provide two everyday examples where light or sound waves are reflected.

6. True or false. (a) Light moves in transverse waves. (b) Sound moves in transverse waves.

157

7. Complete table.

Material

Brief Description

Example

Transparent Translucent Opaque 8. Use the words ‘reflect’ and ‘absorb’ to explain why we see the lemons as yellow and the leaves as green.

9. Use the Venn diagram to compare and contrast analog and digital signals.

Analog Signal

158

Digital Signal