Grade 4 TCI’s Grade 4 program includes four units. Each unit has a Science Journal, complete with hands-on investigations, text with notes, and checks for understanding.
Unit 4
Unit 1 Plant and Animal Structures 1 What Plant Structures Are Used for Support and Growth?
6 What Animal Structures Are Used for Support, Movement, and Protection?
2 What Plant Structures Are Used for Protection?
7 What Animal Structures Are Used for Reproduction?
3 What Plant Structures Are Used for Reproduction?
8 What Animal Structures Are Used for Sensing the
4 How Do Plants Respond to Their Environment? 5 What Animal Structures Are Used for Digestion and Circulation?
Grade 4
Waves and Information Science Journal
Environment? 9 How Do Animals Respond to Their Environment? Performance Assessment: Designing a Legendary Creature
Unit 2 Energy 1 How Are Energy and Motion Related? 2 How Is Energy Transferred by Colliding Objects?
Performance Assessment: Creating a Safety Pamphlet
3 How Is Energy Transferred by Sound, Light, and Heat?
5 How Is Energy Stored and Used?
4 How Is Energy Transferred by Electric Currents?
6 How Do People Choose Energy Resources?
Performance Assessment: Designing a Safety Device
Unit 3 Earth’s Changing Surface 1 What Are Some Clues That Earth’s Surface Changes? 2 How Does Water Change Earth’s Surface? 3 How Does Wind Change Earth’s Surface?
Performance Assessment: Investigating Changes to the Appalachian Mountains 6 Where on Earth Are Earthquakes, Volcanoes, and Mountains Found?
4 How Do Living Things Change Earth’s Surface?
7 What Can People Do About Natural Hazards?
5 How Do Fossils Form and What Do They Show?
Performance Assessment: Developing Hazard Plans
Unit 4 Waves and Information 1 What Are Some Examples of Waves?
5 How Can Sound Waves Be Used to Send Messages?
2 What Are Some Properties of Waves?
6 How Can Patterns Be Used to Send Messages?
3 How Do Waves Affect Objects?
Performance Assessment: Developing a
4 Which Waves Travel Through Earth?
Communication Method Using Waves
Engineering
Name:
Grade 4 Bring Science Alive!
Unit 4
Waves and Information Find out about waves and different ways information can be transferred to create a new communication method.
1 What Are Some Examples of Waves?........................................6 2 What Are Some Properties of Waves?.....................................28 3 How Do Waves Affect Objects?...............................................50 4 Which Waves Travel Through Earth?.........................................70 5 How Can Sound Waves Be Used to Send Messages?.............92 6 How Can Patterns Be Used to Send Messages?
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Performance Assessment: Developing a Communication Method Using Waves............................................................. 130 Engineering
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Anchoring Phenomenon Think about this unit’s Anchoring Phenomenon: People can communicate using sound waves. Complete the chart. • List what you know about this unit’s phenomenon. • Write questions you wonder about this phenomenon. Know
Wonder
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Unit Checkpoints As you complete each lesson, look for this icon learned in the lesson. Lesson
and return to record what you’ve
What I Learned
1 What Are Some Examples of Waves?
2 What Are Some Properties of Waves?
3 How Do Waves Affect Objects?
4 Which Waves Travel Through Earth?
5 How Can Sound Waves Be Used to Send Messages?
6 How Can Patterns Be Used to Send Messages?
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Unit 4 Waves and Information
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Using what you’ve learned, explain the unit’s Anchoring Phenomenon: People can communicate using sound waves.
Claim
Evidence
Reasoning
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Unit 4 Waves and Information
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Lesson 2
What Are Some Properties of Waves?
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Lesson 2 What Are Some Properties of Waves?
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INVESTIGATION
Observing Phenomena Discuss: Have you ever been to the ocean? Did you see people surfing on the waves?
Observe this phenomenon: Water waves can be big and fast enough to surf on.
Try It!
Fill a plastic container with water. What sort of water waves can you make?
Think of what you already know about the different types of waves and their properties. Write questions you have.
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Creating and Describing Waves Follow these steps to make waves on a string: • Have one group member make a wave with the string by shaking it side to side. • Have another group member make a wave that looks different from the first one. As a group, describe two ways the second wave was different from the first wave. • Draw and describe both waves. • Repeat this process until each group member has made a wave. Draw and describe each wave.
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Write each group member’s name next to the wave they make. Then, draw a diagram of the wave they make with the string. Describe two ways each wave is different from the last one.
Name
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Picture of Wave
First Difference
Second Difference
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Modeling Waves Modeling Water Waves Let’s make some other types of waves! In your container, carefully create water waves that have the following properties: • Small amplitude • Large amplitude • Short wavelength • Long wavelength
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Draw a diagram of each of the four water waves you make in your container. Small Amplitude
Large Amplitude
Short Wavelength
Long Wavelength
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INVESTIGATION
Modeling Sound Waves Now we’re going to use a spring toy to model how sound waves work. Sound waves are a little different from waves on a string and water waves. • Stretch the spring toy across a table, with one person holding it at either end. • One person holds his or her end still. Freeze! • The other person pushes his or her end forward and backward, toward his or her partner. Keep the spring toy in a straight line. Like in other waves, the wavelength in sound waves is the distance between the crests. Unlike other waves, the amplitude in sound waves refers to how much matter is pushed together and spread apart. Use your spring toy to model these sound waves: • Small amplitude • Large amplitude • Short wavelength • Long wavelength
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INVESTIGATION
Draw a diagram of each of the four sound waves you make with your spring toy. Small Amplitude
Large Amplitude
Short Wavelength
Long Wavelength
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INVESTIGATION
Complete the following statements to explain your model of what waves are and how you can describe them. We modeled three examples of waves: 1)
2)
3)
The shape and size of all of these waves are described by two properties: _______________________________ and ____________________________ Describe the two properties: ____________________ is the _________________ the crests and troughs. ____________________ is the _________________ the crests and troughs. 36
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Vocabulary Match the term to its definition. Word Bank dependent
independent
wavelength
amplitude
frequency
1. How large a wave is. The largest distance that matter in a wave moves from its rest position. 2. Two things that affect each other. 3. Two things that do not affect each other. 4. How long a wave is. The distance between a crest and the next crest in a wave. 5. How often a wave passes a certain point. The number of waves that are made in a certain amount of time
My Science Concepts Reflect on your understanding. Draw an X along each line. The amplitude of a wave tells how large it is. The wavelength tells how long it is. The frequency tells how often a wave passes a certain point. still learning
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Models help show how waves work. Models are especially helpful to analyze things that cannot be seen or that move very quickly. Diagrams and physical replicas (real objects) show how matter moves in different types of waves. In each model, you were able to change the amplitude and wavelength to see how these properties affect waves. still learning
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1. The Properties of Water Waves Think about being in a swimming pool on a warm summer day. The water is cold, so you step into it slowly. Your friend has a different idea. He jumps into the pool. SPLASH! The waves that you make are small. But the waves that your friend makes are much larger. The Amplitude of Water Waves
The water waves that you and your friend made are both water waves, but different. One of the ways you can tell these waves apart is by their amplitude. A wave’s amplitude describes how big the wave is. Amplitude is the largest distance that matter moves from its rest position. In water waves, the rest position is midway between the crest of the wave and the trough of the wave. The amplitude of a water wave is the Amplitude is the largest distance that distance from its rest position to its crest. The matter in a wave moves from its rest distance from the rest position to the trough position. A wave’s amplitude describes is also the amplitude of the wave. Matter its height. returns to its rest position after a wave has passed through it. Amplitude of a Water Wave When you and your friend jumped into the pool, the waves you caused had different patterns. When you stepped in, the waves had a small amplitude. When your friend jumped in, the waves had a large amplitude. 38
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The Wavelength of Water Waves
Wavelength of a Water Wave
The crests and troughs of a water wave can also be used to measure another property called wavelength. Wavelength is how stretched out a wave looks. It is the distance between one crest and the next crest in a wave. The distance between a trough and the next trough in a wave is also wavelength. These distances are the same. If the crests of a water wave are close together, the wave has a short wavelength. If the crests are far apart, the wave has a long wavelength. Water waves can have very different wavelengths. The wavelength of a wave in a pool might be one meter long. In a sink, the wavelength might only be a few centimeters long. The crests are farther apart in the wave in the pool than the wave in a sink. The water wave in the pool has a longer wavelength and the water wave in the sink has a shorter wavelength.
Wavelength describes how long a wave is. If a wave’s crests or troughs are close together, the wave has a short wavelength. If they are far apart, the wave has a long wavelength.
The Frequency of Water Waves Water waves have a third property called frequency. Frequency is how often a crest passes a certain point in a certain amount of time. The frequency of a wave depends on its wavelength and on how fast the wave moves. You can count crests to measure the frequency. For example, you could count how many crests pass you in one minute while you stand in the shallow part of a pool. If 12 crests pass you, then the frequency would be 12 crests per minute.
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Label the diagram below. Use the vocabulary you have learned.
How can you calculate the frequency of a water wave?
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2. The Properties of Waves on a String As you have learned, waves on a string are repeating patterns of crests and troughs, just like water waves. So, the properties of waves on a string are very similar to the properties of water waves. Amplitude of Waves on a String
Just like a water wave, the amplitude of a wave on a string describes the size of the wave. Picture a jump rope lying on the ground in a straight line. It is at its rest position. You can draw a line with chalk along the rope to see where the rest position is. Then you take one end of the rope and shake it side to side, creating a wave. The amplitude of the wave is the distance from the wave’s rest position to its crest. The amplitude is also the distance from its rest position to its trough because these two distances are the same. You can shake the rope using your whole arm by swinging your arm side to side as far as you can. You reach as far as you can to To measure the amplitude of a wave the left, then as far as you can to the right. on a string, measure the distance from You make very big waves that have a large one crest or trough to the wave’s rest amplitude. position. This distance is the wave’s amplitude. You can also shake the rope using just your wrist. You keep your whole arm Amplitude of a Wave on a String still and shake only your hand side to side. You make very small waves. These waves have a small amplitude. © Teachers’ Curriculum Institute
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Wavelength of Waves on a String
In a water wave, the wavelength is the distance between the crests of the wave. In a wave on a string, the wavelength is also the distance between the crests of the wave. The distance between the troughs of the wave is also the wavelength. You can make waves of different wavelengths in a jump rope. You can shake your hand very quickly side to side. The crests and troughs are close together, so the wave has a short wavelength. You can shake your hand side to side very slowly. The crests and troughs are far apart, so the wave has a long wavelength. For all waves, wavelength and amplitude are independent of each other. Two things are independent if they do not affect each other. So, a wave with a large amplitude can have a short or a long wavelength. A wave with a small amplitude can also have a short or long wavelength. Frequency of Waves on a String
The distance between a wave’s crests or troughs is the wavelength. These distances are the same.
Waves on a string also have frequency. Think about shaking a jump rope. You could draw a mark on Wavelength of a Wave on a String the sidewalk that is next to the middle of the jump rope. Then you could shake the rope and count how many crests pass the mark in a minute. That number per minute is the frequency of the wave. 42
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Complete the prompts in order from left to right. Wave 1
Draw a wave that has two crests and two troughs.
Wave 2
Wave 3
Wave 4
Draw what happens to Draw what happens to Draw what happens Wave 1 if you increase Wave 1 if you increase to Wave 1 if you only its amplitude. only its wavelength. increase its amplitude and decrease its wavelength.
Are wavelength and amplitude independent of each other? Why or why not?
Are wavelength and frequency independent of each other? Why or why not?
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3. The Properties of Sound Waves You have learned that water waves and waves on a string both have amplitude, wavelength, and frequency. Sound waves also have these three properties. Amplitude of Sound Waves
Like the other types of waves, the amplitude of sound waves is the size of the waves. But crests and troughs in sound waves are different from those in the other types of waves. Recall that the crests and troughs in sound waves are the areas where the matter pushes together and spreads out. The amplitude of sound waves is how much the matter pushes together at the crests and how much it spreads out at the troughs. If the matter pushes together a lot, the waves have a large amplitude. If the matter does not push together much, the waves have a small amplitude. Sound waves move through air. They are hard to see since you cannot see air. But you can hear sound waves! So, you measure the properties of sound waves by how they sound. Sound waves with large amplitudes are loud. The sound waves you make when you yell have large amplitudes. The matter pushes together a lot, so the sound is loud. Sound waves with small amplitudes are quiet. The sound waves you make when you whisper have small amplitudes. The matter does not push together much, so the sound is quiet. 44
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This student is playing a trumpet loudly. Do you think that the amplitude of the sound waves from the trumpet is large or small?
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Wavelength of Sound Waves
Frequency of a Sound Wave
Sound waves also have wavelength. Like the other examples of waves, the wavelength of sound waves is the distance between two crests that are next to each other. You listen to find the wavelength of a sound wave. A high-pitched sound has a short wavelength. A low-pitched sound has a long wavelength. Wavelength and amplitude are independent. A police siren is high pitched and loud. A bird chirping is also high pitched but soft. Thunder is low pitched and loud. A frog croaking is also low pitched but soft.
The frequency of a sound wave is how many crests pass a specific point in a certain amount of time. If you had the right tools, you could measure the frequency of a sound wave by counting how many waves entered your ear in a certain amount of time.
Frequency of Sound Waves
Sound waves also have a frequency, which is how many crests pass a specific point in a certain amount of time. Many people measure the frequency of sound waves as how many crests enter your ear in a second. In all waves, frequency and wavelength are dependent on each other. Two things are dependent when they affect each other. The wavelength of a wave affects its frequency. More waves will pass a given point in a certain amount of time if a wave has a short wavelength. So, a wave with a shorter wavelength will have a greater frequency. A wave with a longer wavelength will have a smaller frequency. High-pitched sounds have a high frequency. Low-pitched sounds have a low frequency. Š Teachers’ Curriculum Institute
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Think about each of the sounds described below. Then, match the amplitude and wavelength to each sound.
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1. Loud, high-pitched police siren
a) Small amplitude, short wavelength
2. Quiet, high-pitched bird chirping
b) Small amplitude, long wavelength
3. Loud, low-pitched thunder
c) Large amplitude, short wavelength
4. Quiet, low-pitched frog croak
d) Large amplitude, long wavelength
Lesson 2 What Are Some Properties of Waves?
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CHECK
FOR
UNDERSTANDING
Show What You Know Look carefully at these diagrams modeling three examples of waves. Then answer the questions below. Water Wave Crest
Sound Wave Rest Position
Crest
Wavelength Wavelength Trough
Trough Wave on a String Rest Position Wavelength
Crest
Wavelength Trough
Based on these diagrams, how can you describe wavelength in all waves?
What pattern would you see if the wavelength of all of these waves was increased?
What other properties can be used to describe waves? Explain.
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CHECK
FOR
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Making Sense of the Phenomenon Let’s revisit the phenomenon: Water waves can be big and fast enough to surf on. Think about: • Describe the amplitude of the wave the surfer surfs on. • Describe the wavelength of the wave.
Use your findings from the investigation to answer this question: What properties can be used to describe an ocean wave? Claim
Evidence
Reasoning
Go back to page 4 and fill out the unit checkpoint for this lesson. 48
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Lesson 6
How Can Patterns Be Used to Send Messages?
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Lesson 6 How Can Patterns Be Used to Send Messages?
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INVESTIGATION
Observing Phenomena Discuss: Do any of your family members or friends live far away? Do you stay in contact by calling, texting, or emailing them?
Observe this phenomenon: You can send messages to and receive messages from people who are far away.
Try It!
Send a text message or e-mail. How does the message travel from device to device so quickly?
Think of what you already know about how text messages, emails, and phone calls are able to travel so quickly. Write questions you have.
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INVESTIGATION
Defining the Problem In this investigation, you will design and test a digital device to send two types of messages: • Words in Morse code • A black and white picture using a grid of 1s and 0s Define the problem. What are the criteria for a successful digital device? What are the constraints? Criteria:
Constraints:
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Defining the Test Engineers test their solutions to determine which of them best solves the problem. After you have built your devices, we will test them. Here’s a basic summary of how the testing will work: • One group member will be the “receiver.” This student waits outside the classroom. • Each group will get a secret word and a picture. • Your group will have 3 minutes to code the message and picture for your device. • Then, the “receivers” will come back into the room. • You will have 4 minutes to send your message and picture to your “receiver.” We’ll see which groups sent the message and picture accurately!
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INVESTIGATION
Look at the Receiving Digital Messages handout. • The student receiving the test will use this handout. • The handout gives you the Morse code chart for translating the message and a grid for translating your digitized pictures. • You’ll be using a 12-by-12 grid. Keep your handout nearby for the tests.
Updating the Problem Now that you know how you’re going to test your devices, do you need to change the problem? Have your criteria and constraints changed? Update your criteria and constraints.
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Planning and Building a Solution Engineers often come up with many different solutions to a problem. Then, they compare these solutions based on how well they meet the criteria and constraints. Draw diagrams of three possible solutions to the problem. Label the materials you use in each digital device. Name each digital device. Name of Device 1: Diagram:
Name of Device 2: Diagram:
Name of Device 3: Diagram:
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INVESTIGATION
In your groups, compare your three design solutions. • What are the advantages of each? • What are the disadvantages? • Does one solve the problem better than the others? Choose one of the designs to build and test. Which design will the group build? Write its name below. Write a statement about why this device is the best solution.
You’ve picked your design. Now build it! Follow your diagram. Practice using your device. Let your teacher know when everyone is done. 116
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Testing the Solution Choose someone in your group to receive the test message and picture. (Go wait outside.) • Your teacher will distribute the secret message and picture. • Starting now, each group has 3 minutes to code the message and picture. Bring the ‘receivers’ back into the room. • Send your message and picture. You have 4 minutes starting now. • Who accurately sent the message? The picture? Let’s test again! Think about the testing process. In what ways did the device succeed? In what ways did it fail? Review your testing handouts.
Explain your test results. Use evidence from your test handouts.
Explain how you can improve your device. Use the problem’s criteria in your explanation.
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Vocabulary Match the term to its definition. Word Bank
digital device
telegraph
1. A device that uses digitized patterns to send and receive messages. 2. A device that sends electric signals over wires. People used Morse code to send information with this device.
My Science Concepts Reflect on your understanding. Draw an X along each line. Morse code is a digitized pattern. Talking drums use digitized patterns. Modern devices work by using digitized patterns of 1s and 0s. Examples are telegraphs, cell phones, radios, and computers. still learning
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Digital devices rarely mix up 1 and 0. They can send messages long distances using many 1s and 0s without mixing up the numbers. High-tech devices can receive and decode information—convert it from digitized form to voice—and vice versa. still learning
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Engineers generate and compare multiple solutions to find solutions to problems. Different solutions need to be tested to determine which of them best solves a problem, given its criteria and constraints. still learning 118
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1. Sending Words with Morse Code To communicate with someone far away, you might call or email them. But 150 years ago, sending messages long distances was much different. One way to send messages quickly over long distances was to use a telegraph. A telegraph is a device that sends electric signals over wires. You do not talk into a telegraph. It can only send electric signals. The first telegraph had 26 wires, one for each letter of the alphabet. In the 1830s, inventor Samuel Morse designed a telegraph that had only one wire. He created a digitized code, called Morse code, for this telegraph. It used a combination of dots and dashes to represent all 26 letters. Since his design had only one wire, it was easier to use than the first telegraph. When engineers compared the two designs, it was clear that Morse’s was a better solution to the problem of sending messages long distances. To send a message with a telegraph, a person translated a message into Morse code. Then they tapped the message into a telegraph. To make a dot, the person pressed the button for a short time. To make a dash, they pressed the button for a longer time. The telegraph receiving the signals would then write the dots and dashes on a piece of paper. Another person would then translate Morse code back into letters. Š Teachers’ Curriculum Institute
Telegraphs like this one were used to send messages long distances.
Although telegraphs are not used very much anymore, Morse code is still used today. Instead of telegraphs, Morse code today is transmitted over radios or through long and short flashes of light.
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Carefully read these passages about Morse code. Then, write a paragraph of your own answering this question: Should Morse code still be used today?
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Morse Code Still Useful!
Morse Code—Time to Let It Go!
After more than 170 years, Morse code is still used today. Some people still enjoy sending Morse code messages as a hobby. Morse code can be easier to interpret than a human voice if the signal is bad. Morse code can also be used to signal SOS if help is needed. SOS is recognized around the world as a distress signal. Some people who have been lost in the wilderness have been able to send an SOS message using a radio, a mirror, or a flashlight. Morse code can also be used by people with disabilities to send messages. They can tap out Morse code and it can be translated by a computer. In some cases, people have even used blinking to speak in Morse code!
Although Morse code served an important purpose many years ago, it is no longer useful today. Cell phones, satellites, and other technologies have replaced the need for Morse code. The U.S. Coast Guard no longer uses Morse code on the radio, and they no longer watch for SOS radio transmissions. Morse code is a very difficult “language” to learn. Although there are still people and websites who teach Morse code, they do it mostly for fun and to learn a skill. It is not worth the time it takes to send and decode long messages. Even when Morse code is used today, it is often translated by computers. It would be easier to use a system of 1s and 0s instead of Morse code.
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Your paragraph must: • explain your point of view in a topic sentence. • support your point of view with at least two reasons. • use information from at least two texts you have read about Morse code.
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2. Sending Pictures with a Telegraph You just learned how to send messages with a telegraph. What if you wanted to send a picture far away? You cannot use Morse code, but you can use electrical pulses to send a picture. One way you can send a black and white picture with a telegraph is to send it as dots and dashes. First, you need to draw a grid on the picture. The person at the other end of the telegraph needs a piece of paper with the same grid on it. Now look at the first square of the grid. If the square has more white, send a short pulse, or a dot, through the telegraph. If it has more black, send a long pulse, or a dash. The person reading the message then translates your dots and dashes. If the first pulse you send is a dot, they leave the first square on their grid white. If the first pulse is a dash, they fill in the square black. Repeat this method for each square. After, they should have a picture that is similar to yours. Sending a picture this way is an example of digitizing because each square is represented by only one color. In other words, a square of the grid on the original picture might have mostly black but a little white. But you send a dash so that the square is translated as only black. You digitize the picture because it makes it easier to communicate over long distances. 122
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You can communicate whether each square of the grid has more black or white using a dot or a dash. Then send the dots and dashes through a telegraph, so a person on the other side can recreate the image.
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Explain how you could send a picture using only short and long electric signals. Include these terms in your answer: grid, dot, dash, and digitize.
When you digitize a picture, will it look exactly like the original picture? Why or why not?
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3. Sending Messages as 1s and 0s Think about the patterns used to send messages. You have learned about high- and low-pitched drums, long and short electric pulses, and dots and dashes. What do all of these patterns have in common? All of these patterns have two parts. The drums are high and low pitched. The pulses are long and short, or dash and dot. There is another two-part code that is a pattern of 1s and 0s. It can communicate the same messages as the other patterns. Like the other patterns, sending messages with 1s and 0s is an example of digitizing. You can translate Morse code into 1s and 0s to send words. The number 1 can represent a long pulse, or a dash. The number 0 can represent a short pulse, or a dot. Try to write the word “wave” with 1s and 0s. First, use the Morse code chart to translate each letter into Morse code. You should have found that “wave” translates into •—— •— •••— •. Then write each dash as a 1 and each dot as a 0. Morse code is a pattern that has two The word becomes 011 01 0001 0. Now you parts. You can translate words from have written “wave” in 1s and 0s. letters into Morse code, then from You can also draw pictures using a grid Morse code into 1s and 0s. This table of 1s and 0s. Remember the picture you sent shows a few examples. using a telegraph? You can use the same method Letters Morse Code 1s and 0s to send pictures using 1s Wave • • ••• • 011 01 0001 0 and 0s. If a square on the Tree • • • • 1 010 0 0 picture has more black, Code • • •• • 1010 111 100 0 Book ••• • 1000 111 111 101 it is a 1. If the square has Phone • • •••• • • 0110 0000 111 10 0 more white, it is a 0.
–– – – – – – – ––– – – ––– ––– – – –– ––– –
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This message is written in 1s and 0s. To figure out what it says, translate each letter into Morse code. Then translate the Morse code into letters of the alphabet. 0110 01 1 1 0 010 10 000 11 0 000 000 01 110 0 000
1010 01 10
000 0 10 100
Write the message you decode here:
Use the code to figure out what this picture represents. Remember, this is similar to what computer monitors do! Shade all the cells that are 1s in the code black. Leave all the cells that are 0s in the code white.
Then describe what you see in the picture.
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4. Digital Devices Use Digitized Messages Many modern devices send and receive digitized messages. Cell phones and radios are digital devices. So are computers. Many cars even use digitized messages. A device that uses digitized patterns to send and receive messages is called a digital device. Most digital devices use patterns of 1s and 0s that are electrical signals. When the signal is on, it is a 1. When the signal is off, it is a 0. Digital devices send information that is represented by 1s and 0s. For instance, each letter in the alphabet is represented by a combination of 1s and 0s. Digital devices use 1s and 0s because they can be sent quickly and easily. Digital devices rarely mix up 1 and 0. They can send messages long distances that use many 1s and 0s without mixing up the numbers. This is why if you send a picture to a friend, it looks the same on your friend’s device as it does on yours. Cell phones are one example of a digital device that uses 1s and 0s. When you speak into a cell phone, the phone’s microphone turns the sounds into a pattern of 1s and 0s. Then it sends this pattern through the air to another cell phone. Since the message is digitized, it is sent very quickly and without mistakes. When another cell phone receives the messages, it turns the digitized messages back into sounds. 126
Lesson 6 How Can Patterns Be Used to Send Messages?
Cell phones digitize sound into 1s and 0s. Then they send them through the air and change them back into sounds so that you can hear someone who is far away talk to you.
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NOTES
When reading text, it is important to make inferences. An inference is a logical conclusion that can be made based on the evidence in the text. Inferences are not stated directly in the text. But the text can give hints about other things that might be true. You must be able to support your inference with details from the text! Often, you can combine two different sentences in a text to come up with a reasonable inference. After reading the Section 4 text, a student wrote the following inference: “Radios can accurately send and receive digital messages over long distances.” What details or examples in the text support this inference? Write them in the space below.
The text specifically states that computers are digital devices. Based on what the text says about other digital devices, what inferences can you make about computers? Write your inference below and then explain which details in the text support your inference.
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Lesson 6 How Can Patterns Be Used to Send Messages?
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CHECK
FOR
UNDERSTANDING
Show What You Know Use this code to reveal an image. Code: 1 = black square, 0 = white (empty) square After you have decoded the image, write a caption that describes the image.
Now, turn a picture into code! • Write out a code, using dots and dashes, that would send this picture of a rabbit over a telegraph. • For each square that is mostly black, record a dash. For each square that is mostly white, record a dot. • Finally, using the code you just wrote out, create a digitized picture to see what it looks like.
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Lesson 6 How Can Patterns Be Used to Send Messages?
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FOR
UNDERSTANDING
Making Sense of the Phenomenon Let’s revisit the phenomenon: You can send messages to and receive messages from people who are far away. Think about: • How do phones digitize messages? • Other than text messages, what are other ways you can communicate with a digital device? Use your findings from the investigation to answer this question: How do digital devices improve communication? Claim
Evidence
Reasoning
Go back to page 4 and fill out the unit checkpoint for this lesson.
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Performance Assessment:
Developing a Communication Method Using Waves Help Billy understand sound waves by modeling how they work. Then, create a new method of communication that uses other types of waves to send a message. You will: • use analogies or examples to model the properties of sound waves. • design a communication method using patterns to send messages without the use of sound waves. • test and compare your communication method to improve your design.
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Performance Assessment: Developing a Communication Method Using Waves
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PERFORMANCE ASSESSMENT
Developing a Model for Sound Waves Sound waves move through the air around us. While we can not see these waves, we can hear them or even feel them. What patterns are common in sound waves? Create an analogy to model how sound waves work. Think of something that you can compare a sound wave to. Then, fill in the table below to help you create an analogy for a sound wave. Your analogy should explain how your choice for comparison also demonstrates wave properties and their ability to make objects move.
Sound waves
are like
They have wavelengths
which are like
and amplitudes
which are similar to
and frequencies
which can be compared to
Sound waves can also make objects move
like
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Performance Assessment: Developing a Communication Method Using Waves
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PERFORMANCE ASSESSMENT
How does your analogy show that sound waves have patterns?
Think about the other two types of waves that we learned about. Create an analogy that models how water waves and waves on a string move. How water waves move:
How waves on a string move:
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Performance Assessment: Developing a Communication Method Using Waves
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PERFORMANCE ASSESSMENT
Developing a Communication Method Most people communicate with others by talking. Sometimes, people can’t use sound waves to communicate. They might not be able to speak. The person they are communicating with may also be unable to hear. What other ways can we use waves, or their properties, to help us communicate? With a partner, design a communication method using waves. Your design should meet the following criteria and constraints: • Be able to send simple messages • Use waves or wave properties • Not be too difficult to learn or follow • Not require too many materials to use Write about your method below.
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Performance Assessment: Developing a Communication Method Using Waves
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PERFORMANCE ASSESSMENT
Testing your Communication Method Test your communication method! If your communication method requires materials, you may use them now. When you are ready, try sending the message: Hello friend After you test your communication method with your partner, discuss how your test went. Make changes to your model as needed. Then, fill in the chart below to determine how well you met the criteria and constraints.
Criteria 1: Method must be able to send simple messages.
Criteria 2: Method uses waves or wave properties to send message.
Constraint 1: Constraint 2: Method Method must must not not require be difficult too many to learn or materials to follow. use.
Your group’s method
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Performance Assessment: Developing a Communication Method Using Waves
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Performance Assessment: Developing a Communication Method Using Waves
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Grade 4 TCI’s Grade 4 program includes four units. Each unit has a Science Journal, complete with hands-on investigations, text with notes, and checks for understanding.
Unit 4
Unit 1 Plant and Animal Structures 1 What Plant Structures Are Used for Support and Growth?
6 What Animal Structures Are Used for Support, Movement, and Protection?
2 What Plant Structures Are Used for Protection?
7 What Animal Structures Are Used for Reproduction?
3 What Plant Structures Are Used for Reproduction?
8 What Animal Structures Are Used for Sensing the
4 How Do Plants Respond to Their Environment? 5 What Animal Structures Are Used for Digestion and Circulation?
Grade 4
Waves and Information Science Journal
Environment? 9 How Do Animals Respond to Their Environment? Performance Assessment: Designing a Legendary Creature
Unit 2 Energy 1 How Are Energy and Motion Related? 2 How Is Energy Transferred by Colliding Objects?
Performance Assessment: Creating a Safety Pamphlet
3 How Is Energy Transferred by Sound, Light, and Heat?
5 How Is Energy Stored and Used?
4 How Is Energy Transferred by Electric Currents?
6 How Do People Choose Energy Resources?
Performance Assessment: Designing a Safety Device
Unit 3 Earth’s Changing Surface 1 What Are Some Clues That Earth’s Surface Changes? 2 How Does Water Change Earth’s Surface? 3 How Does Wind Change Earth’s Surface?
Performance Assessment: Investigating Changes to the Appalachian Mountains 6 Where on Earth Are Earthquakes, Volcanoes, and Mountains Found?
4 How Do Living Things Change Earth’s Surface?
7 What Can People Do About Natural Hazards?
5 How Do Fossils Form and What Do They Show?
Performance Assessment: Developing Hazard Plans
Unit 4 Waves and Information 1 What Are Some Examples of Waves?
5 How Can Sound Waves Be Used to Send Messages?
2 What Are Some Properties of Waves?
6 How Can Patterns Be Used to Send Messages?
3 How Do Waves Affect Objects?
Performance Assessment: Developing a
4 Which Waves Travel Through Earth?
Communication Method Using Waves
Engineering
Name: