Science through LEGO Engineering Design a Musical Instrument: The Science of Sound. Curriculum Resources Edition

Transcription

1 Science through LEGO Engineering Design a Musical Instrument: The Science of Sound Curriculum Resources Edition Contributors: G. Michael Barnett, Ph. D., Boston College Kathleen Connolly, Tufts University Linda Jarvin, Ph. D., Tufts University Chris Rogers, Ph. D., Tufts University Kristen Bethke Wendell, Tufts University Chris Wright, Tufts University The preparation of this curriculum was partially supported by grant DRL from the National Science Foundation. Grantees undertaking such projects are encouraged to express freely their professional judgment. This curriculum, therefore, does not necessarily represent the position or policies of the National Science Foundation. Not for distribution without the authors permission

2 Table of Contents for this Resource Packet Section 1. Teacher s Guide Section 2. Student Handouts for All Lessons Section 3. Supplemental Teacher Resources

3 Section 1: Teacher s Guide

4 Science through LEGO Engineering Module Overview Sound: Design Musical Instruments Lesson Title 1 How can we make different sounds and notes? 2 Why do instruments need sturdy frames? 3 How are a sound s vibration size and volume related? 4 What do sound vibrations travel through? 5 How do length and thickness affect pitch? Lesson Overview Students will be introduced to the design challenge of creating LEGO instruments. Then, in a mini-design challenge, they will explore how to make different sounds with only two objects (a plastic cup and plastic spoon). The primary goal of this lesson is for students to improve their ability to recognize and articulate what they notice about different sounds and how the sounds are produced. Students will practice using LEGO materials to build sturdy frames for musical instruments. They will discover the different roles LEGO beams, plates, axles, connector pegs, and bushings play in holding LEGO structures together. Specifically, students will be challenged to build LEGO triangles and rectangular prisms (boxes). Students will make LEGO drums by adding balloon membranes to their LEGO triangles. Then, they will observe vibrating drum membranes by sprinkling sugar on the membrane and watching the sugar bounce up and down. They will perform the vibration observations for both loud and soft sounds. This lesson expands on what students learned in Lesson 3 about the importance of vibrations to sound. The focus of the investigation shifts from the source of sound vibrations to the transmitter of sound vibrations. Students will continue to use the LEGO drums built in the previous lesson to explore the transmission of vibrations through air (gases), solids, and liquids. They will also build pan pipes to prepare for the investigation to be conducted in Lesson 5. This lesson is the first of two that focus on the pitch of sound. Students will explore the effect of length and thickness on pitch by building a two-string guitar with a rubber band and a LEGO frame. The strings will have different thickness to allow students to observe the effect of thickness on pitch. They will use connector pegs as guitar frets, which will allow them to vary the length of the guitar string without changing its tension. Lesson Learning Objectives Students will be able to: Distinguish between high-pitched and low-pitched sounds. Combine different shapes and structures to design and build frames for sound-makers. Recognize that vibrations are responsible for the production of sound. Indicate that volume is determined by the size of sound vibrations. Explain how sound vibrations are transmitted through solid, liquid, and gas mediums. Indicate that pitch is determined by the speed of vibrations. Discuss the effect on pitch of changing the length or thickness of a vibrating object.

5 Science through LEGO Engineering Module Overview Sound: Design Musical Instruments Lesson Title 6 How does tension affect pitch? 7 What happens when a sound is reflected, absorbed, or transmitted? 8 How can we make one instrument that plays three different pitches? 9 What are all the different ways to make one instrument that plays three pitches? Lesson Overview This lesson is the second of two that focus on the pitch of sound. Students will explore the effect of tension on pitch by building a onestring guitar with a rubber band, LEGO frame, and LEGO motor. They will wind one end of the rubber band around an axle attached to the LEGO motor. The motor will allow them to vary the tension of the guitar string without changing its length or width. Students will build a LEGO rattle, or maraca, and will measure its noise output with a LEGO NXT sound sensor. They will investigate what happens when they muffle the maraca with their hands. The hand muffler activity is intended to help students explore how sound can be absorbed, reflected, or transmitted as it travels away from its source. Students will design and build their own LEGO instruments. They will use what they have learned by building the previous research instruments. However, their instrument must be a new invention, and it must play at least three different pitches. Students will demonstrate these instruments by using them to play a song for the class. Students will complete posters that explain how their instrument makes at least three different pitches. Then, the culminating event of the module is an engineering design expo in which students demonstrate their instruments and explain the design features that produced the three different pitches. Lesson Learning Objectives Students will be able to: Indicate that pitch is determined by the speed of vibrations. Discuss the effect on pitch of changing the tension of a vibrating object. Predict if a sound will be reflected, absorbed, or transmitted through a given medium. Explain that sound is a form of energy. Combine different materials, shapes, and structures to design and build sound-makers with many different volumes and pitches. Define engineering design as the process of creating solutions to human problems through creativity and the application of math and science knowledge, and list and explain the steps of the engineering design process. Combine different materials, shapes, and structures to design and build sound-makers with many different volumes and pitches. Define engineering design as the process of creating solutions to human problems through creativity and the application of math and science knowledge, and list and explain the steps of the engineering design process.

6 Learning Objectives for Science through LEGO Engineering Sound: Design a Musical Instrument By the end of the module, students will be able to: 1) Recognize that vibrations are responsible for the production of sound 2) Explain how sound vibrations are transmitted through solid, liquid, and gas mediums 3) Distinguish between high pitched and low pitched sounds 4) Indicate that pitch is determined by the speed of vibrations 5) Indicate that volume is determined by the size of vibrations 6) Discuss the effect on pitch of changing the length, tension, or thickness of a vibrating object 7) Predict if a sound would be reflected, absorbed or transmitted through a given medium 8) a) Explain that sound is a form of energy b) Explain that the amount of energy is determined by the size of the vibrations 9) Combine different materials, shapes, and structures to design and build sound-makers with many different volumes and pitches 10) a)define engineering design as the process of creating solutions to human problems through creativity and the application of math and science knowledge. b) List and explain the following steps of the engineering design process: i. Identifying a problem ii. Researching possible solutions iii. Picking the best solution iv. Building a prototype v. Testing the prototype vi. Repeating any steps needed to improve the design

7 Sound: Design a Musical Instrument Related National, State, and District Learning Standards Design a Musical Instrument Learning Objectives By the end of this module, students will be able to: 1) Recognize that vibrations are responsible for the production of sound 2) Explain how sound vibrations are transmitted through solid, liquid, and gas mediums 3) Distinguish between high pitched and low pitched sounds 4) Indicate that pitch is determined by the speed of vibrations 5) Indicate that volume is determined by the size of vibrations 6) Discuss the effect on pitch of changing the length, tension, or thickness of a vibrating object 7) Predict if a sound would be reflected, absorbed or transmitted through a given medium 8) a) Explain that sound is a form of energy b) Explain that the amount of energy is determined by the size of the vibrations 9) Combine different materials, shapes, and structures to design and build sound-makers with many different volumes and pitches 10) a) Define engineering design as the process of creating solutions to human problems through creativity and the application of math and science knowledge. b) List and explain the following steps of the engineering design process: i. Identifying a problem ii. Researching possible solutions iii. Picking the best solution iv. Building a prototype v. Testing the prototype vi. Repeating any steps needed to improve the design National AAAS Benchmarks 4.F.2 nd Grade - Things that make sound vibrate. National Science Education Standards Content Standard B: Position and Motion of Objects (K-4) - Sound is produced by vibrating objects. The pitch of the sound can be varied by changing the rate of vibration. Massachusetts Frameworks Grades 3-5, Strand 3: Physical Science - Identify the basic forms of energy (light, sound, heat, electrical, and magnetic). Recognize that energy is the ability to cause motion or create change. - Give examples of how energy can be transferred from one form to another. - Recognize that sound is produced by vibrating objects and requires a medium through which to travel. Relate the rate of vibration to the pitch of the sound. Somerville Science Benchmarks Sound Learning Standards, Grade 3 - Recognize that sound is produced by vibrating objects and requires a medium through which to travel. Relate the rate of vibration to the pitch of the sound. Sound Benchmarks, Grade 3 - Begin to understand that sound is a form of energy. - Demonstrate that sound is produced by vibration. - Begin to recognize that sound can travel through solids, liquids, or gases, but no through completely empty space. - Describe how to change the pitch of a vibrating string. - Predict which metal bar when hit will produce the lowest and the highest pitches.

8 Science through LEGO Engineering Design a Musical Instrument Lesson 1 How can we make different sounds and notes? Suggested Time Lesson Overview Learning Objectives Teacher Background One 60-minute session!!!!! Students will be introduced to the design challenge of creating LEGO instruments. Then, in a mini-design challenge, they will explore how to make different sounds with only two objects (a plastic cup and a plastic spoon). The primary goal of this lesson is for students to improve their ability to recognize and articulate what they notice about different sounds and how the sounds are produced.! Introduction to the design challenge and big science question! Brainstorming what we know and what we need to learn! Making and describing different sounds with cups and spoons! Class discussion about describing sounds!!!!! By the end of this lesson, students will be able to:! Distinguish between high-pitched and low-pitched sounds.!!!!! There are three requirements for sound to take place in an environment: (1) a vibrating source to start sound, (2) a medium to transmit sound vibrations throughout the environment, and (3) a receiver to hear or record sound vibrations. Sound is started in an environment by a vibrating source. There are numerous and varied vibrating sources pushing air past vocal cords, plucking a stretched string, striking a membrane of animal hide or synthetic material, buzzing lips on an instrument, and many other natural vibrating sources. Sound may also be produced by electronic vibration sources whirling of machines, playing of electronic keyboards and synthesizers, pulsing speakers, and more. Sound is generally measured by the number of vibrations per second produced by a vibrating body or source. If the vibration occurs at a steady number of vibrations per second, the musical effect produced is known as a pitch, tone, or note. Not all vibrations create sounds that humans can hear. Human ears sense vibrations only that are moving at speeds between 20 vibrations per second and 20,000 vibrations per second. If a vibration is too fast or too slow, it will not be heard as sound by humans. One vibration too fast for human hearing is the ultrasonic signal emitted by bats for echo-locating. Vibrations that are too slow for human hearing include ocean waves and earthquakes. We detect these vibrations by seeing and feeling them, but we do not hear them. The physical properties of vibrating objects come into play when 1-1

9 Science through LEGO Engineering Design a Musical Instrument Lesson 1 How can we make different sounds and notes? comparing the pitch of one vibrating object to another. Smaller, thinner, or tighter vibrating objects are higher in pitch, and conversely, larger, thicker, and looser vibrating objects are lower in pitch. Vocabulary Materials Preparation Instructions for Teachers GETTING STARTED Sound - Energy transported when object vibrates in a medium. Musical Instrument - A device used for making music. Engineer - A person who creates solutions to human problems through creativity and the application of math and science knowledge. For each student! Engineer s Journal Part 1 For each student pair! Disposable plastic cup (any size)! Disposable plastic spoon For the class! Simple non-electronic instrument such as a recorder, harmonica, xylophone, or guitar! Practice playing a short tune on a simple musical instrument.! Use chart paper or a large section of the board to make a sound description chart.! Arrange students in pairs.! Distribute Engineer s Journals. PART I: Module Introduction (20 min) What Do Children Think About Describing Sounds?! Some children have difficulty hearing the difference between sounds. Music instructors suggest that teachers encourage students to practice attentive listening.! Many kindergarten children think that sounds live in objects, go out to human ears, and then return home when objects are silent.! Fifth- and sixth-graders often conceive of sound as a repeated tapping, or resonating, that radiates out through air.! Third-graders usually do not have a universal theory of sound. They might apply the living sound idea to explain one kind of sound but apply the tapping sound idea to another kind of sound. 1) The lesson begins with a musical selection performed by you! Explain to the students that you are about to play them a tune. While they listen, they should think about how the instrument is making its sounds. What is happening to make the sounds of the song? 2) Ask students to listen and watch carefully as you play a song or a few notes on a recorder, harmonica, xylophone, guitar, or other simple non-electronic instrument. 3) Present students with the big science question: how are sounds made? Give students four or five minutes to talk to their partners about how instruments make sounds and then write or draw their ideas on page 1-1 of their Engineer s Journal. 1-2

10 Science through LEGO Engineering Design a Musical Instrument Lesson 1 How can we make different sounds and notes? ACTIVITY EXPLANATION 4) Present students with the grand engineering design challenge for this science module: Each pair of students will design and build a LEGO musical instrument that can play at least three different notes. 5) Give students four or five minutes to talk to their partners about what science ideas they already know that will help with their design and what science ideas they need to learn. Have students write their ideas on page 1-2 of their Engineer s Journal. 6) Explain that it is okay if students were not confident about the answers they wrote and drew, or if they have a long list of things they need to learn. After all, the purpose of the unit is to learn more about sound. Students will do this learning by becoming instrument engineers. 7) At this point, you might want to review briefly the plan for the entire module. Remind students that the first part of the engineering design process involves gathering information about how sounds are made. Students will gather information by constructing several simple instruments, each of which will help them learn something new about sound. By the end of the module, they ll know enough about sound to build their own more complicated, multi-note instrument. PART II: Sound Exploration (25 min) 8) Explain that before students gather information about instruments, they need to gather more information about different kinds of sounds, because they ll need to decide what kinds of sounds they want their instrument to make and how to make the sounds. They will also need to be able to describe the sounds of other students instruments. 9) Today students will learn more about sound by exploring how to make many different notes. Explain that the minichallenge for this lesson is to make at least three different notes using only a plastic cup and a plastic spoon. What Questions Might Students Ask During this Lesson?! How can we make three sounds with only two materials? Use as many different PARTS of the two materials as possible, and try to use the spoon in many different WAYS.! How do we know if we found the right sounds? There are not right and wrong sounds. What is important today is that you can explain why your sounds are different from each other and describe your sounds. 10) Model one way to make and describe a sound. Make an example sound by using the handle of the spoon to tap on the bottom of the plastic cup. This is the sound described in the first column of the sound description chart found on page 1-3 of their Engineer s Journal. 1-3

11 Science through LEGO Engineering Design a Musical Instrument Lesson 1 How can we make different sounds and notes? STUDENTS INDEPENDENT ACTIVITY MAKING SENSE OF THE ACTIVITY Note: Try to model three different approaches to describing sounds: onomatopoeia words (bing, kerplop, smoosh, etc.), adjectives (tinny, whiny, calm, timid, loud, quiet, etc.), and similes (like a pin dropping, like a baby crying, like footsteps up stairs, etc.). Note: During this class discussion, look for opportunities to introduce the terms low pitch and high pitch. If students do not use them on their own demonstrate and describe sounds that are especially high or low. 11) Work with the students to answer: How would you tell someone else about the sound? Students should record the class way to tell someone else about the sound on page 1-3 of their Engineer s Journal. 12) Distribute one cup and one spoon to each student pair. 13) Allot 10 minutes for students to work with their partners to make and describe as many sounds as possible. PART III: Class Discussion of Sound Descriptions (15 min) 14) Gather students together and direct students toward the large class version of the sound description chart. 15) Ask students to describe some of their favorite sounds that they made. Record their descriptions on the class chart, paying particular attention to how students would tell someone about their sounds. 16) As students share how they listened for, made, and described sounds, encourage other students to ask for clarification if they do not understand a description. Encourage other students to suggest additional words that would help with the descriptions or ways to tell someone else about the sound. 17) If you have extra time, conduct a brief brainstorming session on any other words that might be useful for describing sounds. 18) Conclude by encouraging students to keep thinking about what kinds of sounds they will want their musical instruments to make. 1-4

12 Science through LEGO Engineering Design a Musical Instrument Lesson 2 Why do instruments need sturdy frames? Suggested Time Lesson Overview Learning Objectives Teacher Background Vocabulary One 60-minute session!!!!! Students will practice using LEGO materials to build sturdy frames for musical instruments. They will discover the different roles LEGO beams, plates, axles, connector pegs, and bushings play in holding LEGO structures together. Specifically, students will be challenged to build LEGO triangles and rectangular prisms (boxes).! Listening to musical instruments (with audio CD)! Discussion of musical instrument frames! Explanation of LEGO sturdy shape challenge! Building, testing, and diagramming LEGO sturdy shapes! Discussion of lessons learned about LEGO instrument frame building!!!!! By the end of this lesson, students will be able to: Combine different shapes and structures to design and build frames for sound-makers.!!!!! When constructing sound-making devices, it is important to know that to create vibrations there must be a certain amount of surface tension in the vibrating body. Solid objects have inherent tension. Soft objects like strings or membranes must be stretched to create the tension required to support vibrations. The sturdy frames constructed by students in this lesson are essential bases for LEGO instruments that students will make. To turn balloons into drums (Lessons 3 and 4), or rubber bands into guitars (Lessons 5 and 6), students will need strong frames capable of holding the tension of stretched rubber. Real-world musical instruments come in a huge variety of shapes and sizes, but they all have one thing in common: a strong underlying structure.!!!!! Frame A case or structure for holding or supporting something. Shape The configuration or form of an object. Triangle A completely enclosed shape with three straight sides that are connected at three different points. 2-1

13 Science through LEGO Engineering Design a Musical Instrument Lesson 2 Why do instruments need sturdy frames? LEGO beam - LEGO rounded beam - LEGO brick - LEGO plate - LEGO axle - LEGO short connector peg - LEGO long connector peg - What Do Children Think about Sturdy Shapes?! Some students assert that the best shape is simply the most interesting or intricate shape (e.g., octagonal dome, hemisphere).! Many students think that the square is stronger than the triangle. Materials LEGO bushing - For each student! Engineer s Journal Part 2 For each student pair! LEGO Mindstorms Kit Preparation Instructions for Teachers For the class! Transparencies or print-outs of pictures of musical instruments (drum, harmonica, harp, and upright piano)! Transparencies or print-outs of sample diagrams! Audio CD of musical instrument sounds (optional)! Distribute Engineer s Journals.! If planning to use the audio CD during the introduction (Step 6), plug in a CD player in a location where all students will be able to hear it. PART I: Introduction (15 min) 1) Give students two to three minutes to talk with their partners and then write and draw their ideas about today s exploration question: Most musical instruments are made out of metal, wood, or plastic. Why are instruments made out of these materials instead of paper or cloth? Students should write and draw their ideas on page 2-1 of their Engineer s Journal. 2-2

14 Science through LEGO Engineering Design a Musical Instrument Lesson 2 Why do instruments need sturdy frames? GETTING STARTED ACTIVITY EXPLANATION 2) Ask a few students to explain their thoughts on this question. Then, if no one has mentioned the strength of metal, wood, and plastic, clarify that these materials are useful for instruments because they are strong. Instrument frames need to be strong because they must support large pushes and pulls, both from the musicians that play the instruments and from the strings or membranes that are stretched across the frames. For example, a guitar s strings are stretched tightly, and materials like paper or cloth could not support their tension. 3) Explain that, in addition to being strong, instrument frames have different shapes to create different sounds. Engineers who design musical instruments must determine which frame shapes make the best sounds. 4) Explain that today s activity will help students learn how to build strong shapes for their LEGO instruments. To start thinking about instrument shapes, the class will now look at images of musical instruments and describe the shapes of their frames. 5) Display each musical instrument image, one at a time. Ask students to describe the instrument s shape. Record their shape words on the board, chart paper, or overhead projector. What Questions Might Students Ask During this Lesson?! How can I make my LEGO shape sturdier? Connect pieces together in two places instead of one.! How can I keep my shape from collapsing? Connect pieces more rigidly by adding more attachment points.! When I put an axle through these two beams, why do they rotate around each other? To be fixed in place, beams must be attached in at least two places. 6) (If desired, you might use the provided audio CD to play a brief recording of each instrument as the students study its image. It is important to explain, however, that most of the time an instrument s shape cannot be identified by its sound.) 7) We have provided images for these instruments: drum (circle), harmonica (rectangle), harp (triangle), and upright piano (box). 8) Conclude the introduction by reiterating that students might use one or more of these shapes in their LEGO musical instruments. PART II: Sturdy Shape Building (30 min) 9) Ask students to turn to page 2-2 in their Engineer s Journal. 10) Review with students the instructions for the sturdy shape challenge. Point out the example diagram and ask students to identify the key parts of the diagram. If not mentioned by students, draw their attention to the diagram s inclusion of: (1) only the essential LEGO 2-3

15 Science through LEGO Engineering Design a Musical Instrument Lesson 2 Why do instruments need sturdy frames? elements, (2) labels for the name and size of each element, (3) arrows connecting each label to its part, and (4) title. You might show additional sample diagrams using the provided transparencies or created by yourself. 11) Explain that if students cannot figure out how to make a shape on their own, they can use the Building Hints section of their Engineer s Journal. 12) Remind students how connector pegs, axles, and bushings can be used to connect LEGO beams and plates together. STUDENTS INDEPENDENT ACTIVITY Note: You could set up a drop-test area of the classroom where students can go to drop their shapes from a teacher specified height. MAKING SENSE OF THE ACTIVITY 13) Allot 20 minutes for students to build and diagram sturdy triangles and boxes. 14) Remind students to conduct the Drop Test (drop from waist height) on each shape to prove its sturdiness. 15) Allow students to keep their constructions intact because they will be used during future lessons (e.g., the triangle will be used in lesson 3 and the box in lesson 7). PART III: Discussion of Lessons Learned about LEGO Building (10 min) 16) Gather students together. Ask for volunteers to describe what they learned from building LEGO shapes that might help them or their classmates build LEGO instruments later. 17) Conclude by telling students that they will use their new LEGO building skills in the next lesson, when they build their first LEGO instrument a drum. 2-4

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23 Science through LEGO Engineering Design a Musical Instrument Lesson 3 How are a sound s vibration size and volume related? Suggested Time Lesson Overview Learning Objectives Teacher Background One 60-minute session!!!!! Students will make LEGO drums by adding balloon membranes to their LEGO triangles. Then, they will observe vibrating drum membranes by sprinkling sugar on the membrane and watching the sugar bounce up and down. They will perform the vibration observations for both loud and soft sounds.! Thinking about how a drum works! Guided demonstration of balloon as drum membrane! LEGO drum building! Drum vibration observation! Class discussion about sound vibrations and volume!!!!! By the end of this lesson, students will be able to: Recognize that vibration is responsible for the production of sound. Indicate that volume is determined by the size of sound vibrations.!!!!! Sound is caused by vibrations produced by a source, transmitted through a medium, and detected by a receiver. The amplitude (size) of a vibration determines the loudness and softness of sound. The loudness or softness of a sound is commonly known as its volume. A louder sound has a wider vibration than a softer sound. The figure below shows a comparison between a loud and soft sound. Smaller vibrations are equivalent to softer sounds, while larger vibrations are equivalent to louder sounds. Volume depends on the amount of the force used to start the sound vibrations. The more force used to start the vibrations, the louder the sound produced. For example, the volume of an acoustic guitar is determined by the force with which the string is plucked. When studying sound-making devices, it is important to pay close 3-1

24 Science through LEGO Engineering Design a Musical Instrument Lesson 3 How are a sound s vibration size and volume related? attention to the source of the vibrations, which is the initially vibrating substance. Correctly determining the source is vital to drawing accurate conclusions about the type of sound that will be made. Vocabulary Materials Preparation Instructions for Teachers GETTING STARTED!!!!! Vibration - Rapid and steady back and forth motion. Membrane - A thin, soft, flexible layer, often made by stretching a thin material tightly over an object. Volume - How loud or soft a sound is. For each student! Engineer s Journal Part 3 For each student pair! LEGO Mindstorms Kit! (1) 9-inch balloon, un-inflated, with a slit cut in the side For the class! (2) packets of sugar substitute (e.g., Equal, Sweet & Low, etc.)! Pre-built LEGO drum example! Cut a slit from the opening to the round part of each balloon.! Build a LEGO drum example.! Arrange students in pairs.! Distribute Engineer s Journals. What Do Children Think about the Cause of Sound? Third-grade and younger children have many different ideas about how sounds are made. They include:! Sound is caused by blowing wind.! Musical sound is caused by pushing against instruments.! Sound comes in tiny pieces that blow off of instruments; these pieces are invisible, and they fly through the air.! Human actions, such as striking a drum, cause sound. The structure of the object being struck does not matter.! Once a sound has been created, it is a substance. It has weight and permanence.! Sounds are caused by vibrations (without any idea of what vibration means). PART I: Introduction and Exploration of Balloon Drumheads (15 min) 1) Give students two to three minutes to talk with their partners and then write or draw their ideas about today s exploration question: How does a drum make its sound? How do you know? Students should record their ideas in their Engineer s Journal. 2) Explain that today is part of the research phase of the engineering design process for their instrument challenge. Their investigation will focus on how drums make sounds that our ears can hear. When they design and build their final instruments, they will use the information they learn during their research. 3) Explain that in this lesson, students will make miniature drums out of their LEGO triangles and balloons. 4) Distribute pre-slit balloons and LEGO kits. 3-2

25 Science through LEGO Engineering Design a Musical Instrument Lesson 3 How are a sound s vibration size and volume related? Note: Be sure students use connector pegs with friction (typically black) rather than axle-connector pegs (typically blue or beige), which will not sufficiently attach the balloon to the beam. 5) Ask students to follow along as you model the procedure for connecting a balloon membrane to a LEGO beam. One student in each pair should hold a LEGO beam in place. The other student should hold one edge of the balloon over the beam and place a black connector peg through the balloon and into a hole in the beam. Then, they should switch jobs and repeat the process so that the balloon is attached to the beam in at least two places. Students should only attach one side of the balloon to the beam in order to do the next activity. What Questions Might Students Ask During this Lesson? Note: For better results, you may suggest students use a pencil or LEGO beam for tapping on the stretched balloon. Figure 1. How to practice using a balloon as a drum membrane 6) Once students have mastered attaching a balloon to a LEGO beam, have them investigate the effect of stretching the balloon membrane. Ask one student to hold the beam while the other student holds the opposite (unattached) end of the balloon membrane. Have this student gradually stretch out the balloon while the other student taps on the balloon membrane. Direct students to listen for the sound made by tapping on the balloon membrane.! Why won t my partner let me build anything? You need to take turns putting pieces on your drum. After you add one piece, pass the drum and the LEGO kit to your partner for his or her turn.! How do we put the connector peg through the balloon? You don t need to punch a hole in the balloon with the peg. Use the peg to push the balloon into one of the beam holes.! Why doesn t our drum make any sound? Your balloon might not be stretched tightly enough. Make sure your shape is sturdy. THEN stretch your balloon around it, and add pegs to hold it in place. 7) Tell students to switch who is holding the beam in place and who is stretching the balloon and listening so that each student has the opportunity to do both. 8) Ask students, How did the sound change as you stretched out the balloon? Help students discover two main principles: a. The balloon needs a tightness (or tension) before it will make a decent musical sound. When the balloon is held loosely, it does not sound like a drum when it is tapped. (Later, students will learn 3-3

26 Science through LEGO Engineering Design a Musical Instrument Lesson 3 How are a sound s vibration size and volume related? that this is because the balloon must vibrate to make a musical sound. When it is too loose, it moves only in one direction when tapped, rather than repeatedly moving back and forth.) When building LEGO drums, students must be sure to stretch their balloon tightly enough. b. Once the balloon is stretched tightly enough to make a musical sound, the pitch of the sound increases as the tightness (or tension) of the balloon increases. The more tightly stretched the balloon, the higher the sound. ACTIVITY EXPLANATION PART II: Drum Building (20 min) 9) Show students an example of a LEGO drum. The model should use a LEGO sturdy triangle as a frame, with a balloon membrane stretched over it and held in place with connector pegs. Point out the pieces used in the model LEGO drum. Remind students that they all built different sturdy triangles, so their drums will not be identical to each others or to the model. Figure 2. Example of LEGO drum with balloon drumhead. STUDENTS INDEPENDENT ACTIVITY 10) Review with students the steps for building their LEGO drums. These steps are listed in their Engineer s Journal. 11) Allow five to ten minutes for initial drum building. After this initial period, ask students to pause in their work so that you may address any common difficulties that students are experiencing. 12) If students finish attaching their balloons earlier than others, suggest that they build a drumstick or a drum stand (or both). Note: If students have trouble making observations, suggest that they explore what happens when they put their ear closer to the drum or when they hold their ear to the table as they tap their drum. PART III: Vibration Observations and Discussion (20 min) 13) When all students have built at least minimally functioning drums, direct students to clean up all LEGO pieces except those on their drums (and drumsticks if relevant), and place their LEGO kits on the floor. Only their drums and journals should remain on their desks. 14) Explain that the class will now work together to investigate how 3-4

27 Science through LEGO Engineering Design a Musical Instrument Lesson 3 How are a sound s vibration size and volume related? Note: Sugar substitute is suggested rather than real sugar because substitute does not leave a sticky residue. It can be brushed off onto the floor and swept up at a later time. For additional assistance, provide each group with a paper plate to place their drum onto. MAKING SENSE OF THE ACTIVITY drums make sounds that our ears can hear. Direct students to play their drums and carefully observe the drums as they play. Can they see or hear any clues that tell them how their drum is making sounds? 15) Ask for a few volunteers to share their observations. Then, acknowledge that it is difficult to observe how the drums make sounds if we use only our eyes and ears. Explain that you will now distribute a material that will make it easier to observe what the drum is doing. 16) Walk around the room and sprinkle a few grains of sugar substitute onto each drum surface. 17) Direct students to play their drums softly and carefully observe them. What happens to the sugar when the drum is played softy? What happens to the sugar when the drum is silent? Students should write and draw any observations on page 3-2 of their Engineer s Journal. 18) Finally, direct students to play their drums hard and observe what happens to the sugar. Students should write and draw any observations on page 3-3 of their Engineer s Journal. 19) Ask for volunteers to share their observations of the sugar-coated drums. 20) Facilitate discussion to help students discover three main ideas: a. When the drum is making sound, the sugar bounces up and down rapidly. This rapid up and down (or back and forth) movement occurs because the drum membrane is also moving up and down. We call this kind of movement vibration. Vibration is required for any sound to happen. In fact, sound is always created by vibrating objects, liquids, or gases. That is, for our ears to hear a sound, some substance must be moving back and forth very rapidly. b. When the drum makes loud sounds, the sugar bounces and spreads around much more than it does when the drum makes quiet sounds. The sugar bounces and spreads more when the drum is loud because loud sound vibrations are BIGGER sound vibrations. The volume of a sound (how loud or quiet it is) depends on the size of its vibrations. The bigger an object s vibrations, the louder its sound. c. The movements of the sugar particles show us that sound is a form of energy, which is the ability to cause change. How do you create bigger vibrations and louder sounds? You must put more effort or force into the vibrating object. To use the scientific term, you must input more energy. Bigger movements are caused by greater amounts of energy. (For example, it takes more gasoline, a type of chemical energy, to move a car 10 miles than it takes to move a car 10 feet.) Because louder sounds are created by bigger vibratory movements, it takes more energy to generate a loud 3-5

28 Science through LEGO Engineering Design a Musical Instrument Lesson 3 How are a sound s vibration size and volume related? sound than to generate a quiet sound. Think about the difference between whispering and yelling. You put more effort, or energy, into yelling than you put into whispering. As a result of your increased energy, the sound vibrations are bigger, and thus the volume of the sound is louder. Larger vibrations " louder volume " more sound energy 3-6

29 Science through LEGO Engineering Lesson 4 What do sound vibrations travel through? Design a Musical Instrument Suggested Time Lesson Overview Learning Objectives Teacher Background One 60-minute session!!!!! This lesson expands on what students learned in Lesson 3 about the importance of vibrations to sound. The focus of the investigation shifts from the source of sound vibrations to the transmitter of sound vibrations. Students will continue to use the LEGO drums built in the previous lesson to explore the transmission of vibrations through air (gases), solids, and liquids. They will also build pan pipes to prepare for the investigation to be conducted in Lesson 5.! Thinking about how sounds travel from instruments to ears! Listening to LEGO drums through solids and liquids! Pan pipe building! Drawing a picture to represent sound travel! Class discussion about the transmission of sound vibrations!!!!! By the end of this lesson, students will be able to: Explain how sound vibrations are transmitted through solid, liquid, and gas mediums.!!!!! For sound to travel from its source to a receiver, such as ears, a medium must be present. Gases (such as air), liquids (such as water), and solids (such as steel) are all mediums that can transmit sounds. Sound is not capable of being transmitted through empty space. For a medium to be a good transmitter of sound, it must be elastic. Elastic substances are able to transmit vibrations without losing much energy to friction or absorbing much energy. Imagine a blob of wet clay and a cube of steel. Your initial judgment might be that the wet clay is more elastic than the steel, in the everyday usage of the word elastic. However, if you put a finger into the clay, the dent does not bounce back. Instead, the clay absorbs the energy of your finger push. In contrast, the steel cube does not seem to be affected by your finger push at all. The steel, then, is more elastic in the scientific usage of the word, and it will transmit sound more quickly and without much loss. Air is also a good transmitter of sound. However, volume decreases more quickly when sound travels through air than through stiff solids. In air, sound moves outward in all directions, while in solids sound travels only in the direction of the solid object. Water is a more efficient transmitter of sound than air because sound travels faster in water. The speed of sound in liquids is faster than the speed of sound in gases, and the speed of sound in solids is faster than the speed of sound in liquids. 4-1

30 Science through LEGO Engineering Design a Musical Instrument Lesson 4 What do sound vibrations travel through? Vocabulary Materials Preparation!!!!! Vibration Rapid and steady back and forth motion. Transmission The process of passing through a space or carrying through a space. Solid The form of matter that has shape and hardness. Liquid The form of matter that can flow easily and takes on the shape of any container into which it is poured. Gas The form of matter that can move about freely, does not have a definite shape, and expands to fill any container in which it is trapped. Medium A substance which carries energy or another substance. Pan Pipe A musical instrument made up of several short pipes of different lengths and played by blowing air across the top. Percussion Instrument Any musical instrument whose vibrations are caused by tapping or hitting. Wind Instrument Any musical instrument whose vibrations are caused by moving air. For each student! Engineer s Journal Part 4! 5 large drinking straws, at least 8 mm in diameter! 12-inch length of Scotch tape or masking tape For each student pair! At least one pair of scissors! LEGO drum from Lesson 3 For the class! Pre-built pan pipe example! Bowl of water deep enough for a sample LEGO drum to fit inside (kept at materials table, not taken to students desks; students will use the water with the teacher)! Paper towels placed next to bowl of water! Stethoscope What Do Children Think about the Transmission of Sound Vibrations? A third-grade student might hold one or more of these beliefs about sound transmission:! Sounds can only travel through air.! When sounds pass through walls or furniture, it is because the walls or furniture actually have many tiny holes in them.! Sounds are emitted from their source directly to people s ears.! Sounds travel from person to person in series.! Sounds can only travel through solids when they are stronger than the solid.!!!!!! Fill large bowl with water! Place bowl, stethoscope, and sample LEGO drum on a separate table or desk.! Build a pan pipe example. 4-2

31 Science through LEGO Engineering Design a Musical Instrument Lesson 4 What do sound vibrations travel through?! Arrange students in pairs.! Distribute Engineer s Journals. Instructions for Teachers GETTING STARTED!!!!! PART I: Introduction and Continued Drum Explorations (15 min) 1) Give students two to three minutes to talk with their partners and then write or draw their ideas about today s exploration question: How does a musical instrument s sound get from the instrument to our ears? Students should record their ideas in their Engineer s Journal. 2) Explain that today is another part of the research phase of the engineering design process for their instrument challenge. Their investigation will focus on the question of how sound travels to our ears. Students will continue to use their LEGO drums and will make a wind instrument called a pan pipe out of drinking straws and tape. 3) Direct students to retrieve their LEGO drums from the previous lesson, but leave all other LEGO pieces in their kits. 4) Ask students: What material does the drum s sound travel through to get from the drum to your ears? Call on student volunteers until a student names air as the material. Help students recognize that the drum s sounds travel through the air that exists between the drum and their ears. What Questions Might Students Ask During this Lesson?! How short should I cut the straws? You may choose any length for each straw as long as you end up with five different lengths.! Why won t my pan pipe make music? You might be blowing air INTO the straw instead of ACROSS it. Pretend that you are blowing out a candle on the other side of the top of the straw. 5) Next, ask students if they think the drum s sound can travel through their desks as well as through the air. Direct students to test their predictions with the following procedure: Place the LEGO drum at one edge of your desk. Press one ear to the desk as far away from the drum as possible. Plug your other ear closed with your hand. Listen carefully through your ear on the desk. Can you hear the drum through the desk? 6) Ask students if a desk is a solid, liquid, or gas material. Help students recognize that desks are solid, and explain that they now have evidence that sound can travel through solids as well as through gases (you might need to remind students that air is a gas). 7) Next, ask students if they think the drum s sound can travel through water as well as through the desk and the air. Explain that students will test their predictions with the following procedure: When your group is called, go to the materials table and place a drum in a large bowl of water. Then place the probe (disk-shaped end) of the 4-3

32 Science through LEGO Engineering Design a Musical Instrument Lesson 4 What do sound vibrations travel through? Note: Students will notice that if they play the drum in the water but hold their ear in the air (rather than up to the stethoscope ear pieces), they will not hear the vibrations from the drum. The drum vibrations make the water vibrate, but the vibrating water does not cause the surrounding air to vibrate. This is because the water vibrations bounce back into the water when they hit the water surface. The vibrations do not cross the water-air barrier. ACTIVITY EXPLANATION Note: This science drawing is actually the focal activity for the concluding class discussion later in the lesson. It is mentioned at this point only so you know it can be used to keep students busy while everyone finishes their pan pipes and their water table visits. stethoscope in the water. Finally, take turns putting the stethoscope ear pieces in your ears and listening for the drum sound. Can you hear the drum through the water? 8) Ask students if water is a solid, liquid, or gas material. Help students recognize that water is liquid, and explain that after they have a chance to listen to their drums through water, they will have evidence that sound can travel through liquids as well as through solids (like their desks) and gases (like air). 9) Explain that you will call student pairs to the testing table while they are working on the next activities, pan pipe building and science drawing. PART II: Sound Vibration Drawing and Pan Pipe Building (25 mins) 10) Before students begin visiting the drum-in-water station, explain the independent work they will do as they wait to be called. 11) The first part of their independent work is today s science drawing assignment. Students should choose one medium solid, liquid, or gas and draw a picture that shows how they think sound travels through that medium on page 4-2 of their Engineer s Journal. 12) Explain that when students finish the drawing assignment, they may begin constructing the pan pipe that will be used in Lesson 5. Figure 1. Straw-and-tape pan pipe. 13) Explain that the pan pipe is an example of a wind instrument, which is any instrument whose vibrations are created by air blowing against a tube. The LEGO drum is a percussion instrument, which is any instrument whose sound is created by tapping or hitting a membrane. 14) Review with students the directions for building pan pipes. These are listed on page 4-3 of their Engineer s Journal. Each student will receive five drinking straws. Their task is to: (1) Cut the straws to five different lengths. (2) Lay the piece of tape on the desk, with its sticky side up. (3) Place the straws on the tape, in order from longest to 4-4