The Science of Sound (Native American Acoustics)

Transcription

1 The Science of Sound (Native American Acoustics)

2 Background Why is this topic important to the communities? This unit is designed to enrich students' understanding and appreciation of Aboriginal science and technology related to the sound and modern acoustics and to encourage students to continue their studies in the field of physical science in the future. Native American communities in different areas of north America were successful at different types of innovations.some communities were excellent tool makers, while other had a talent for creating forms of transportations.some groups were especially good at farming and harvesting crops but nearly all of them show a great creativity toward creating musical instruments that produced sounds that may kept their feeling of harmony with the nature and environment around them. Native American sound& acoustics world are rich with many great musical inventions that are used for multiple of purposes and we are going through this Unit to shed only lights on some of them A Brief overview on Native American Contributions and inventions related to sound and musical instruments Indian hunter s throughout Americas used sound to make animals calls. They designed their sound tools and instruments to make calls similar to those made by the animals that they wanted to hunt. As an example to attract a female deer, hunter placed blades of grass between their thumbs and blew over it to make a sound like that of a fawn (fawn: A young deer in its first year). When the hunter blew over the grass it vibrates creating a fawn sound. To change the sound, the hunter have to tightened or loosened the blade of glass, This changed the frequency of the sound waves and so creating different high or low pitched sound (Frequency: Is the number of vibration air molecule do per second)

3 Inuit hunters of the arctic put a pick in to the ice and whistled along the shaft to coax a seal or walrus back to a breathing hole it had made in the ice.this vibration that this made sounded like the noises that seals make American Indian also used other way to create animals sound like the sound of two stags (male deer) made by banging antlers together to call the animal, also people of the great basin banged stick or rocks together to imitate the sound of sheep and butting heads Creating animal sounds though different methods for hunting purposes seem to be something essential for their survival Native American also has invented a number of percussion and wind instruments. Percussion instruments such as drums and bells they only produce sound once they are struck. Wind instruments such as flutes and horns which vibrates when a musician blows through them.we will get to introduce some of these instruments and their uses to show how great did the native American utilizes different materials from the environment around them in creating such creative musical instruments which lead to development of a lot of modern musical instruments known now a days

4 1-Drums Many groups of North American Indians made drums by stretching hide (animal skin) over a wooden frame. The controlled the sound pitch of the drum by how tightly the stretched hide. (Sound pitch is how high or low the sound will be) The more tightly they stretched the hide, the higher the drum sound will be.most American Indian musician stretched a hide over only one end of the wooden frame Here are different types of drums made by different Native American tribes Pueblo people of the southwest made drums by stretching hide over both ends of a hallowed log. The Iroquois people of northeast made music with barrel shaped drums that they carved from wood.iroquois musician s also poured water into their drums before covering the tops with hide. Iroquois musician also played the tambourine (a small drum that is held in the hand) and a double headed drum

5 Aztec musician of Mesoamerica (Now Mexico) used different kind of drum which has a barrels shape called teponazlti, this drum had five tongues that vibrated at different rates when a player struck them with a rubber tripped mallets. Each tongue produce a different sound 2-Rattles: Indian throughout the Americas made rattles, hallow instruments that contained dried seeds or pebbles (Tiny rocks).when a musician shook the rattle, seeds or pebbles struck against the container and made it vibrate. American Indian made rattles from turtles, shells, gourds or large cocoons filled pebbles.the also made rattles from deer hooves, Also American Indian of the northwest made rattles from wood which was plentiful where they live. 3- Hunting bows: Indian of the plateau regions and the great basin played music on the bows that they used for hunting. They made bow strings from a piece of sinew, the tough fiber that holds an animal s muscle to its bone. They tied this string to each end of a strong and flexible piece of wood so that the wood is curved or bowed.to play the music one has to create a vibration in the string so the player held the string of the bow in his teeth and struck it with a stick, changing the shape of his mouth to change the sound.

6 4- Flutes: Flutes are from a single hallow tube. They are played by blowing in air over one end of the tube.flutes have fingers holes along the side.by covering and un covering different finger holes, a flute players can make different notes. In North America, Indian of the plateau, northeast, southwest and the great plains cultures made wooden flutes.they played flute music to entertain people.young men played love songs on the flute to impress young women that they wanted to marry. The Sioux Indian (Dakota, Lakota and Nakota) made cedar flutes with five holes that could play five notes Summary It is quite obvious how Native American have been leaders in the world of sound and music. Drum, rattles, bells, whistles, horns, panpipes and flutes are all musical instruments developed by native American moreover than sound techniques used in animal calls like Deer, Elk, moose, sheep, seal, walrus and caribou calls, each animal call native American have developed the required technique to call it so that it could be easily hunted. All these different instruments and techniques were made by different materials in their surrounding environment, Wood, plants, animal skins and seeds and others are all natural raw materials used by Native American to make use of air vibrations in creating different sounds with different pitches. A lot of these musical instruments developed by ancient Native Americans are still used up till now by their offspring and some others have been developed to new modern ones which have the same sound creation basic

7 How does it connect to science big science? Sound is invisible waves moving through the air around us. In the same way that ocean waves are made of ocean water, sound waves are made of the air (or water or whatever) they are moving through. When something vibrates, it disturbs the air molecules around it. The disturbance moves through the air in waves - each vibration making its own wave in the air -spreading out from the thing that made the sound, just as water waves spread out from a stone that's been dropped into a pond. You can see a short animation of a noise being created here. Surf rolling down a beach, leaves rustling in the wind, a book thudding on a desk, or a plate crashing on the all make sounds, but these sounds are not music. Music is sound that's organized by people on purpose, to dance to, to tell a story, to make other people feel a certain way, or just to sound pretty or be entertaining. So generally Sound is a type of energy made by vibrations. When any object vibrates, it causes movement in the air particles. These particles bump into the particles close to them, which makes them vibrate too causing them to bump into more air particles. This movement, called sound waves, keeps going until they run out of energy. Sounds reach our ears by the air being vibrated. The Air is being squashed and stretched to make sound waves. When this sound waves travel through the air the vibrations reach our ears and they make our eardrums vibrate, this then sends a message to our brain and the brain hears the sound Waves as a general term are disturbances; they are changes in something - the Surface of the ocean, the air, electromagnetic Fields. Normally, these changes are travelling (except for Standing Waves); the disturbance is moving away from whatever created it. Most kinds of waves are transverse waves. In a transverse wave, as the wave is moving in one direction, it is creating a disturbance in a different direction. The most familiar example of this is waves on the surface of water. As the wave travels in one direction - say south - it is creating an up-and-down (not north-and south) Motion on the water's surface this kind of wave is very easy to draw; a line going from left-to-right has upand-down wiggles Sound waves are not transverse. Sound waves are longitudinal waves. If sound waves are moving south, the disturbance that they are creating is making the air molecules vibrate north-and-south (not east-and-west, or up-and-down. This is very difficult to show clearly in a diagram, so most diagrams, even diagrams of sound waves, show transverse waves.

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9 Some important Terms and Concepts Sound Waves - When something vibrates, it makes a sound. The vibrations travel out in all directions from the "something" in the same way that ripples travel out from a pebble that has been dropped in water. But instead of being waves of water, these are waves of vibrations of air: sound waves. Because it is the air itself that is vibrating, sound waves, unlike water waves, are invisible. Frequency - or Pitch - Think of water waves again. They can be close together or far apart. If they are close together, there are more of them; they are more frequent. Frequency is the term that scientists and engineers use to describe how many pulses of a sound wave arrive at your ear in one second. Musicians use the term pitch. A sound with a higher frequency (more waves) has a higher pitch, and sounds higher. Amplitude - or Dynamic Level - Water waves can also be great, big, tall waves, or small ripples. The size of a wave is called its amplitude. In sound waves, the bigger the wave, the louder the sound is. Musicians call the loudness of a sound its dynamic level. Frequency, Wavelength, and Pitch Any sound that you hear as a tone is made of regular, evenly spaced waves of air molecules. The most noticeable difference between various tonal sounds is that some sound higher or lower than others. These differences in the pitch of the sound are caused by different spacing in the waves; the closer together the waves are, the higher the tone sounds. The spacing of the waves - the distance from the high point of one wave to the next one - is the wavelength All sound waves are travelling at about the same speed - the speed of sound. So waves with a longer wavelength don't arrive (at your ear, for example) as often (frequently) as the shorter waves. This aspect of a sound - how often a wave peak goes by, is called frequency by scientists and engineers. They measure it in hertz, which is how many wave peaks go by in one second. People can hear sounds that range from about 20 to about 17,000 hertz. The word that musicians use for frequency is pitch. The shorter the wavelength, the higher the frequency, and the higher the pitch of the sound. In other words, short waves sound high; long waves sound low.

10 How does it connect to science grade level subject foci? Curriculum connect: Grade 4: Physical science :Sound (SO) SO4.1 Explore natural and artificial sources of sound in the environment and how those sounds are detected by humans and animals SO4.2 Draw conclusions about the characteristics and physical properties of sound, including pitch and loudness, based on observation How does it link to student interests? Student interested music art, sound production and various musical instrument will find this unit useful as it give a historical background on the development of first nation musical instrument, its developments and uses.also it enhance the student knowledge about some basic concepts related to sound wave, travelling and properties

11 Activity 1: How to make Drum sound louder Difficulty Level: 1 (Simple) Period: One class Learning outcome (Objective) : Student will learn about Drums as a percussion instrument sounded by being struck with sticks or the hands sounds are produces due to air vibration inside the drum frame, this activity is to post questions on how drums produce sounds and how could students modify drum to produce louder sounds Activity Preparation: This activity is based on the previous overview of American Contributions and inventions related the sound and musical instruments The historical overview American Contributions and inventions related the sound and musical instruments Previously presented should be firstly introduced to the student by one of the following methods: 1-Direct instruction accompanied by the use of some posters and pictures for the different types of musical instruments used by Native American (these posters should be specially prepared to present only the Native American different musical instruments and their names and functions) 2-Interactive instructions: This should be made by allowing the students to watch a video (20min- 30min) about the same topic presented previously (mainly about Native American contributions and inventions related to sound or Native American musical instruments) **I do recommend the production of 20 Minuit video that explain the different types of musical instruments used by native American, showing the sound produced by each instrument, how the instrument are developed from one tribes to anther and end with a 5 min play of any indigenous musical band Please refer to the following video links for similar examples: o o Instructions (Activity step by step): Teachers should make an open discussion with the students based on the information they learned from the previous history of native American with musical instruments Some Questions to guide student reflection and learning: 1. What possible ways to increase the sound of a drum which is stretched from one end? Ans: hitting the drum harder Increase the tightness of the material covering drum top surface 2. Why drums made by the pueblo people (Both end stretched with hide) produces higher sound? Ans: sound waves bounces back and forth inside the walls of the hallow space inside a double sided closed drum so it become amplified producing louder sounds 3. Why do you think the Iroquois musicians poured water in their drums? Ans: The pitch produced by the drum can be changed depending on how wet is the skin top of the drum also water give echoing sound that can be heard for long distances

12 4. What will happen to the sound of the drum if I used rubber, wood or cupboard instead of the hide used by the Native American? Ans: the material used on the top and bottom sides of the drum greatly affect the sound produced from it, so changing the top and bottom sides from hide (animal skin) to any other different material will led to producing of different sounds with different pitches 5. Why it is better to have a hallow frame for the drum rather than a Complete solid frame made of wood? Ans: This question may have different answers one is that hollow drums have less weight so that make it easier to use and handle, a second reason may be that sound travel faster in solids than in air due to high dense of soiled molecule which increase the speed of propagation through this may make the sound produce by the drum un distinguishable for the human ears Notes for teachers: It is important to introduce such questions or similar ones on the students in their first class and leave them to thinking in it till the make the next activity Activity 2: How to make your own drum Difficulty Level: 1 (Simple) Period: one class Learning Outcomes (Objective): This activity is to learn kids how to made their own musical instruments drum with simple materials and tools Student will also learn how sound is produce due vibration of air molecules Understanding basics terms like sound frequency and wave length Enhance the student skills in make simple scientific hand-on crafts Materials: 1. Oatmeal canister or large juice or coffee cans or other container that is drum-shaped 2. Wax paper 3. Colored thick cardboard or papers 4. 2 rubber balloons 5. Large rubber bands 6. Construction paper 7. Glitter(optional) 8. Markers or colors 9. Clear-drying craft glue 10. Scissors 11. Two unsharpened pencils or chopsticks Instructions (Activity step by step): The class should be divided in to three groups, one group is to use wax paper as the drum surface, the second is to use the rubber balloon and the last is to used thick colored cardboards 1. Choose a cylindrical oatmeal container, large juice or coffee can, or other container that is drum-shaped. Juice containers and coffee cans should be open on one side, and sharp edges should be covered with masking tape or filed down. Take the lid off the oatmeal container and discard it. This container will form the base for the drums 2. Cut the colored cardboard or paper into equal size strips which are the container's height these will be used later for the drum's decoration.

13 3. Decorate your drum by gluing the strips around the outside of your container and leave it to dry. 4. Cut a circle of waxed paper or the thick colored cardboard that is relatively larger in diameter than the open end of the container or can. This material will form the surface of the drum that is beaten with the sticks.for the group using the balloon cut off the narrow part of the balloon 5. Stretch the waxed paper or the thick colored cardboard or balloon and hold it down tightly with the large rubber band. Make sure the top is tight across the opening without any wrinkles or creases 6. Cut out a piece of construction paper in a size needed to cover the entire outside of the cylinder drum shape. You can measure this out easily by rolling the cylinder on the piece of paper and marking the edges with a pencil 7. Decorate one side of the construction paper drum covering with more colored paper, sequins, trims, narrow cords, yarn, glitter, or any other attractive embellishment your students prefer. 8. Glue the completed paper drum covering to the outside of the drum. Be sure to glue securely over the rubber band and edge of the waxed paper drumming surface. Allow the drum to dry completely before playing 9. Two unsharpened pencils make excellent drum sticks, although you can use chopsticks or other small sticks. 10. Each group is asked to test their drum separately and listen carefully to the sound produced from it. Each group should be able to identify the different sound produced by the drums of other groups Questions to guide student reflection and learning (Activity discussion): Teachers are to discuss with the students some of the following observations that will answer to them some of the questions proposed in the previous activity o o o o o o Does the Material that cover the top of the drum affect the sound produced by it? Which produce louder sound the waxed paper drum, cardboard or the rubber balloon? What my happen if we used a longer oatmeal container, or bigger size one?does that affect the sound produced? What if we want to make mixed sound using this simple drum, try to put in your drum some small amount of rice, beans or may be dust and see how that affect the sound produced? Hitting the drum harder will increase the sound produce from it as it increase the vibrations of air inside the drum hallow space and so increasing the amplitude of sound Double sided drum produce louder sound than drum covered only from one side as the sound waves bounces back and forth inside the walls of the hallow space inside a drum it become amplified producing louder sounds Other Useful links & videos for the activity

14 Activity 3: Water Whistle Difficulty Level: 1 (Simple) Period: one class Learning Outcome (Objective): This activity is to teach kids how to make a very simple musical instruments out of nothing more than a drinking straw and a glass of water. Its musical and fun as well as a great lesson in vibration, sound, and pitch. Material s: Drinking straw Pair of scissors Cup or glass Water Instructions: 1. Using your scissors, cut partially through the straw 1/3 of the way down the straw. The cut should be ALMOST all the way through the straw but leave a small piece uncut to keep the two straw sections attached. 2. Bend the straw into a right angle at the cut being careful not to break the straw segments clean of each other. 3. Fill a cup or glass 3/4 full with water. 4. Slide the longer section of straw into the water. 5. Keeping the straw at a 90 degree angle, place your lips on the shorter end of the straw and blow with a light, constant breath. What do you hear? 6. Once you've got your Water Whistle making a constant, steady sound, trying raising or lowering the straw within the water. Questions to guide student reflection and learning (Activity discussion): Teachers are to discuss with the students some of the following observations What happens to the pitch of your Water Whistle when they raise and lower the straw within the water? What if we filled only quarter or half the cup with water? Where are our sound waves traveling, Is it through the air or the water? What is the effect of different types of straws out? What happens if you use a wider straw? A thinner straw? Try different liquids. Does the pitch change in soda or milk? Scientific methods: Water Whistle actual works through the vibration of air itself and, more specifically, the column of air inside the straw. The longer segment of straw that you have partially submerged in water is full of air and water (the amount of each depends on how deep you have your straw in the water). When you blow the air across the top of the longer straw segment, you are causing the column of air to vibrate. This vibrating column of air creates the whistling sound you hear. The pitch of the whistling is dependent on how much air you allow to be inside the straw. The more air that is inside of the straw, the lower the pitch of the whistle less air is going to create a higher pitch. Other Useful links & videos for the activity

15 Activity 4: water bottles Xylophone Difficulty Level: 2 (medium) Period: one class Learning Outcome (Objective): This activity is to demonstrate the different between different sound pitches by creating a water musical instrument which can play real music Material s: 5 identical glass bottles. These could be thin jars, beakers, or even empty glass soda bottles. Water Food coloring A spoon or fork Instructions: 1. Place the bottles in a straight line, about 2 to 4 inches apart from each other. 2. Fill the bottles one-by-one until the water level is staggered. For example, fill the first bottle with a small amount of water. Fill the second bottle with more water than the first bottle. Fill the third bottle with more water than the second bottle, and so forth and so on until all of your bottles have a varying amount of water. When you re done the first bottle should have the least amount of water and the last bottle the most. 3. Give water in each bottle a color to differentiate between different bottle and that by simply using food coloring so that we have 5 different colored water 4. Take your spoon, fork and strike the tops of each bottle one after the other and listen to the different pitches. 5. Strike the bottles in any order to make music. 6. Repeat the same experiment steps but instead of striking the bottles with a spoon blow across the top with your mouth to get a tone Questions to guide student reflection and learning (Activity discussion): Teachers are to discuss with the students some of the following observations Which bottles produces higher pitch when we strike it with the spoon? What kind of mediums the sound waves travel through in this experiment? In case of blowing across the bottle top which bottle will give higher pitch in this case? Can we play a real tune on our water musical bottles? Frequency of sound (Pitch) is related to how quickly the sound wave can make a round trip through the thing it s traveling through. So when striking the top of the bottles the fewer water bottles, it takes less time for it to make the round trip, and the pitch goes up Moreover as you add water it takes on greater vibrating mass. The less water that's in the bottle means there is less weight that vibrates and the pitch is higher. While in case of blowing across the top of the bottles the bottle with less water will now have a lower pitch. That s because now the sound is traveling through the air in the bottle. The more air, the more time it takes the sound wave to do the round trip, so the lower the pitch. Other Useful links & videos for the activity

16 For a more detailed background about the science or sound and music and comprehensive list of activities that enhance student understanding for sound wave propagation and related physical term please refer to the following references Sound, Physics and Music, By: Catherine Schmidt-Jones For Useful activity please refer to the following sub-section: , , , Also check the following section for more background and information: 1.1, 1.2, 1.3, 1.4, 1.5, 3.1) Animal sounds Some Teacher resources