Chapter+5

=Chapter 5: Let us Entertain You= toc

Chapter 5 Section 1

 * What do you Think?**


 * How do violinists and guitarists make different sounds?
 * They strum their instrument in different areas
 * If someone were playing an air guitar, how would the player position his or her fingers to make the highest pitch notes?
 * The closer to the head of the guitar, the higher the pitch of the "guitar" they're playing.


 * Physics Talk**


 * Vibration - the way sound is produced
 * Variables - length and tension
 * Pitch - the quality of the sound on the account of vibrations by the vibrations producing it
 * The more tension strings have = the higher the pitch
 * The farther away you strum, the lower the pitch
 * The shorter the string, the higher the pitch


 * Checking Up**

1. What happens to the pitch of a sound when the tension of the string is increased? 2. When you decrease the length of an instrument, how does the pitch of the sound you hear change? 3. What affect did adding mass to the mass hanger have on the string in the investigate? 4. How is the sound produced on a percussion instrument?
 * The pitch becomes higher
 * The shorter the string, the higher the pitch
 * It made the string have more tension
 * You strike the different blocks and they vibrate to produce a sound


 * Inquiring Further**
 * After reading Evelyn's Essay, it has opened up my mind on what deaf people are actually like. It also amazed me that she is an incredible percussionist. The way she is able to feel the vibrations on her skin is baffling. I am not fully able to grasp that idea, but it sounds very cool. This article made me question if I would be able to play percussion instrument when deaf solely through vibration. How else would you be able to listen if you are playing it right or how it sounds.


 * Physics To Go**

1a. Explain how you can change the tension in a vibrating string 1b. Describe how the change in tension changes the pitch of the sound produced by the string 2a. Explain how you can change the length of a vibrating string on a guitar or violin with your finger during a performance? 2b. How does changing the length change the pitch of the sound produced by the spring? 3a. How could you change the tension of the string, but keep the pitch the same? 3b. How could you change the length of the string and keep the pitch the same? 4. Suppose you change the length and the tension of the string at the same time, what would the result be? 5a. Tell how a performer plays different notes on a guitar that has already been tuned 5b. Tell how a performer or an instrument tuner changes the pitch of the strings to tune a guitar or a piano 6a. What is the purpose of the knobs on a guitar? 6b. Why do you think a guitar needs tuners? 6c. What do you think happens to the pitch as strings stretch due to increase in temperature 7a. What is the purpose of frets in a guitar 7b. Does a violin or cello have frets 7c. Why do violinists and cellists require more finger placement accuracy than a guitarist 8. Design a string instrument that you could use in your sound and light show
 * You can add a mass to the end of it on a pulley, and it will put more tension
 * It stretches out the string and makes the tension more high pitched as opposed to the original sound
 * You can either tune it by tightening the peg, or by pushing back on the string with your finger; thus, increasing the tension
 * Tightening the string will make a higher pitch and loosening the string will make a lower pitch
 * You can change the tension of the string and also change its length and the pitch will remain the same
 * You can also increase the tension so it balances out
 * It would be the same sound as the original because both things cancel each other out
 * They use their fingers to shorten the string theoretically; thus, producing different sounds
 * He changes the pitch of the strings by using the pegs at the end of a guitar or by playing notes on a piano and trying to match them with the guitar
 * The purpose is to tighten or loosen the strings on a guitar
 * Because constant strumming will loosen them to the point where the sound is dull and low pitched all around
 * It becomes low pitched
 * To press the strings against them causing a certain vibration and resulting in a certain pitch
 * No
 * Because they do not have frets to determine where to place their fingers, its more of an experience thing
 * My string instrument would have different strings that are some tight and some loose to produce different pitches.


 * Physics Plus**

f = sqrt(T/4mL)
 * f = frequency
 * t = tension
 * m = mass of string
 * L = length of string

1. Determine by what factor you would have to shorten the string to get a pitch that is double the frequency of the original pitch 2. Determine by what factor you would have to tighten the string to get a pitch double the frequency of the original pitch 3. What would happen if you increase the mass of the string? 4. In a piano, explain why different thicknesses of wires are used in a piano?
 * To double the frequency, multiply the tension by four
 * decrease the length by 1/4, increases the frequency
 * A lower pitch
 * The thicker ones provide a lower, deeper sound whereas the thinner ones provides a higher pitched sound


 * What do you Think Now?**


 * How do violinists and guitarists make different sounds?
 * They tighten and loosen the string on the instrument to produce different pitches. They also place their fingers on the frets to produce different vibrations which make different sounds.
 * If someone were playing an air guitar, how would the player position his or her fingers to make the highest pitch notes?
 * They would position their fingers really close to the head of the guitar because the shorter the string, the higher the pitch of the notes

Chapter 5 Section 2

 * What do you Think Now**


 * How does water move to make a wave?
 * It moves like a sound wave almost, where it has a crest that simmers down when it reaches the shore and all the other characteristics of a wave


 * Physics Talk**


 * wavelength- (lambda) distance from one position of a wave to the same point on another wave
 * frequency- number of waves in a period of time (hertz #waves/second)
 * period - number of seconds it takes to complete one wave (seconds)
 * pulse - a single disturbance, one wave
 * traveling wave - multiple disturbances, constant waves
 * crest- highest point in a wave
 * trough- lowest point in a wave


 * Checking Up**

1. What is a wave? 2. What is the difference between a transverse wave and a longitudinal wave? 3. What is the difference between a node and an antinode?
 * a transfer of energy with no net transfer of mass
 * a transverse wave is a wave in which the direction of the medium moves is perpendicular to the direction of the wave and a longitudinal wave is where the medium is parallel
 * a node is a spot on a standing wave where the medium is motionless and an antinode is a spot on a standing wave where displacement is the largest


 * Physics To Go**

1. Four characteristics of waves are amplitude, wavelength, frequency, and speed 2. Suppose you shake a long, coiled spring slowly back and forth. Then you shake it rapidly 3. Suppose you took a photograph of a periodic wave on a coiled spring. How can you measure the wavelength by looking at the photograph? 4. When you look at the video of a periodic wave going by on a coiled spring, how could you measure the frequency? 5. 6. 7. 8 9  10  11.  12. What is the speed of the wave pulse on the coiled spring 13
 * a. Tell how you measured each one with the coiled spring
 * Amplitude - laid out tape with different lengths (10cm, 20cm, 30cm)
 * Speed - stopwatch
 * b. Give the units used for each
 * amplitude - meters
 * speed - seconds
 * frequency - Hertz (Hz)
 * wavelength - meters
 * c. Which wave characteristics are related to each other? Tell how they are related
 * They are all related except for amplitude
 * c. Which wave characteristics are related to each other? Tell how they are related
 * They are all related except for amplitude
 * a. Describe how the wave changes as you shake it more rapidly
 * There are more waves when you shake it more rapidly
 * b. What wave characteristics change?
 * The frequency increases and the speed increases
 * c. What wave characteristics do not change
 * The wavelength and amplitude remain the same
 * You can measure the distance from one point in a wave to the same exact point in another wave and scale it
 * To find the frequency, you can time it for a period of time, say 10 seconds. In those ten seconds you record how many waves have been completed on the video and divide that number by 10 seconds.
 * a. What are the units of wavelength?
 * meters
 * b) What are the units of frequency?
 * hertz
 * c) What are the units of speed?
 * m/s
 * d) Tell how you find the wave speed from the frequency and the wavelength
 * wavelength divided by frequency
 * e) Use your answer to show how the units of speed are related to the units of wavelength and frequency.
 * speed = m/s ; wavelength (m)/frequency(s)
 * a) What is a standing wave?
 * a wave that remains in a constant position and doesn't move
 * b) Draw a standing wave on a coiled spring. Add labels to your drawing to show how the coiled spring moves.
 * c) Tell how to find the wavelength by observing a standing wave.
 * <span style="font-family: Arial,Helvetica,sans-serif;">a. Explain the differences between transverse and longitudinal waves
 * <span style="font-family: arial,helvetica,sans-serif;">a transverse wave is a wave in which the direction of the medium moves is perpendicular to the direction of the wave and a longitudinal wave is where the medium is parallel
 * b. Coiled Spring waves can be either transverse or compressional. Describe how the coiled-spring moves
 * transverse wave = from side to side, left and right.
 * longitudinal = forward and backwards.
 * a. When you made standing waves, how did you shake the coiled spring to make the wavelength shorter?
 * I did it by shaking the spring more rapidly
 * b. When you made the standing waves, how did you shake the coiled spring to make the wavelength longer?
 * I would shaking the spring slower.
 * a. What are the wavelengths of of each of the wave patterns you have produced?
 * 1 meter, 2 meters, 3 meters, 4 meters, 5 meters
 * b. How are the wave frequencies of the wave patterns related to each other?
 * they are related because the more wave patters that are made, the higher the frequency
 * a. What is the wavelength of the wire wave being produced?
 * 20 meters
 * b. What is the frequency of this wave
 * The period is 2- frequency is reciprocal. The frequency is 1/2 Hz
 * c. What is the speed of the wave
 * speed= d/ t
 * speed= 20/2
 * speed= 10 m/s
 * a. What will the amplitude of the pulse at the moment the centers of each pulse meet
 * 3 meters + 2 meters
 * 5 meters = amplitude
 * b. How would your answer change if the pulses were on opposite sides of the coiled spring?
 * Opposite would happen and you would have to subtract it and end up with an amplitude of 1 meter
 * Speed= m/ s
 * speed= 4.5(2)/2.64
 * Speed= 9/2.64
 * 3.41 m/s
 * a.What is the term for the positions occupied by the clothes
 * The node
 * b. What is the wavelength of the standing wave
 * 6 meters - 3 meters + 3 meters
 * c. What additional wavelengths could exist in the line that the clothes remain stationary
 * It could be 3 or 1.5 because it could be split in half.


 * Physics Plus**

hy


 * What do you Think Now**


 * How does water move to make wave?
 * Wind is the medium. The water travels perpendicular to the medium so it is a transverse wave and the water moves up and down as well so there is an amplitude.

Chapter 5 Section 3

 * What do you Think?**
 * Why does the pitch change when you change the tension of the string?
 * It changes because since the string is tighter/looser, it will create a smaller/larger vibration, resulting in a different pitch


 * Physics To Go**


 * wave speed = wave frequency * wave length
 * decreasing the wave length, increases the frequency and the pitch (Inverse relationship)
 * increasing the wave speed increases the frequency and pitch (direct relationship)


 * Checking Up**

1. How does decreasing the wavelength increase the frequency of the wave? 2. How is the tension of the string related to its pitch 3. Explain how tension relates to wavespeed 4. What is the equation that relates the length of the coiled spring and and the wavelengths of the standing waves that can be produced on the spring?
 * when the wavelength decreases, more waves are able to be completed in a set amount of time (f=v/lambda)
 * an increase in tension produces a larger force, a larger force will produce a greater acceleration on that portion of the string that is displaced and make it vibrate faster
 * The increased mass of the string means that a portion of the string that is displaced to the side will require an increased force to pull it back towards its rest position.
 * L = n(lamda)/2

Chapter 5 Section 4
What do you think?


 * How do flutes and organ pipes produce sound
 * You use the vibration from your voice or by hitting a key and it creates a wave inside the tube

Physics Talk


 * Sound is a compressional wave
 * compresses together then pushes out like a spring.
 * The medium that sound travels through is air.
 * Sound waves travel by moving around barriers.
 * Diffraction - the ability for sound to travel around corners and barriers

Checking Up

1. How does sound travel through air? 2. How do sound waves diffract? 3. How do you express the speed of a wave in terms of its wavelength and its frequency? What is the relationship between wave frequency and wavelength if wave speed remains constant?
 * It travels through air because air is the medium and it uses diffraction
 * They go around corners and barriers by bouncing around and using the air as the medium to travel through
 * The speed of a wave is equal to the product of its frequency and wavelength. If the speed remains the same, the frequency decreases as wavelength increases.

1a. How are these two ways of producing sound? 1b. How are these two ways different 3a. What is the length in meters of the longest organ pipe? 3b. Assume this pipe is closed at one end. Draw the standing wave pattern. 3c. For this pipe, what is the wavelength of this standing wave? 3d. Why does a large wavelength indicate that the frequency will be low, give a reason for your answer
 * PTG**
 * They produce similar sounds by both creating a standing wave.
 * A string has a node at both ends while a tube has an antinode at one end.
 * 11 meters
 * [[image:rosenthal-physicssssss:3tbg3tb3;b3bt.png caption="3tbg3tb3;b3bt.png"]]
 * 44 meters; 1/4 wavelength because it is a closed tube
 * A large wavelength = a lower frequency because if wave speed remains the same, it means that the wavelength increases while frequency decreases.