Ch5_LynchM

=Megan Lynch's Wikilog - Period 8 CP Physics - E. Burns - 2010 =

Section 1
toc How do guitarists or violinists today make different sounds? Changeing the length of the string that is able to vibrate If someone were pretending to play a guitar (for example the air guitar), how would the player position his or her fingers to make the highest pitch notes? Toward the bottom
 * What Do You Think?**

In this image, I see a person strumming a string, and it produces a loud noise. You can tell it is loud because another person's reaction shows him screeching, and his hair blown away by this loud pitch. Also, there is a dog silently strumming a one string guitar.
 * What Do You See?**

Something must vibrate for it to create a sound. Length and tension are the two most important variables of vibration. Placing your fingers on different parts of the guitar neck creates different sounds, because when you shorten the string the there is a higher pitch. Also as tension is increased the pitch increases. To tune an instrument you must either tighten or loosen the strings. For drums, the head of the drum vibrates causes the sound. The length or area of the vibrating surface will have the same effect in the same way as the string.
 * Physics Talk**

1. What happens to the pitch of the sound produced by a string when its tension is increased? The pitch increases. 2. When you decrease the length of a string in an instrument, how does the pitch of the sound you hear change? The pitch increases. 3. What effect did assign mass to the mass hanger have on the string in the Investigate? The tension of the string increased which made the increase the pitch. 4. How is sound produced in a percussion instrument? It is struck on the top creating a vibration.
 * Checking Up**

Doubling frequency requires four times the tension Doubling frequency requires quartering the length If you makes the mass of the string bigger the thinker the pitch and thinner strong makes a higher pitch Changing the length makes to have extremely long unpractical strings so makes the mass more is easier for the piano so stay in shape.
 * Physics Plus**

1. __ a) Explain how you can change the tension in a vibrating string. __ Change the mass by changing the thickness of the string __ b) Describe how changing the tension changes the pitch of the sound produced by the sting __ The more tension the higher the pitch 2. __a) Explain how you can change the length of a vibrating string on a guitar or violin with your finger during a performance.__ Move your finger up or down the neck __b) How does changing the length change the pitch of the sound produced by the string?__ Inverse square relationship 3. __a) How could you change the tension in a string and keep the pitch the same?__ Increase or decrease the length __b) How could you change the length of a string and keep the pitch the same?__ Make the string either thicker or thinner 4. Suppose you change both the length and the tension of the string at the same times. What do you think would happen to the sound? In opposite direction it would change but if they were going to stay the same. 5. __a) Tell how a performer plays different notes on a guitar and on a violin that has been tuned__ Making the string shorter or longer with their fingers __b) Tell how a performer or an instrument tuner changes the pitch of the strings to tune a guitar and to tune a piano__ Change the tension on the string 6. __a) Look at a guitar. Find the tuners (knobs at the end of the neck). What is the purpose of these knobs on a guitar?__ Increase and decrease the tension on the string __b) Why do you think a guitar needs tuners?__ To make it in a lower or higher key of notes __c) Why do violinists and cellists require more finger-placement accuracy in okaying their instruments than a guitarist?__ They have thinner strings 7. __a) What is the purpose of the frets on a guitar?__ Show where on the string the note changes __b) Does a violin or a cello have frets? If you don’t have access to a violin or cello, find some pictures of those instruments.__ No __c) Why do violinists and cellists require more finger-placement accuracy in playing their instruments than a guitarists?__ They don't have frets to guide them.
 * Physics to Go**

How do guitarists or violinists today make different sounds? By increasing/decreasing tension, increasing/decreasing length, or both If someone were pretending to play a guitar (for example, the air guitar, how would the player position his it her fingers to make the highest pitch notes Closest to the bottom
 * What Do You Think Now?**

Section 2
They are riding a spring and in the background and there are waves. Showing there are waves in both.
 * What Do You See?**

How does water move make a wave? The water particles move up and out
 * What Do You Think?**

Frequency is how often a wave passes a point in one second. . A period is how many seconds it takes for one wave to pass. Frequency and period are reciprocals. Wave length is the distance from one point on a wave to the same point on the next wave. The symbol of wave length is l (lambda). Wave speed- is the speed it takes for a wave to travel from one place to another. Amplitude is y-axis and represents the amount of energy of a wave (distance). Traveling wave is regular and repeating pulses. Pulse is a single disturbance in the medium. Crest is the position of maximum amplitude. Trough is a position of minimum amplitude. Transverse wave is one that moves side to side and energy travels perpendicular to the motion of the particle. Longitudinal wave has pulses and has compressions moving down and the energy travels parallel to the particle motion. Medium is the substance that carries the wave. Node is a point on a standing wave where the medium is motionless. Antinode is a point on a standing wave where the displacement is the largest. Wave transfers of energy without a transfer of mass
 * Physics Talk**

1. What is a wave? It is a transfer of energy with no net transfer of mass. 2. What is the difference between a transverse and a longitudinal A transverse wave moves side to side and the energy travels perpendicular to the motion and a longitudinal wave energy travels parallel to the particle motion. 3. What is the difference between a node and an antinode? A node is a point on a standing wave where the medium is motionless. And an antinode is a point on a standing wave where the displacement is the largest.
 * Checking Up**

1. Four characteristics of waves are amplitude, wavelength, frequency, and speed? a) Amplitude is how far you go side to side in meters. Wavelength, you measure the crest and multiply by two because of the trough in meters. Frequency is how often a wave passes a point in one second. Speed is the total distance over the total time measured in m/s. __b) Give the units for each characteristic in your measurment.__ Amplitude is in meters. Wavelength is in meters. Frequency is hertz. Speed is meters per second. __c) Which wave characteristics are related to each other? Tell how they are related.__ Frequency and wavelength are inversely related. Wave speed depends on the medium used. 2. Suppose you shake a long, coiled spring slowly back and forth. Then you shake it rapidly __a) Describe how the waves change as you shake the coiled spring more rapidly__ If frequency increases, wave length decreases. By changing wave speed, you change tension in string. __b) What wave characteristics change?__ Frequency and wavelength. __c) What wave characteristics do not change?__ Wave speed doesn't change. 3. Suppose you took a photograph of a periodic wave ona coiled spring. How can you measure wavelength by looking at the photograph? The wavelength can be measured from one point on one wave to the same point on the next wave. 4. Suppose you mount a video camera on a tripod and aim the camera at one pint on a coiled spring. You also place a clock next to the coiled spring, so the video camera records the time. When you look at the video of a periodic wave going by on the coiled spring, how could you measure the frequency? Frequency is the number of waves over a time of a second. You can see how many waves are passing and divide it by how long the video you recorded. 5. __a) What are the units of wavelength?__ Meters. __b) What are the units of frequency?__ Hertz (Hz) which is the number of waves over time. __c) What are the units of speed?__ Speed is measured in meters/second. __d) Tell how you find the wave speed from the frequency and the wavelength.__ The speed can be measured by wavelength times frequency. __e) Use your answer to show how the units of speed are related to the units of wavelength and frequency.__ Wavelength (meters)*frequency (1/seconds)=meters/seconds (SPEED) 7 __a) Explain the difference between transerse waves and longitudinal waves__ Transverse waves, energy travels perpendicular to the motion of the particle. Longitudinal waves, energy travels parallel to the motion of the particle. __b) Coiled-spring waves can be either transverse or compressional. Describe how the coiled spring moves in each case.__ Transverse waves move from back to forth. Longitudinal waves move in an up and down motion, or compressions moving down. 8. __a) When you made standing waves, how did you shake that coiled spring (change the frequency) to make the wavelength shorter? __ To make wavelength shorter, increase the frequency by shaking the slinky faster. __ b) When you made standing waves, how did you shake the coiled spring (change the frequency) to make the wavelength longer? __ Frequency decreases and the wavelengths increase.  9. A coiled spring is stretched out to 5.0 m in length between you and your partner. By shaking the coiled spring waves with one antinode, two antinodes, three antinodes, four antinodes, and even five antinodes __a)What are the wavelength of each of the wave patterns you have produced?__   __b) How are the frequencies of the wave patterns related to each other__ The greater the frequency, the shorter the wavelength  10. A tightrope walker stands in the middle of a high wire that is stretched 10 m between the two platforms at the ends of the wire . The tightrope walker bounces up and down, creating a standing wave with a single antinode and a periods of 2.0 s. __a) What is the wavelength of the wire wave being produced? __   __b) What is the frequency of the wave?__ The frequency is ½ Hz. <span style="font-family: Arial,Helvetica,sans-serif;"> __c) What is the speed if the wave?__ <span style="font-family: Arial,Helvetica,sans-serif;"> <span style="color: #ff4700; font-family: Arial,Helvetica,sans-serif;"> 11. A transverse pulse with an amplitude of 3 cm is sent to the right along a coiled spring. A second transverse pulse with an amplitude of 2 cm is sent to the left along the same coiled spring and on the same side as the first pulse __<span style="font-family: Arial,Helvetica,sans-serif;">a) What will be the amplitude of the pulse at the moment the centers of each pulse meet? __ <span style="font-family: Arial,Helvetica,sans-serif;">The two waves would add together to make an amplitude of 5 cm. <span style="font-family: Arial,Helvetica,sans-serif;"> __b) How would your answer change if the pulses were on opposite sides of the coiled spring?__ <span style="font-family: Arial,Helvetica,sans-serif;">If they were on opposite sides of the coiled spring, the amplitude would be 1 cm. You get this by subtracting. <span style="color: #ff4700; font-family: Arial,Helvetica,sans-serif;"> 12. During the coiled-spring investigation, your partner generates a wave pulse that takes 2.64 s to go to the far end of the coiled spring and back to your partner. The coiled spring stretches 4.5 m along the floor. What is the speed of the wave pulse on the coiled spring? <span style="font-family: Arial,Helvetica,sans-serif;"> <span style="color: #ff4700; font-family: Arial,Helvetica,sans-serif;"> 13. A clothes line is stretched 9 m between two trees clothes hand on the line as shown in the diagram below. When a particular standing wave is produced in the line by shaking the line, the close remain stationary. __<span style="font-family: Arial,Helvetica,sans-serif;">b) What is the wavelength of this standing wave? __ <span style="font-family: Arial,Helvetica,sans-serif;"> <span style="font-family: Arial,Helvetica,sans-serif;"> __c) What additional wavelengths could exist in the line that the clothes remain stationary?__ <span style="font-family: Arial,Helvetica,sans-serif;">The wavelengths could be 3, 1 and a half, etc when being cut in half.
 * Physics To Go**

a) amplitude - 4m b) period - 5s c) frequency - .2 Hz d) wavelength - 8m e) wavespeed - (8)(.2) = 1.6m/s
 * Physics Plus**
 * Classwork**

Water in the ocean moves to make waves that are both small or powerful. This wave formed is a transverse wave. The water forming the wave has particles that move up and down about the medium. The medium is wind. The wind moves left and right, back and forth. This happens constantly. The water's frequency is high. there are plenty of waves that are created before crashing, reaching the shore.
 * What Do You Think Now?**

Section 3
The man is playing an instrument that looks homemade. It has one string and is made off of a broom stick. The trained lady is playing a stand up bass with many strings. The man's instrument probably doesn't make many pleasant sounds.
 * What Do You See? **

When changing the tension, you are either taking away or adding mass. When adding tension, the pitch becomes higher. When taking away tension, the pitch becomes lower. It changes because tension is a part of vibration.
 * What Do You Think? **

The length of the string is always half the wavelength of the lowest-frequency standing wave. When pitch increases, frequency increases. The equation for wave speed is frequency times wavelength. When length of a string decreases, wavelength also decreases for a standing wave. An inverse relationship is a relationship where decreasing one variable increases the other variable. For example, when decreasing the wavelength, frequency and pitch increase. As frequency increases, the speed of the wave increases. A larger tension force makes a bigger acceleration on that part, creating a fast vibration. In a direct relationship, increasing one variable increases the other variable, and the same for if it decreases.
 * Physics Talk**

**Checking Up** 1. How does decreasing the wavelength increase the frequency of a wave? Explain using an equation that relates the two variables of frequency and wavelength to wave speed. When decreasing the wavelength, frequency and pitch increase. F = v / lambda. If the wavelength gets shorter, the denominator on the right side of the equation gets smaller. the fraction increases, then the left side of the equation gets larger, so the f increases, creating an inverse relationship. 2. How is the tension of a string related to its pitch? The greater the tension, the higher the pitch. If tension decreases, pitch decreases. 3.Explain how tension relates to wave speed. The weaker the tension, the slower the wave speed. 4.What is the equation that relates the length of a coiled spring and the wavelengths of the standing waves that can be produced on the spring? As the tension increases, the pitch increases. This increases the frequency. The speed of the wave gets bigger, and there are more waves that can be carried through, increasing the wave per second. The particles are more tightly joined so as one moves, there isn't as much elasticity between them. When tension increases, the pitch increases. When tension decreases, pitch decreases. The relationship is a direct square root. Adding mass creates more tension. The amplitude decreased as the tension increased.
 * What Do You Think Now?**

Section 4
The people in this image are playing instruments. These instruments are homemade from household products like water pipes and bottles. They are having difficulty making nice sounds from these instruments.
 * What Do You See?**

Flutes and organ pipes make high pitched sounds. The sounds are made from holes. When blowing into the instrument, based upon the whole that is pressed, a different sound will be made.
 * What Do You Think?**

<span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">**<span style="font-family: Arial,Helvetica,sans-serif;">Physics Talk ** <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="font-family: Arial,Helvetica,sans-serif;">Sound is a compressional wave. At the bottom of a test tube there is no vibration and the amplitude (node) is zero so there is no sound. At the open end it is the loudest it can go and the amplitude is at its maximum (antinode). Sound waves travel by moving around barriers. Diffraction is this ability for the waves to be able to bend, spread out and change direction in order to get into an opening. The size of the opening determines the wavelength and volume. If both ends of a tube are open, it forms a vibrating column of air which makes the displacement of the air molecules zero. When one end is closed, the pitch and frequency decrease. If the both ends are open it is 1/2 lambda and double lamba when it is closed.

<span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">**<span style="font-family: Arial,Helvetica,sans-serif;">Checking Up ** <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-decoration: none; vertical-align: baseline;"><span style="color: #008000; font-family: Arial,Helvetica,sans-serif;">1. How does sound travel through air? <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="font-family: Arial,Helvetica,sans-serif;">Sound diffracts. From wave to wave, it can enter and go through different barriers or through different boundaries. <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-decoration: none; vertical-align: baseline;"><span style="color: #008000; font-family: Arial,Helvetica,sans-serif;">2. How do sound waves diffract? <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="font-family: Arial,Helvetica,sans-serif;">By bending. They find openings. They change direction (and magnitude) in order to get through different sized barriers or doorways. <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-decoration: none; vertical-align: baseline;"><span style="color: #008000; font-family: Arial,Helvetica,sans-serif;">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? <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="font-family: Arial,Helvetica,sans-serif;">The speed can be determined by multiplying the wavelength and the frequency. If the wave speed is constant than the frequency and wavelength are also constant. <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">**<span style="font-family: Arial,Helvetica,sans-serif;">Physics To Go ** <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-decoration: none; vertical-align: baseline;"><span style="color: #008000; font-family: Arial,Helvetica,sans-serif;">1. You can produce a sound by plucking a string or by blowing into a pope. <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">__<span style="font-family: Arial,Helvetica,sans-serif;">a) How are these two ways of producing similar sound? __ <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="font-family: Arial,Helvetica,sans-serif;">Produced by standing waves and they're an octave apart. <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">__<span style="font-family: Arial,Helvetica,sans-serif;">b) How are these two ways different? __ <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="font-family: Arial,Helvetica,sans-serif;">Shortening the string or tube makes the frequency higher. In a string, there are nodes at both ends. In a closed tube, there is a node at one and an anti node at the other. <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-decoration: none; vertical-align: baseline;"><span style="color: #008000; font-family: Arial,Helvetica,sans-serif;">3. Find some information on the length of organ pipes <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">__<span style="font-family: Arial,Helvetica,sans-serif;">a) What is the length, in meters, of the longest organ pipe? __ <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="font-family: Arial,Helvetica,sans-serif;">11 meters <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">__<span style="font-family: Arial,Helvetica,sans-serif;">b) Assume this pipe is closed at one end. Draw the standing wave pattern.<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"> __ <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">__<span style="font-family: Arial,Helvetica,sans-serif;"> c) For this pipe, what is the wavelength of this standing wave? __ <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="font-family: Arial,Helvetica,sans-serif;">The wavelength is 44 meters. It is a closed tube which includes the 1/4. <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">__<span style="font-family: Arial,Helvetica,sans-serif;">d) Why does a large wavelength of this standing wave? __ <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="font-family: Arial,Helvetica,sans-serif;">The two are indirectly related. Speed must remain constant. As wavelength increases, frequency decreases and visa versa. <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-decoration: none; vertical-align: baseline;"><span style="color: #008000; font-family: Arial,Helvetica,sans-serif;">4. Suppose you are listening to the sound of an organ pipe that is closed <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">__<span style="font-family: Arial,Helvetica,sans-serif;">a) What is the wavelength of the sound in the pipe? __ <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="font-family: Arial,Helvetica,sans-serif;">12 meters <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">__<span style="font-family: Arial,Helvetica,sans-serif;">b) The speed of sound in air is about 340 m/s. What is the frequency of the sound wave? __ <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="font-family: Arial,Helvetica,sans-serif;"> <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">__<span style="font-family: Arial,Helvetica,sans-serif;">c) Now suppose you are listening to the sound of an organ pipe that is open at both ends. As before, the pipe is 3 m long. What is the wavelength of the sound in the pipe? __ <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="font-family: Arial,Helvetica,sans-serif;">6 meters <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">__<span style="font-family: Arial,Helvetica,sans-serif;">d) What is the frequency of the sound wave __ <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="font-family: Arial,Helvetica,sans-serif;"> <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-decoration: none; vertical-align: baseline;"><span style="color: #008000; font-family: Arial,Helvetica,sans-serif;">5. Suppose you listen to the sound of an organ that is closed at one end. This pipe is 1 m long. How does its frequency compare with the frequency you found in Question 4.b) <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="font-family: Arial,Helvetica,sans-serif;">A shorter pipe has a much higher frequency. This is three times greater.  <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-decoration: none; vertical-align: baseline;"><span style="color: #008000; font-family: Arial,Helvetica,sans-serif;">6. What is the wave phenomenon called?  <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">__<span style="font-family: Arial,Helvetica,sans-serif;">a) Diffraction __ <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;">__<span style="font-family: Arial,Helvetica,sans-serif;">b) Draw a diagram to illustrate this phenomenon. __ <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-decoration: none; vertical-align: baseline;"><span style="color: #008000; font-family: Arial,Helvetica,sans-serif;">7. A drum corps can be heard practicing at a distance of 1.6 km (about 1 mile0 from the field. What is the delay between the drumstick hitting the drum and the sound heard by an individual 1.6 km away? (Assume the speed of sound in air be 340 m/s) <span style="background-color: transparent; color: #000000; font-family: serif; font-size: 16px; text-align: start; text-decoration: none; vertical-align: baseline;"><span style="font-family: Arial,Helvetica,sans-serif;">