Ch_5BranchiniB

Chapter 5, Section 1
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 * What do you think?**
 * Guitarists are able to produce different sounds due to the positioning of their fingers. Whenever the string tighter, there is a higher pitch. One would move the strum closest to the strumming finger in order to produce the highest pitch.


 * Physics Talk**
 * In order to produce sound, there must be vibration
 * The two components of sound include tension and length
 * Vibrate: to move back and forth rapidly
 * Variable: something that can change or vary during an investigation
 * Pitch: how high or low a note is
 * The pitch is higher when the string is shorter
 * When you increase tension, you are also making a higher pitch

1. As the tension increases, the pitch also increases 2. As the length of the string decreases, the pitch increases 3. As mass is added, the tension is increased, hence, the pitch becomes higher 4. It is produced by striking the instrument to cause a vibration
 * Checking Up**

http://www.evelyn.co.uk/biography.aspx Dame Evelyn is very special precussionist. She uses touch as a specialized form of hearing. Someone who is deaf can feel sounds. As the frequency gets higher, they feel the vibrations. Dame was able to give notes by means of her body feeling the vibration. The low sounds were felt in her legs and feet and high sounds felt in the face, neck and chest, she can also can see items move and vibrate. These forms of hearing are complex and we use this form by we call it listening.
 * Inquiring Further**

1. To get the frequency doubled, you would multiply the tension by four. This is a squared relationship. 2. To get the frequency doubled, you must get 1/4 the length of the string. This is an inverse squared relationship. 3. As the mass of the vibrating string increases, the frequency would be lowered. This is an inverse squared relationship. 4. The thick wires have a lower pitched sound and the thin wires have a higher pitched sound.
 * Physics Plus**
 * F = sqrt (T/4mL) where f = frequency ; T = tension ; m = mass of string ; L = length of string**

1. a) By adding mass to the string, you change the tension. b) Whenever you change the tension, you change the pitch of the sound. Whenever there is more tension, there is a higher pitch. 2. a) You can change the length of the string by pressing your finger down on the string on different frets. b) Whenever you change the length of the string, you change the pitch. Whenever you decrease the length, there is a higher pitch. 3. a) You can change the tension of the string and keep the pitch the same when adjusting the tuners on the guitar. b) You can change the length of the string and keep the pitch the same when moving your fingers on different frets. 4. If you change both the length of the string and the tension the sound would change depending on which one you change. If you increased the tension and you decrease the length the length of the string, you will get a higher pitch. 5. a) A guitarist changes the position of his fingers to play different notes. This would change the length of the string. b) An instrument tuner changes the pitches of the string when tightening or loosening the strings. This changes the tension of the string. 6. a) These knobs keep the string attached to the guitar. It also changes the amount of tension, changing the pitch. b) A guitar needs a tuner because at times, you need to change the sound of the pitch; from low or high. c) When the strings stretch out, the pitch gets lower, due to an increase in length of the string. 7. a) Frets change the length of the string. The different pitches depend on which fret you press. b) Violins and Cellos both do not have frets. c) They are more difficult to play because you must be more accurate with where you press your finger. There are no frets to let you know where your finger needs to be placed. 8. If I were to do a guitar and light show, I would want an instrument with high pitches due to the loudness of the concert. To make these high pitches, I would make the guitar have strings with great tension and short in length.
 * Physics To Go**


 * What do you think now?**
 * Guitarists and violinists make different sounds when they change the pitch. The two factors of pitch change include the amount of tension and the length of the string. To make the pitch higher, you would increase the amount of tension (tighten strings) and you would decrease the length of the string (fret placement). If you were to air guitar, you would place your fingers lower on the neck of the guitar to make the higher pitch.

Chapter 5, Section 2

 * What do you think?**
 * Water moves to make a wave by the water rising and falling down to make a parabola shaped wave. The top of the wave is moves much faster than the bottom of the wave so it crashes down.


 * Physics Talk**
 * Wave: a transfer of energy with no net transfer of mass
 * Medium: the material through which a wave can travel
 * Periodic wave: a repetitive series of pulses; a wave sequence in which the particles of the medium undergo periodic motion: after a fixed amount of time, the medium returns to its starting point and then repeats its oscillation
 * Crest: the highest point of displacement of a wave
 * Trough: the lowest point of displacement of a wave
 * Amplitude: the maximum displacement of a particle as a wave passes; the highest of a wave crest
 * Wavelength: the distance between two identical points in consecutive cycles of a wave
 * Frequency: the number of waves produced per unit time; the reciprocal of the amount of time it takes for a single wavelength to pass a point
 * Period: the time required to complete one cycle of a wave
 * Transverse wave: a wave in which the motion of the medium is perpendicular to the motion of the wave
 * Longitudinal wave: a wave in which the motion of the medium is parallel to the direction of the motion of the wave
 * Standing wave: a wave pattern that remains in a constant position
 * Node: a point on a standing wave where the medium is motionless
 * Antinode: a point on a standing wave where the displacement is the largest

1. A wave is a transfer of energy with no net transfer of mass. 2. A transverse wave is a wave in which the motion of the medium is perpendicular to the motion of the wave, while a longitudinal wave is a wave in which the motion of the medium is parallel to the direction of the motion of the wave. 3. A node is a point on a standing wave where the medium is motionless, while an antinode is a point on a standing wave where the displacement is the largest.
 * Checking Up**

c) Frequency and wavelength are inversely related. Amplitude has no effect on anything, as it is not related to one characteristic. Wave speed is dependent upon the medium. 2. a) The frequency would increase, while the wave length would decrease. b) The wavelength and the frequency would both change. c) The amplitude and the wave speed do not change. 3. You can measure the wavelength by taking the distance between one point on a wave to same point on a different wave. 4. You can measure the frequency by seeing the number of waves and dividing it by the time you recorded. 5. a) The units for wavelength are meters. b) The units for frequency are hertz. c) The units for wave speed are m/s. d) You would multiply the wavelength and the frequency to obtain your speed. e) Wavelength (m) x Frequency (1/s) = Wave speed (m/s) 6. a) A standing wave is a wave pattern that remains in a constant position. b) c) You find the wavelength by finding the distance from a crest to a trough. 7. a) Transverse waves have energy that travels perpendicular to the motion of the particle, while longitudinal waves have energy that travels parallel to the motion of the particle. b) Transverse waves tend to always move back and forth. Longitudinal waves tend to always move up and down. 8. a) In order to make the wave length shorter, you would increase the frequency. b) In order to make the wave length longer, you would decrease the frequency. 9. a) (n) (1/2) (wavelength) = L 5 x .5 x wavelength = 5  = 2 m
 * Physics To Go**
 * 1. a) We measured the amplitude by determining the highest of the wave crest and the maximum displacement of the wave. We measured wavelengths by determining the distance between two identical points (measuring the displacement). We measured frequency by determining the number of waves produced per unit time or the amount of times the hands went back and forth. We measured speed by determining the total distance and dividing it by the total time. **
 * b) The units for amplitude are meters. The units for wavelength are meters. The units for frequency are hertz. The unites for wave speed are m/s. **

4 x .5 x wavelength = 5 = 2.5 m

3 x .5 x wavelength = 5 = 3.33 m

2 x .5 x wavelength = 5 = 5 m

1 x .5 x wavelength = 5 = 1 m b) Whenever the frequency is greater, the wave length must be shorter.

10. a) (n) (1/2) (wavelength) = L 1 x .5 x wavelength = 10  = 20 m

b) The frequency of the wave is 0.5 Hz. c) wave speed = f x lambda =.5 x 20 = 10 m/s

11. a) The amplitude would be 5 cm, after adding two waves together. b) The amplitude would then be 1 cm. This is because you would subtract both waves.

12. speed = distance / time = 9 / 2.64 = 3.41m/s

13. a) The clothes are the nodes and the space between are the anti-nodes. b) (n) (1/2) (wavelength) = L  3 x 1.5 x wavelength = 9 = 6 m

c) The wavelengths could be either 3 or 1.5 when splitting it in half.

**Physics Plus**




 * What do you think now?**
 * In the ocean, water tends to make very strong waves or very small waves. A wave found in a water is known as a transverse wave. The water that forms the wave has particles that move up and down. It is dependent upon the medium, which is the wind. Constantly, the wind moves horizontally (left to right) and vertically (up and down). Water has a very high frequency.

Chapter 5, Section 3

 * What do you think?**
 * You take away the mass or you are adding the mass. The pitch is higher when you add more tension. When you lower the tension, the pitch becomes lower. Tension is one of the main components of vibration.


 * Physics Talk**
 * ** Pitch and frequency have a direct relationship, thus if pitch increases, so will frequency. **
 * ** The length of the string is always half the wavelength of the lowest-frequency standing wave. **
 * ** Wave Speed = Frequency x Wavelength **
 * ** For standing waves, when the wave length decreases, the length of the string must have been decreased, as well. **
 * ** An inverse relationship: A relationship where decreasing one variable increases the other variable **
 * ** When you decrease the wavelength, the pitch and frequency must increase. **
 * ** Speed of the wave and the frequency have a direct relationship, thus if the speed increases, so does the frequency. **
 * ** A bigger tension would create a fast vibration **
 * ** L = (n) x (lambda) / 2 **

1. When you decrease the wavelength, the pitch and frequency increases. This is because they have an inverse relationship. 2. If the tension is greater, the higher the pitch is. If the tension is lower, the lower the pitch is. 3. If the tension is weak, the wave speed must be slower. 4. ** L = (n) x (lambda) / 2 **
 * Checking Up**


 * What do you think now?**
 * When tension increases, the pitch and frequency both increase. The waves per second is increased. This causes the string to vibrate more. There is an increase in acceleration when the string vibrates more. This creates the higher wave speed. The relationship between wave speed and frequency is a direct relationship. Thus, if you increase the wave speed, you increase the frequency.

Chapter 5, Section 4

 * What do you think?**
 * They make high-pitched sounds. The different pitches relate to which hole you press your finger on. When blowing into an instrument, different sounds will most likely be made.


 * Physics Talk**
 * Sound is a longitudinal or compressional wave.
 * The medium of the sound is in the air.
 * Nodes are located at the closed point of waves and the minimum of the amplitude.
 * When at the open end of the tube, the antinodes are located where the amplitude is at its maximum and the sound is the loudest.
 * Sound waves move around by avoiding barriers or moving around them.
 * Diffraction: the ability of sound waves to spread out or change direction as they emerge from an opening.
 * When the opening is smaller, the diffraction is larger.
 * The wavelength and the volume are determined by the size of the opening.
 * The displacement of air molecules is zero.
 * The frequency and pitch decrease when one end of the tube is closed.
 * Open tube: ½ lambda

1. The medium of the sound is the air. The sound is diffracting when one travels through the air. It is able to get through different barriers. 2. The diffraction of waves includes the ability to find openings, to change direction, and to bend. 3. The speed of a wave is equal to the wavelength multiplied by the frequency. If the speed would remain constant, then the wavelength and frequency would be constant.
 * Checking Up**

1. a) Waves produce the sounds. b) If you pluck the string, you produce a compressional wave and if you blow into a pipe, it is a transverse wave. 3. a) 11 meters b)
 * Physics To Go**

c) L = (n) (1/4) (lambda)19 = ¼ lambda wavelength = 44 meters

d) If the wave is larger, the frequency must be lower. Thus, the two are inversely related. The speed must remain the same . 4. a) It is about 12 meters long.

b) v = frequency x wavelength 340 = (f) (12) f = 28.3 Hz

c) It would be 6 because since it is open, it has to be double.

d) v = frequency x wavelength 340 = (f) (6) f = 56.7 Hz

5. It should be 4 meters long. The frequency is now greater, approximately 85 Hz. 6. a) This is known as diffraction. b)

7. V = d/t 340 = 1600/t t = 4.71 s


 * What do you think now?**
 * Flutes and organs produce sound through tubes. One side of the tube has an open end, while the other has a air that you blow into to put air into the instrument. Antinodes are present due to the open end of the tube. Antinodes have maximum amplitude and are the loudest part. The longer the length of the tube, the lower the frequency. Wave speed and frequency are directly related. Thus, if you were to increase wave speed, frequency would be increased, too. Temperature is a key factor when finding wave speed. Wave speed will always remain constant.