Chapter+5

=Chapter 5= toc

Section 1
In this picture I see a string attaching from one end of the table to another. In the middle there is a can holding it up slightly, while at the end there is a weight holding it down. One person strums the string and the other person kind of falls backwards. Guitarists and violinists make different sounds by tightening or loosening the strings on the instrument. When doing the air guitar, to make a higher pitch, the person would move their fingers as close to the strum finger as possible.
 * What do you see/think?**

A road technician's job for a rock group is to set up all of the sound equipment for a concert. This means speakers, microphones, and etc. What they do with this equipment is connecting all of the wires and mixing the sounds of each speaker. They are also in charge of managing the sound during the concert. They can add sound effects or synchronize sounds with the music.
 * Career as a sound technician**

http://www.bls.gov/oco/ocos109.htm

- To produce sound, there must be a vibration - Vibrate: Move back and forth rapidly - Variable: Something that can change or vary during an investigation - Pitch: How high or low a note is - Length and tension are the two variables that affect pitch - The shorter the string, the higher the pitch - Adding mass increases tension, which makes the pitch higher - Instruments work by vibrating
 * Physics Talk**

1. As tension increases, the pitch becomes higher. 2. The smaller the length, the higher the pitch. 3. By adding more mass, the tension increased, via higher pitch. 4. Sound is produced in percussion instruments by striking it to cause a vibration.
 * Checking Up**


 * Inquiring Further**

Dame Evelyn Glennie is an accomplished musician even though she is deaf. In her essay "hearing" she explains how people have a misconception of what being deaf actually means. This is very interesting because she refers to sound as a specialized form of touch. This actually makes sense though because hearing has to do with vibrations, which make sound. So they type of vibration represents what pitch she is actually performing on her instruments. She also talks about how hearing is not only a sound, but a feeling. She makes a reference of a large truck going by and making vibrations along with a sound. She can sense these vibrations to interpret what the pitch is. Overall, this article is very interesting in her actual interpretation of what sound is.

1a. The tension can be increased in a vibrating string by increasing the mass connected to the string. b. Changing the tension changes the pitch. The more tension the higher the pitch. 2a. You can change the length of the string by pressing down on the string in different spots. b. Changing the length of the string changes the pitch. Increased length means the lower pitch. 3a. You could change the tension and still keep the same pitch if you also change the length of the string. b. You could also increase the tension to have the two balance out. 4. The sound or pitch would also change depending on which was changed more or less. If they were both balanced out, the pitch would be the same. 5a. A guitarist plays different notes by changing the position of his hands on the guitar. this changes the length of the string. b. An instrument tuner changes the pitch of the string by either tightening or loosening the string for a different tension. 6a. The purpose of these knobs is to keep the string attached, while at the same amount of tension. b. A guitar needs tuners to change the pitch the string gives off to make an appealing sound. c. As the string stretches length increases, thus a lower pitch. 7a. the purpose of frets is to change the length of the string. b. A violin and cello do not have frets. c. They need to be more accurate with their fingers because there are no frets like a guitar to show them where to put their hands.
 * PTG**

Guitarists or violinists make different sounds by changing the pitch. This is done by two different ways, amount of tension and length of the string. They would increase tension by tightening the string to make a higher pitch, they would do the opposite for a lower pitch. Also, they would decrease the length of the string by moving their hands closer together to decrease the length. This would make the pitch higher. If one were to pretend like they were doing the air guitar to make a high pitch, they would also move their hands together to decreases the length of the string.
 * What do you think now?**

Section 2
In this picture, I see a man holding a slinky connected to something sticking out of the ground. The slinky is waving up and down. There is also person above the slinky on a surfboard as if she were riding the wave. Water moves to make a wave by all of the water rising at the same time to make the wave shape.
 * What do you see/think?**

- Wave: A transfer of energy with no net transfer of mass - The greater the amplitude, the greater the energy - Medium: The material through which a wave can travel - For water waves, the medium is on the surface of the water - As waves pass each other, they add - Periodic Wave: a repetitive series of pulses - Crest: the highest point of displacement on a wave - Trough: The lowest point of displacement on a wave - Amplitude: The maximum displacement of a wave - The larger the amplitude, the louder the sound - Wavelength: The distance between two identical points in consecutive cycles of a wave - Frequency: The number of waves produced per unit time - Period: The time required to complete one cycle of a wave - Period=1/frequency - T=1/f - f=1/T - Transverse Wave: A wave in which the motion of the medium is perpendicular to the motion of the wave - Longitudinal (compressional) 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 largest - Sounds are compressional waves due to the compression of air - v=d/t - Wave speed=Wave frequency x wave length
 * Physics Talk**

1. A wave is defined by a transfer of energy with no net transfer of mass. 2. The medium of a transverse wave is perpendicular to the direction of the motion of the wave while longitudinal is parallel 3. A node is the point of the wave where the medium has no motion, while an antinode is the point of max displacement
 * Checking Up**


 * Physics Plus**

1a. Amplitude was calculated by finding the max displacement of the wave. Wavelength was done by taking two identical points on the wave and measuring the displacement. Frequency is measured by the amount of times our hands went back and forth to create a wave. Wave speed was measured by taking the total distance and dividing it by the total time. b. Amplitude: Meters. Wavelength: Meters. Frequency: Hertz (Hz). Speed: m/s. c. Frequency and wavelength are both inversely related while amplitude has no affect on any of these terms. Also, wave speed is only dependent on the medium of the wave. 2a. By shaking the spring more rapidly, frequency would increase and wave length will decrease because they are inversely related. b. Wavelength and frequency both change. c. Amplitude and wave speed do not change. 3. You would measure wavelength by taking two identical points and measuring the displacement between the two. 4. You would measure frequency by counting how many waves are completed for every second. 5a. Wavelength: Meters b. Frequency: Hertz c. Speed: m/s d. You find wave speed by multiplying the frequency by the wavelength. e. Frequency(s) x wavelength(m)=speed(m/s) 6a. A standing wave is a wave that remains constant b. c. You would find the wave length by taking two identical points on the standing wave above and measure the displacement. 7a. Transverse waves travel perpendicular to the direction of motion while longitudinal are parallel. b. For a transverse wave, the spring would move side to side, while in a longitudinal wave it wold move up and down where you could actually see the spring compress. c. The other wave was generated due to the law of conservation of energy, the wave hits the end of the spring and bounces back. 8a. We made the wavelength shorter by increasing the frequency. b. We made the wavelength longer by decreasing the frequency. 9a. b. 10a. (1)(.5)(wavelength)=10 wavelength= 20 m b. f=1/T f= 1/2 Hz c. wavespeed=f*lambda wavespeed=(.5)(20) wavespeed= 10 m/s 11a. The amplitude would be 5 cm because you add them. b. If they were on opposite sides the amplitude would be 1 cm because you subtract. 12. v=d/t v=9/2.64 v=3.41 m/s 13a. The position for the clothes is the nodes because there is no movement. b. (3)(.5)wavelength=9 wavelength= 6 m. c. The wavelength could be 3 meters or even 1.5 meters. As long as you always divide by 2.
 * PTG**

After studying the motion of waves in this section, we can now describe the motion of water. Water is very unique in its motion. This motion is best described by using the concept of waves. Water moves with a transverse wave (perpendicular to the direction of the motion). The wave starts off with a certain amount of energy, creating a certain amplitude. This wave will continue to have the same amount of energy due to the law of conservation of energy. When two waves meet, they add and continue in their respective directions without losing any energy. If one were to examine these waves, they can find the wavelength by measuring the distance between to identical points of the wave. They can also find that there is a very high frequency in waves because there are many waves in water.
 * What do you think now?**

**Section 3**
In this picture I see two people playing an instrument. One of them has a string attached to a broom and the other has a harp with a bunch of strings at different lengths. The pitch changes when you change the tension of the string because the greater the tension the higher the pitch.
 * What do you see/think?**

- A vibrating string produces a standing wave from both ends of the string - Length of the string determines the wavelength - Length of string is always 1/2 the wavelength of the lowest frequency - Higher the frequency the higher the pitch - v=f(lambda) - To get a higher frequency, you must decrease the wavelength - The shorter the wavelength, the higher the pitch - f=v/lambda - Increase in tension does not change the wavelength - An increase in tension increases the wavespeed - Increase in tension also increases the frequency - The thicker the string (mass), the less it will vibrate, creating a lower pitch - L=n(lambda)/2
 * Physics Talk**

1. Decreasing the wavelength increases frequency because they have an inverse relationship. 2. The tension of a string is related to its pitch because by increasing tension, it causes the string to vibrate more to return to its rest position. This increase in vibration creates an increase in frequency, thus a higher pitch. 3. Tension relates to wave speed because an increase in tension causes the string to vibrate more rapidly. This also causes a higher acceleration in the string, creating a higher wave speed. 4. L=n(lambda)/2--->Length of string=#antinodes(lambda)/2
 * Checking Up**

The sound's pitch can be related to the tension in a string. An increase in tension causes the string to vibrate more to return to its resting position. This increase in vibration causes an increase in acceleration. Therefore creating a higher wave speed. The higher the wave speed the higher the frequency due to their direct relationship. This increase in frequency therefore creates a higher pitch.
 * What do you think now?**

**Section 4**
In this picture I see a group of kids all holding an object and blowing into it to play it as if it were an instrument. One is holding a shower head and another is holding a bottle. Flutes and organ pipes produce sound by blowing into them. By blowing into them, it vibrates and creates a certain pitch. This pitch is produced from a standing wave.
 * What do you see/think?**

- Sound is a compressional (longitudinal) wave - A closed tube has a node at the closed end of the tube - An open tube has an antinode at both ends of the tube - Diffraction: The ability of sound waves to spread out or change direction as they emerge from an opening - The smaller the opening, the more sound waves diffract - The less diffraction, the louder the sound - The displacement of air molecules in a closed tube is zero at the closed end - v=f(lambda) - Open Tube: L=n1/2(lambda) - Closed Tube: L=n1/4(lambda) ODDS ONLY
 * Physics Talk**

1. Sound travels through the air by spreading out, it also diffracts through openings. 2. Sound waves diffract by squeezing and bending through openings to spread out. 3. 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.
 * Checking Up**

1a. They produce similar sounds by both creating a standing wave. b. A string has a node at both ends while a tube has an antinode at one end. 3a. 11 meters is the length of the longest organ pipe. b. c. The wavelength is 44 meters because a closed tube is 1/4 the wavelength. d. A large wavelength represents a lower frequency because if wave speed remains the same, this means that wavelength increases while frequency decreases. 4a. The wavelength would be 12 meters because it is 4 times the length of the tube. b. v=f(lamba) 340=12f f=28.3 Hz c. The wavelength would be 6 meters because wavelength in an open tube is twice the length of tube. d. v=f(lamba) 340=6f f=56.6 Hz 5. The shorter the pipe, the higher the frequency. The pipe previously is three times greater than this pipe. 6a. This is called diffraction, where sound waves bend or curve through an opening to spread out. b. 7. v=d/t 340=1600/t t=4.71 s.
 * PTG**

Flutes and organ pipes produce sound in a unique way. By blowing into them, it produces a standing wave that travels through the pipes. At the opening of this pipe, there is an antinode that creates a vibration, thus producing the sound. Some of the instruments have bends or curves, this creates diffraction. The smaller the opening, the lower volume. So a lot of diffraction is not good for instruments in producing a loud sound. They also produce sound through their wave speed. If an organ pipe or flute has the same wave speed, this means that the frequency decreases as the wavelength increases.
 * What do you think now?**