Ch5+MontantiJ

Jessica Montanti's Wikilog - Pd 6 CP Physics -Ms. Burns - 2010 Chapter 5 - Let Us Entertain You toc

=Section 1= = = What do you see? A girl flicks a string that has a weight on the end of it. By flicking the string the tension is adjusted the boy is blown away by the sound.

What do you think? Musicians make different sounds by learning how to use the instrument differently. For example, a guitar player positions his fingers differently, flicks different strings, and adjusts his strings differently to get a sound. If pretending to play the guitar you would have to position your fingers high on the guitar in order to make it appear you are making a high noise.

Physics Talk class notes parts of the wave length equations / measurements notes
 * to produce sound something must vibrate.
 * 2 variables are length and tension.
 * pitch: of the sound of a vibrating thing (the string)
 * when you add mass to the hanger on a string you also changed the pitch.
 * pitches goes up when tension increases and when length of string decreases.
 * equilibrium: position of string
 * crest: position of max amplitude
 * trough: position of minimum amplitude
 * amplitude: the distance
 * medium: substance that carries the wave
 * wave length: the distance from one position on a wave to the same position on the next wave
 * frequency: the number of waves in one period of time (how many waves per second)
 * units: hertz Hz: 1/s # of waves/seconds
 * # of seconds / 1 wave = period
 * Period = T= 1/f
 * wave speed - how fast a wave is moving
 * v: d/t : lambda/period <--- wave speed equation
 * pulse: a single disturbance
 * traveling wave: one that is continuous

Look up "Career as a sound technician" on the internet and find out what a road technician does with a rock group. With a rock group and road technician would make sure the sound of the group is being processed as clear as possible. They do sound checks and run the microphones to ensure that the audience can hear the performers and everything is working as planned. - http://www.bls.gov/oco/ocos109.htm - http://musiced.about.com/od/musiccareers/p/soundtechnician.htm



Physics Plus 1 & 2 decreasing the length of the string increasing the frequency. doubling frequency calls for 4 times the tension

3. Increase the mass of the string you will get a lower pitch

4. The different thicknesses of wire make a different pitch because the thinner ones vibrate more while the thinner ones create a deeper sound. The mass and length are changed so it will work in the piano for thick wires and the thin ones are adjustable also. The different wires give the range of sound.

Checking Up 1. becomes higher 2. becomes deeper and lower 3. it gives it more tension making the pitch higher. 4. the sound is made by the instrument vibrating.

PTG 1. a. You change the tension by lengthening the string or shortening it. b. the more tension the pitch is higher

2.a. by holding the string in different positions. b. shorter the string --> higher the pitch

3. a. the pitch will stay the same when you add more tension to the string ....vice versa b. shorter the string the less tension you need in order to keep the pitch the same

4. depending on how much is changed the pitch would be higher or lower or the same

5. a. the change in tension and length of the strings after tuned makes the guitar play different sounds. b. For a guitar you must fix the strings to be shorter or longer and add tension. For a piano you must make the knobs tighter this will increase the tension.

6.a. add tension by tightening the strings. b. the tuners are used to make different sounds and pitches c. the lower the pitch the weaker the tension

7. a. the frets decide the vibrating length b. dont have c. there are a lot more strings so you need to practice and make sure you have finger accuracy in order to get their right pitch.

Inquiring Further Evelyn Glennie explained how she is able to hear even though she is deaf. Her website explained that the act of hearing is the process of feeling the sound vibrations in more complicated way. She had to work harder in order to hear than the average person with good hearing because the higher frequency vibrations are tougher. She learned by holding her hands up against a wall while her teacher played, this way she became familiar with the notes. The vibrations allowed her to become a talented musician.

What do you think now? By moving your hands on the guitar you are changing tension when you lengthen or shorten the string. The more string there is left the lower the pitch will be and the less string the higher the pitch will be. If a musician wanted a high pitch noise they would hold their fingers tight around the string making it at short as possible.

=Section 2= What do you see? The girl is surfing the spring/ slinky. In the back round is in an ocean. There is a similarity between the waves in a spring and the waves in the water.

What do you think? The moon changes the tides of the ocean creating the waves we see that go up and down.

Physics Talk
 * wave: a transfer of energy with no net transfer of mass
 * the coiled spring is the medium through which the wave travels and through which the energy is transferred.
 * a unique feature of a wave is that as waves pass each other they "add" as they pass. then they continue to travel as if the other wave had never been present
 * periodic wave:is a repetitive series of pulses.
 * crest: highest point of the periodic wave
 * trough: lowest point of the periodic wave
 * node: position o a standing wave when there is always destructive interference.
 * antinode: position on a standing wave where there is constructive interference.
 * the number of anitnodes is called a harmonic- the harmonic number
 * n/2 thedda : L
 * interference: a wave property, when 2 separate waves are in the same place at the same time.
 * destructive interference: when crest meets w/ a trough and amplitudes subtract
 * constructive interference: when crest meets crest or trough meets trough and amplitudes add

Checking Up 1. a transfer of energy with no net transfer of mass 2. transverse: when the direction of the medium is perpendic to the direction of the wave compressional: where the medium is parallel to the direction of the wave. 3. node:position o a standing wave when there is always destructive interference.

PTG 1. amplitude, wavelength, frequency, and speed. a. amplitude: From where you started to where the pulse is. For the lab we measured 10 cm, 20 cm, 30 cm. wavelength: the crest to the end of the trough frequency:how much time the wave legnth happens...how many waves were in the spring. speed: the wave length times the frequency...the distance the spring went / the time it took to reach that distance. b. amplitude: meters wavelength: meters frequency: hertz speed: m/s c. amplitude is the only independent the others are related.

2.a. the frequency changes when the spring is moved faster. it becomes higher so the wavelength is shorter bc the medium is changing the speed. b. the speed becomes higher c. waves amplitude stays the same.

3. You can measure any point on the wave to the same point on the next wave.

4. To measure the frequency you would need a timer

5. a. meters b. Hertz, number of waves per time (1 time) c. m/s d. Wavelength X frequency e. meters x 1/seconds = meters / seconds

6. a. one that remains in a constant position b. c. measure one position on the wave to the same position on a different wave.

7a. Longitudinal the energy and vibration of the medium are parallel to eachother while transerve has particles that vibrate perpendicular to the energy. b. it can be transverse and longitudinal because transverse if the person is moving from side to side and longitude if the person is moving it forward and backward.

8. a. i would shake the wave more to increase the frequency to make it shorter b. i would shake the spring less to lessen the frequency to make it longer

9. a. 1 m, 2 m, 3 m, 4m 5m b. the more wave patterns --> the higher the frequency

10 a. 10 X 2: 20 meters b, 1/2 ..the respraprocal of the period c. 1/2 X 20 : 10 m/s

11. a. 10/2 3 + 2 5 there is one on top one on the bottom b. you would subtract them, amplitude would equal 1 meter 3-2

12. speed : m/s 4.5 X 2 / 2.64 3.41 m/s

13. a. nodes b. 6 meters -3 + 3 c. 3 meters and 1.5 meters

Physics Plus = =

class work: time: 10 seconds a. amplitude: 4 meters b. period: 5 seconds c. frequency: 1/5 d. wavelength: 8 meters e. wave speed: 16/10 1.6 m/s

what do you think now? Water makes waves when the wind is the medium. It is transverse because the medium (the wave) travels perpendicular to the wave. There is amplitude because as the wave move they move up and then down and then back up and then back down.

Essential Question: "the wave flees the place of creation but the water does not" = waves any time (string water slinky) the particles only jiggle up and down or side to side the source of the wave is the initial shake and then the wave travels outwards and away from but the particles don't move.

class notes:
 * resonance:
 * amplitude : the height
 * force something to vibrate at its natural frequency

=Section 3=

what do you see? A girl is playing on a harp like instrument and the strings are the instrument are vibrating. There is also a boy who has a string attached to a broom and is playing as if he has a harp. The boy has one string while the girl has many.

what do you think? Pitch changes when you change the tension because the string becomes tighter or looser making a different affect.

Physics Talk
 * length of the string determines the wave length
 * higher frequency --> shortern string
 * wave speed: length X frequency
 * the thicker the string the slower the vibrations will travel down
 * L (length) = n (number) X lambda / 2
 * T: time of vibrations / 10
 * frequency: number of vibrations/time.

Checking up Questions 1. indirect lambda = 2L/n 2. tension increases --> pitch increases. the more tension there is the larger the acceleration. 3. higher tension --> higher frequency. when frequency increases so does the wave speed. 4. L : n X lambda /2

What Do You Think Now? When the length of the string increases the wave length will increase also because they are directly proportional to each other. The pitch and frequency increase when tension is added to the string. The lower the frequency and velocity the thicker the string.

=Section 4= what do you see? A kid is blowing into a pipe while another kid is listening. The pipe is producing noises and the other children in the room are also making noises with pipes.

what do you think? You make sound by blowing into the pipe and changing the position of your fingers.

Physics Talk >
 * diffraction:sound waves spreading out or changing direction as they come out from an opening
 * open pipe: L: N1/2 X lambda
 * closed pipe: L: N1/4 X lambda

Checking up 1. medium: air The sound travels through air by diffraction and goes through openings to be heard. 2. By going to openings and changing their direction and form in order to go through those openings. 3. speed: wavelength X frequency. if one is constant the other is also.

notes: defraction: bending of a wave around an obstacle or through an opening....like when you use ur fingers to look @ the light.

PTG 1. a. They both make waves that are able to be heard b. They are different because a string is compressional and blowing a pipe is transverse

3.a. 11 meters b. c. L: n (.5) λ L: n (.5) λ 19: .5 λ 22 m d. There is only one antiode, therefore the larger the wavelength the lower the frequency.

4. a. 3(4) 12 meters long b. 340/12 : 28.3 hz c 3(2) = 6 m d. speed of sound / wavelength 340/6= 56 hz

5. 340/4 85 hz

6. a. diffraction b.

7. v=d/t 340 m/s = 1600/t t: 4.71 seconds