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Section 1
What Do You Think? 5/9/11 Guitarists and violinists today make different sounds by pulling at the different strings attached on the instrument. They position their hands all the way down because the shorter the chord the higher pitch the noise will be.

Physics Talk Summary 5/9/11 Sound is caused from vibrations. Variables are the things that change in an experiment. Length and tension on strings are the variables that cause a change in the pitch of an instrument. Pitch is how high or low the sound is, it has nothing to do with volume. As the tension increases, the pitch is higher and as the string is shorter, the pitch is higher. Vibrations cause sound from a percussion instrument.

Checking Up Questions 5/9/11 1. As the tension increases, the pitch is higher. 2. The pitch is higher when the string is shorter. 3. The mass increased the tension so the pitch was higher. 4. Vibrations are what causes sound from a percussion instrument.

Physics Plus 5/10/11 f= frequency T= tension m= mass of string L= length of string

f=square root(T/4mL) 2f=4T -doubling frequency, requires 4 x tension 2f=(1/4) 1/squareroot)L) -doubling frequency, requires 1/4 the length

Quadrupling the mass of the string cuts the frequency in half.

You have to make the string four times the size, so instead you choose the material or change the thickness and length of the string.

Physics To Go 5/10/11 1a) Turning the peg on the end of the instrument, or adding or taking away mass. b) If you increase the tension, it will increase the pitch. Square root relationship. 2a) By pressing their fingers down on the strings at different places on the strings. b) The shorter the length of the string the higher the pitch will be. The larger the length the lower the pitch. Inverse square root relationship. 3a) You make the strings thicker or thinner. b) You do the same thing. 4) If you changed both, the pitch would either be higher lower or the same depending on how you changed each. 5a) They are able to play different notes after it is tune because they change the tension and the length of the strings which changes the sound. 5b) To tune a guitar you fix the strings and make them either shorter or longer. You also adjust it by adding tension. To tune a piano by tightening the knobs which increases the tension 6a) The purpose of the knobs are that they tighten the strings which add tension. 6b) Guitars need tuners so you can produce a variety of different sounds and pitches with them. 6c) The tension becomes weaker and the pitch is lower 7a) The frets on a guitar decide the guitars length .  7b)They dont have frets. 7c) They need more finger accuracy because they don't have frets.

What Do You Think Now 5/11/11 Guitarists and violinists make different sounds by tuning their instruments. They hold the strings to make them shorter and tighten them with the knobs if they want to pitch to be higher, and loosen them to make it lower. If someone where playing the airguitar and trying to make high pitched noises, they would hold their fingers to make the strings as short as possible.

Section 2
What Do You Think? 5/11/11 The water moves to make a wave because the top of the wave is moving faster than the second part of the wave so it crashes down on shore over the bottom of the wave.

Physics Talk Summary 5/10/11 Crest is the position of max amplitude on a wave. Trough is the position of minimum amplitude. Amplitude represents the amount of energy of a wave has. Frequency is how many waves come at a time (always expressed in seconds). # of wave/1 sec=1/s= hertz. Period (T) is how many seconds it takes for one wave to pass. # sec/1 wave= s. T=1/f. Wave length is the distance from one point on the wave to the same point on the next wave. Wave speed is total distance/total time. V=wave length/period(T)= wave length x 1/period(T). Wave length equation: V=wave length(frequency). Medium- the substance that carries the wave. Transverse waves- a type of wave that moves side to side but the energy of the wave moves up and down. Energy travels perpendicular to the particle motion. Longitudinal wave- Particles move back and forth and the energy moves in the same direction. Energy travels parallel to the particle motion. Pulse- a single disturbance in the medium. In order to be a wave there has to be multiple, regular pulses. Wave speed depends only on the medium.

Checking Up Questions 5/11/11 ﻿1) A wave is the transfer of energy through an object without the net transfer of mass. 2) A transverse wave is when the direction of the medium is perpendicular to the direction of the wave, and a compressional wave is where the medium is parallel to the direction of the wave. 3) A node is the motionless spot on a standing wave and an antinode is where there is the biggest displacement on a standing wave.

Physics To Go 5/11/11 1a) amplitude- We measured 10 centimeters out, 20 centimeters out, and 30 centimeters out. That ended up being our amplitude. wavelength-  frequency-  speed- We took the distance that the spring went and divided it by the time it took to reach that distance.  b) amplitude- meters wavelength- meters frequency- 1/s speed- m/s c) Amplitudes doesn't direct to anything, wave speeds depends only on medium. 2a) As you shake the coiled spring more rapidly, the waves become bigger. b) The size of the wave changes as you shake it more rapidly. The speed also changes because it moves quicker. The speed is higher. c) The amplitude of the wave stays the same. 3) You can measure the wave length by measuring from one point on the wave to the same point on another wave. 4) The frequency is the number of vibrations over time. You would be able to measure the frequency by seeing how many waves are made compared to the amount of time you were recording. 5a) The units of wavelength are meters b) The units of frequency are Hertz. It is the number of waves per time 1/time c) Speed is m/s d) You can measure the speed with these by the wavelength times the frequency. e) meters (wavelength) x 1/seconds= meters/ seconds 7a) longitudinal waves are ones where the energy is parallel to the medium and a transverse wave is one where the energy is perpendicular to the medium. b) Coiled springs can be either. They can be a transverse wave if the person is moving it from side to side. They can be longitudinal if the person pushes to spring forward and backwards. c) The other wave was generated 12) Speed= meters/ seconds speed= 4.5/2.64  = 1.7 m/s

Physics Plus 5/13/11 amplitude: 4 m period: 10 s/2 cycle= 5 s/cycle frequency: 2 cycle/10 s= .2 Hz wavelength: 8 m wave speed: 8 m*.2 Hz= 1.6 m/s

What Do You Think Now? 5/13/11 Water moves to make a wave because wind is the medium. It travels perpendicular to the medium so it is transverse. The water moves up and down as well so there is an amplitude.

Section 3
What Do You Think? 5/13/11 Pitch gets higher when you make the string shorter.

Physics Talk Summary The length of the string determines the wavelength. The wavelength is double it. To get a higher frequency, shorten the string. Wave speed is length times frequency. In an inverse relationship, when one decreases, the other increases. Frequency the shorter the wavelength- this is an inverse relationship. Increasing tension doesn't affect wave length. The frequency increases though so the wave speed does too. The larger the tension, the larger the acceleration so the strings will vibrate faster. When the wave speed increases so does the frequency and pitch. This is a direct relationship. As one goes up so does the other. The thicker the string, the slower the vibrations travel down. L(length)= n(number) x lambda/ 2 T= time of vibrations/ 10 frequency= number of vibrations/ time

Checking Up Questions 1) When the wave length is smaller the frequency is higher. The equation is lamda = 2L/n 2) As the tension increases, the pitch increases. The more the tension, the larger the accelerations so the strings vibrate faster. That increases the pitch. 3) The higher the tension, the higher the frequency. As the frequency increases, the wave speed increases. 4) L= n x lambda /2

What Do You Think Now? 5/18/11 The pitch changes when you change the tension in the string because if you make the tension increases, the pitch increases because the speed of the wave gets faster, so more waves can travel through per second. The reason why is because the particles are tightly joined so it is easier to get the other particles to move. It's a direct square root relationship.

What Do You Think?
5/18/11 When you blow into the instrument and cover up some of the holes, the sound either travels farther or shorter. This changes the length of the instrument and therefore changes the pitch.

Physics Talk Summary 5/18/11 Sound is a compressional wave. The medium that sound travels through is air. At the bottom of a test tube there is no vibration and the amplitude is zero so there is no sound (node of a wave). At the open end, it is the loudest it can go and the amplitude is at its maximum (antinode of a wave). 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 smaller the opening the more diffraction. 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. The displacement of the air molecules are zero. When one end is closed, the pitch and frequency decrease. If the both ends are open it is 1/2 lambda. The wavelength is double then if it were closed.

Checking Up Questions 5/18/11 1. The medium is air. Sound travels through the air using diffraction. It travels in wave form and is able to get through openings in order to be heard. 2. Waves diffract by finding openings and bending and changing directions in order to get through them. 3. The speed of a wave is the wavelength times the frequency. If the wave speed is constant than the frequency and wavelength are constant to.

Physics To Go 5/19/11 1a) They are caused by standing waves, and they both have harmonics that are octaves apart. b) The sounds comes from the strings as opposed to the air from your mouth. The strings have nodes at both ends, and the tubes have nodes as well as antinodes. 3a) I is 11 meter b) c) Open pipe is 22 meters, closed pipe is 44 meters. d) They are indirectly related when speed remains constant. 4a) 12 meters b) velocity/wavelength=340/12= 28.3 Hz c) 6 meters d) velocity/wavelength=340/6= 56.6 Hz 5) The frequency would be a lot higher because the pipe is 1/3 the length of the 3 meter pipe. 6a) It's called diffraction b) 8) v= d/t 340= 1600/t t= 4.71 s

What Do You Think Now? 5/20/11 Flutes and organs produce sound through air going through the tubes. The antinodes at the end of the open ends of the tube produces a loud sound. If a wave speed is increased, the frequency has to increase. If the wave speed decreases, the frequency has to decrease. The shorter the tube, the higher the frequency.