Chapter+5

=Section 1= toc What do you think?
 * Guitarists and violinists make their instruments make different sounds by applying different amounts of pressure to parts of the string. If they want a lower or higher sound they will place their fingers to make the string shorter or longer. To make a high pitch noise the hand that choses which notes you are playing would be closer to the hand that is stroking the guitar, not the end.**

Physics Talk
 * Vibrate- move back and forth rapidly**
 * Variable- something that can change or vary during an investigation**
 * Pitch- (in music) how high or low a note is**
 * Increasing tension or decreasing the length of the string will increase the pitch. To write a mathematical equation to describe these relationships, one must know the measure of each pitch.**

Checking Up 1. **When tension is increased the sound of the pitch is higher** 2. **When the length of the string is decreased the pitch is higher** 3. **Adding mass made the string more tense, making the pitches higher** 4. **Vibrations are made to create sound in a percussion instrument**

Physics Plus
 * F = SQRT T/4 mL**
 * f= frequency**
 * T= tension**
 * m= mass of string**
 * L= length of string**


 * Doubleing the frequency requires 4x Tension**
 * Doubling frequency requires 1/4 Length**

Inquiring Further 3. **Dame Glennie is able to distinguish the rough pitch of notes by finding where she felt the vibration of sound on her body. She feels low sounds in her legs and high sounds in her face, neck and chest. Since Dame is only deaf she sees the instruments move and vibrate while she plays. Electrical signals are generated in her ear along with various parts of other information from the other senses are combined in her brain to create a sound picture.**

Physics To Go 1a. **By adding mass or taking away mass.** 1b. **If you add mass the pitch will be higher** 2a. **To make different notes or make different sounds one could move their fingers. By making the string shorter it increases pitch and visa versa** 2b. **Quadruple the length you have half the pitch** 3a. **Increase the length** 3b. **Make the wire thicker or thinner or change the tension** 4. **It would either be really high pitched or really low pitched, either way it would create a different sound** 5a. **The violinist or guitarist can place their fingers on different frets or change the tune of the guitar** 5b. **The tighter the wires are overall the sound of the instrument will be higher than if the wires were loose** 6a. **These knobs change the note that the guitarist is in. They make the strings looser or tighter** 6b. **It needs tuners to play different notes** 6c. **The pitch will get lower** 7a. **Frets tell where to place fingers to play different notes and play different sounds** 7b. **No** 7c. **They do not have frets therefore it is harder to see where you need to put your fingers, it is more a memory of sound**

What do you think now? **Guitarists and violinists make their instruments make different sounds by applying different amounts of pressure to parts of the string. If they want a lower or higher sound they will place their fingers to make the string shorter or longer. To make a high pitch noise the hand that choses which notes you are playing would be closer to the hand that is stroking the guitar, not the end. However hard the person playing the instrument decides to stroke it will determine the loudness, but not the pitch. The pitches of the wavelengths depend on pressure applied and length of the strings.**

=Section 2= What do you think?
 * The way the waves move in the ocean is similar to a longitudinal wave when coming towards the shore. The particles move back and forth as they are also traveling straight towards the shore and the waves are moving in the same direction on the medium.**

Physics Talk __**Interference**__
 * Crest- position of the max amplitude (distance) on a wavelength**
 * Trough- position of minimum amplitude on a wavelength**
 * Crest and Trough have the same value although crest is positive and trough is negative**
 * Amplitude represents the amount of energy a wave has**
 * Frequency- how many waves come in a unit of time- expressed in seconds (f) anything per second (1/s) = Hz**
 * Period (T)- how many seconds it takes for one wave to pass (# sec/1 wave = s)**
 * Frequency and period are reciprocals**
 * Wave length (¥)- the distance from one point on a wave to the same point on the next wave**
 * Wave Speed- the speed it takes for one wave to travel from one spot to another. Total distance/total time**
 * V = ¥/T = ¥ X 1/T = ¥f**
 * Wave speed equation = V = ¥f**
 * Medium- the substance that carries the wave**
 * Transverse wave- the particle moves up and down while the wave moves perpendicular down the medium**
 * Longitudinal wave- the particle move back and forth on the medium as well as the waves moving the same direction.**
 * Pulse- single disturbance in the medium, a wave has regular and repeated pulses**
 * **property of waves**
 * **when two waves in in the same place at the same time**
 * **Constructive- when crest of 1 wave meets crest of another, the amplitudes ADD together (same for two troughs)**
 * **Destructive- when crest of 1 wave meets trough of another, the amplitudes SUBTRACT**
 * Standing waves are a pattern produced by the interference of a wave and it's reflection.**
 * **Antinodes (Ω) are the regions of constructive interference**
 * **Nodes (** •**) are the regions of destructive interference**
 * **n = Harmonic number**
 * **L = n1/2¥**
 * **n = antinodes**

2. **A transverse wave is a wave in which the motion of the medium is perpendicular to the motion of the wave. A longitudinal or compressional 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 (wave pattern that remains in a constant position) where the medium is motionless. An antinode is a point on a standing wave where the displacement is the largest.**
 * Checking Up **
 * 1. ****A wave is a transfer of energy with no net transfer of mass.**

Physics To Go 1a. 1b. **Amplitude and wavelength are measured in meters. Frequency is measured in Hz (1/s). Speed is measured in meters per second.** 1c. **Wavelength, frequency, and speed are related by the wave formula: speed= (wavelength)(frequency).** 2. **The frequency would increase, wavelength would decrease, and speed would remain the same. The amplitude would not change.** 3. **Using a ruler, you could measure the distance from one peak to the next peak.** 4. **Count the number of waves that pass the designated point in a certain amount of time, and then convert to Hz.** 5a. **Meters** 5b. **Hertz (1/s)** 5c. **Meters per second** 5d. **The wave speed is equal to the wavelength multiplied by frequency.** 5e. **The units used for wavelength and frequency multiplied provide the unit for wave speed.** 6a. **A standing wave, also called a stationary wave, is a wave pattern that remains in a constant position.** 6b. 6c. **To determine the wavelength by looking at a standing wave, measure the distance between two non consecutive nodes.** 7a. **A transverse wave is a wave in which the motion of the medium is perpendicular to the motion of the wave. A longitudinal or compressional wave is a wave in which the motion of the medium is parallel to the direction of the motion of the wave.** 7b. **In a transverse wave, the coiled spring**

Physics Plus

a. amplitude- 4 m b. period- 5 seconds per cycle c. frequency- .2 Hz d. wavelength- 8 m e. wave speed- 1.6 m/s

What do you think now?
 * A water wave is like a transverse wave on a coiled spring. We experimented in class with a spring and were told by the textbook that water waves and spring waves move around the same way. They have a certain amplitude that determines the height and wave speed that determines how fast the wave is traveling on the water.**

=**Section 3**= What do you think?
 * The pitch changes when you change the tension in the string because it is making the string a different length and makes it harder for the string to rotate.**

Checking Up 1. **Decreasing the wavelength increases the frequency of a wave. Frequency is equal to wave speed divided by wavelength, therefore a smaller wavelength creates a larger frequency.** 2. **An increase in tension on a string creates a higher pitch. The increase in the force acting on the string creates a greater acceleration of the vibrations of the string, making the pitch higher.** 3. **An increase in tension makes the wave travel faster down the string.** 4. **The length of a coiled spring is equal to the number of antinodes multiplied by the wavelength divided by 2.**

Physics Talk
 * Length of a String:**
 * **Determines the wavelength of a standing wave**
 * **Always 1/2 the wavelength of the lowest-frequency wave**
 * **Length of the coiled spring = (harmonic number x wavelength)/2.**
 * Pitch**
 * **The pitch of a note is related to the frequency of the wave**
 * **The higher the pitch, the higher the frequency**
 * **To get a higher frequency, you have to shorten the string or generate a smaller wavelength**
 * Wave Speed**
 * **Wave speed= wave frequency x wavelength**
 * **Decreasing the wavelength increases the frequency and pitch**
 * **Increasing the wave speed increases the frequency and pitch**
 * Tension**
 * **Increased tension in a string means that a portion of the string that is displaced to the side will feel a larger force pulling it back to its rest position**
 * **An increase in tension produces a larger force and a larger force will provide a greater acceleration on that portion of the string and make it vibrate faster- the vibration makes the disturbance travel more quickly down the string.**

What do you think now?
 * When the string is made tighter or looser, it affects the type of vibration produced, changing the pitch of the sound made. An increase in tension makes the string vibrate faster, and the disturbance travels more quickly down the string. Adding tension increases pitch and wave speed.**

=Section 4= What do you think?
 * Wind travels through the instrument and comes out the other end. When fingers are placed to produce notes they block the air from passing through.**

Physics Talk
 * Diffraction - bending of a wave around an obstacle or through an opening**
 * **wave length must be as big as or bigger than the opening**
 * **the bigger the lambda the more bending**
 * **smaller opening, more bending**
 * Closed end of a tube - node**
 * **pitch and frequency decrease**
 * **wavelength is doubled**
 * Open end of a tube - antinode - noise is created**
 * **forms a vibrating column of air**
 * **displacement of the air molecule is zero**
 * **wavelength is cut in half**

Checking Up 1. **The medium is air. Sound diffracts while traveling through the air. It can enter through different barriers or boundaries.** 2. **Waves diffract by bending and finding different openings. They will change direction in order to fit through different sized openings and barriers.** 3. **Wavelength X frequency = speed. When speed is constant, the frequency and wavelength are also constant.**

Physics To Go 1a. **Similarities- caused by standing waves, harmonics are octaves apart, changing length of string vs. tube effect the frequency** 1b. **Differences- string moves the air vs. mouth moves the air, string (nodes at both ends), tubes (node and antinode)** 3a. **11 meters** 3b. 3c. **Open pipe: 22 meters, closed pipe: 44 meters** 3d. **Wave length and frequency are indirectly related when speed remains constant. v = wave length X frequency** 4a. **12 meters** 4b. **340/12 = 28.3 Hz** 4c. **6 meters** 4d. **340/6 = 56.6 Hz** 5. **The frequency would be a lot higher because the pipe is 1/3 the length** 6a. **Diffraction** 6b. 8. **v = d/t**
 * 340 = 1600/t**
 * t = 4.71 s**

What Do You Think Now
 * Flutes and organs produce sound when air flows through the instrument tubes. Because the tubes have open ends, there is an antinode at the end which produces a loud sound. The shorter the tube, the higher the frequency or the longer the tube, the lower the frequency. If wave speed is increases the frequency has to increase. If wave speed decreases then the frequency has to decrease because of their inverse relationship. The wave speed stays constant unless the temperature of the room or area you are in changes.**