How do noise-cancelling headphones work? (hint: the answer involves a microphone and a type of interference)

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1 Name: Period: Cover Requirements: 1. Name of unit 2. Picture of something from the unit Empty Map Questions: Will a speaker vibrate in space? Explain. Why does grabbing a cymbal make it quiet? How do noise-cancelling headphones work? (hint: the answer involves a microphone and a type of interference) Can phones emit enough radiation to cause cancer? Explain. What specific frequencies of ultrasound is used to see babies in a womb? PSE 4 1

2 Target # 4.1 PSE Unit 4 (Waves & Sound) Learning Targets Waves & Sound I know the characteristics and properties of longitudinal and transverse (and surface) waves and how waves interact 4.2 I can solve problems using the speed, frequency, and wavelength (and period) of a wave 4.3 I know how sound is created, transmitted, and how frequency/amplitude affect what you hear 4.4 I can identify the parts of the EM spectrum, and explain how wavelength, frequency, and energy are related Additional textbook reading for each target: 4.1: Section 17.1, p : Section 17.2, p a 4.3: Section 17.4, p : Section 18.1, p ; 18.2, p Current SI Units of Measurement: Frequency: Period: Wavelength (λ): Sound Intensity: Previous SI Units of Measurement: Distance: Speed/Velocity: Time: Volume: Mass: Force: Acceleration: Work/Energy: Power: PSE 4 2

3 Unit 4: Waves & Sound Vocab Amplitude - The height of a wave from the midline to the crest Quizlet shortlink: Constructive interference - Two waves meet on the same side, and the crest of one wave meets the crest of another wave. The resulting wave is larger than either of the starting waves Destructive interference - Two waves meet on opposite sides, and the crest of one wave meets the trough of another wave. The resulting wave is smaller than either of the starting waves Electromagnetic spectrum - Range of all electromagnetic radiation. Listed below from longest to shortest wavelength: Radio wave - Part of the EM spectrum. Longest wavelength (lowest frequency). Microwave - Part of the EM spectrum. Shorter wavelength (higher frequency) than radio waves. Infrared rays - Part of the EM spectrum. Shorter wavelength (higher frequency) than microwaves. Visible light - Part of the EM spectrum, visible by human eyes. Shorter wavelength (higher frequency) than infrared rays. Ultraviolet rays - Part of the EM spectrum. Shorter wavelength (higher frequency) than visible light. X-Rays - Part of the EM spectrum. Shorter wavelength (higher frequency) than ultraviolet rays. Gamma rays - Part of the EM spectrum. Shortest wavelength (highest frequency). Frequency - How often something occurs in one second. Unit: Hz (Hertz) Hertz (Hz) - Unit of Frequency Infrasonic - Any sound below the range of hearing. In humans, ~<20 Hz. Longitudinal wave - Type of wave where the vibration and direction of travel are parallel. (Example: Sound) Medium - The material through which a wave travels (example: the medium for sound is air) Period - The length of time it takes for one complete wavelength to pass a fixed point. Unit: s (second) Pitch - How a sound is perceived by your ear. Higher frequency = higher pitch. Sound - Mechanical (requires a medium) pressure wave. Longitudinal wave. Transverse wave - Type of wave where the vibration and direction of travel are perpendicular. Example: shaking a rope. Ultrasonic - Any sound above the range of hearing. In humans, ~>20 khz (20,000 Hz). Wavelength (λ) - The distance between two crests or two troughs on a wave. Units: m (meter) 3

4 amplitude compression crest interference nodes & antinodes rarefaction trough wavelength Term and Definition (1) Picture (2) (3) (4) (5) (6) (7) (8) Use p in the textbook 4

5 TOPIC/OBJECTIVE: LEARNING TARGET: Intro to Waves DUE DATE: TEXTBOOK PAGES: 17.1, p I know the characteristics and properties of longitudinal and transverse (and surface) waves and how waves interact 2-3 YOUTUBE / WIKIPEDIA FACTS (NO DATES, NO PEOPLE) NOTES: CONNECTIONS. MAKE A CONNECTION BETWEEN THIS TOPIC AND SOMETHING ELSE (SOMETHING YOU HAVE READ, EXPERIENCED, HEARD ABOUT, ETC...) 5

6 1. Middle C on a piano has a frequency of Hz. What is the length of time (the period) between each vibration? List your variables and their values. Write the equation you will use. Show your work. Answer (with units) 2. Find the wavelength (λ) of an ocean wave if it has a frequency of Hz and is traveling at a speed of 1.97 m/s. List your variables and their values. Write the equation you will use. Show your work. Answer (with units) 3. The fastest wind speed ever recorded would have made a flag ripple at 689 Hz with 15 cm between each ripple. How fast was the wind blowing? 4. Calculate the frequency of a sound wave traveling along an iron railroad track. The speed of sound in iron is 5,120 m/s and the wavelength of each pulse is 32 cm. 5. You are stuck behind a car and notice that each of your turn signals are flashing at a different rate. Calculate the frequency (Hz) and period (s) of both of your turn signals. a. Your turn signal blinks 5 times in 4.67 s. b. In seconds, their turn signal blinks 12 times. Frequency (Hz) = cycles per second Period (s) = seconds per cycle 6. A curse word is bleeped on a radio at speaker. The bleep is a sound wave at 1000 Hz, and the speed of sound at sea level is m/s. What is the distance (wavelength) between each compression from the 7. Elephants use infrasound to communicate. A male elephant uses a 12 Hz frequency in water. A hydrophone registers a wavelength of m between each compression. What is the speed of sound in water? 8. The P-wave of an earthquake travels ~5,000 m/s through granite and has a wavelength of 490 m. What is the period (s) and frequency (Hz) of the earthquake wave? 6

7 TOPIC/OBJECTIVE: LEARNING TARGET: Sound DUE DATE: 4.3 I know how sound is created, transmitted, and how frequency/amplitude affect what you hear 2-3 YOUTUBE / WIKIPEDIA FACTS (NO DATES, NO PEOPLE) NOTES: TEXTBOOK PAGES: 17.4, p CONNECTIONS. MAKE A CONNECTION BETWEEN THIS TOPIC AND SOMETHING ELSE (SOMETHING YOU HAVE READ, EXPERIENCED, HEARD ABOUT, ETC...) 7

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9 Section of EM Spectrum: Potential Uses: (include at least one drawing for each section) Use p

10 1. What are the two main types of waves, and what is the main difference between them? 2. Draw a transverse wave and label the amplitude, wavelength, crest, trough, and midline (rest position). 3. What happens when 2 waves collide with each other? What two terms describe how they interact? 4. How can you determine the amount of energy in a wave? 5. What type of wave is a sound wave? Describe how sound is transmitted from an object to your ear. 6. What part of a sound wave is pitch related to? Loudness? 7. What is the name for sounds that are below the hearing range of humans? Above the hearing range of humans? 8. What is the full range of frequencies of electromagnetic radiation called? 9. Write the different types of electromagnetic waves in order from longest wavelength to shortest wavelength. 10. What is the speed of a wave in a spring if it has a wavelength of 0.15 m and a frequency of 2.5 Hz? 11. Three complete wavelengths pass a fixed point once every 2 seconds. What is the frequency of the wave? What is the period of the wave? 12. If you want to make a sound wave louder, what part of the wave do you need to change? What about pitch? 13. A deep-water wave has a wavelength of 10.0 m. If it travels at 3.9 m/s, what is the wave s frequency? What is the wave s period? 14. Draw a high frequency and a low frequency wave. Be sure you know which one is which. 15. Draw high amplitude and low amplitude wave. Be sure you know which one is which. 10