CHAPTER 14 Sound Doppler Effect A train passes by you with its whistle/horn blowing. You hear one pitch (tone) as the train is coming towards you and a.

Slides:

Advertisements

Similar presentations

The velocity of sound in glycerol is m/s

Advertisements

Doppler Effect Moving Source.

Doppler Effect.

PHY 102: Waves & Quanta Topic 5 Sound John Cockburn Room E15)

Doppler Effect & Redshift Gharib ESS

The Doppler Effect Thursday, October 26, First, a review from yesterday…

1© Manhattan Press (H.K.) Ltd. Source moving Observer moving Observer moving 11.5 Doppler effect Both source and observer moving Both source and observer.

Doppler Effect. What sound do you hear when a car races by at the race track? Or when an ambulance/police car speeds by?

DOPPLER EFFECT This is the apparent change in the frequency of a wave motion as noted by an observer when there is relative motion between the source.

D OPPLER E FFECT. R ECAP FROM L AST WEEK … Intensity Level (a.k.a., loudness) Sound Intensity.

Doppler Effect.

***Doppler effect….

Created by Joshua Toebbe NOHS 2015

Chapter 15.2 – Characteristics of Waves amplitude – the maximum distance that the particles of a wave’s medium vibrate from their rest position -in a transverse.

Chapter 10: Sound Section 1: The Nature of Sound

Doppler Effect Physics 11.

Speed of sound. Problem During a thunderstorm, lightning strikes 300 m away. If the air temp is 25 Celsius, how much time passes between when you see.

THE DOPPLER EFFECT. When the source of a sound is moving towards you, the pitch sounds higher than that of the source. When the source moves away from.

Chapter 14 Sound. Characteristics of sound 2 A special and important type of mechanical wave Speed of sound: Loudness: related to the energy of sound.

Sound Waves  Sound is a longitudinal wave  It requires a medium to convey it, e.g. a gas, liquid, or solid  In a gas, the amplitude of the sound wave.

Doppler Effect Doppler effect- an observable change in frequency. As a moving object approaches an observer the frequency goes up, as is moves away the.

Astrophysics and Cosmology The Wavelengths get “squished” in the direction of motion, and “stretched” in the opposite direction. Doppler Shift Longer,

Waves and Sound Chapter 15 Pages What are waves? Waves are rhythmic disturbances that carry energy through matter or space Waves generally travel.

Sources of Sound  sound is a mechanical wave produced by vibrations that occur in a medium-- generally air  sound is a longitudinal wave.

Goal: To understand sound Objectives: 1)To learn about Sound waves 2)To understand the Speed of sound 3)To learn about Doppler Shifts 4)To learn about.

Doppler Effect Change in frequency when a source of sound is moving relative to an observer. Source of sound moving Source of sound stationary Hears lower.

Diffraction – The bending of a wave around a barrier, such as an obstacle or the edges of an opening.

Sect. 12-6: Sound Wave Interference & Beats Like any other waves, sound waves can interfere with each other. Example Can lead to beats.

 For source moving away from observer, wavelength increases  Following the same procedures gives   For source moving away, f o

Sound and the Doppler Effect. Sound Waves Sound is longitudinal compression wave. Despite this fact, we can still convert and remodel sound waves into.

"I love hearing that lonesome wail of the train whistle as the

Doppler Effect. As a wave source approaches, an observer encounters waves with a higher frequency. As the wave source moves away, an observer encounters.

Doppler Effect David William D. Ecoben III-Archimedes.

Waves. A. What are Waves? - Rhythmic disturbances that carry energy through matter and space. B. Medium - Type of material that waves can pass through.

Sound Waves. Sound is a compressional or longitudinal wave The “wiggle” (compression) is in the same direction as the wave travels.

Physics. Wave and Sound - 5 Session Session Objectives.

Introducing Sound Waves David William D. Ecoben III-Archimedes.

The Doppler Effect Pg 503. Bell Ringer  What do you observe when an ambulance with a flashing siren comes towards you? Away from you? Why?

The Doppler Effect Textbook: 13.5 Homework: pg. 473 # 18, 19 pg. 476 # 64 – 71.

WavesSection 2 Bellringer In the diagram, A is the distance from a point on one wave to an identical point on the next wave. What might this distance be.

The Doppler Effect Introductory Video as a sound source moves towards you it appears to have a higher frequency than normal as the source moves away it.

Today (Finish Chapter 13, Sound)  Temperature and Heat Concepts Tomorrow (Start Chapter 14)  Standing Waves  Beats  Doppler Effect  Example Problems.

Sound and the Doppler Effect. Sound All sounds are produced by the vibrations of material objects They are compressional waves carried by a medium (air,

Doppler Effect A Doppler effect is experienced whenever there is relative motion between a source of waves and an observer. A Doppler effect is experienced.

Characteristics of Waves Chapter 15.2 Notes. Wave Properties There are several wave properties, such as amplitude, wavelength, period, and frequency Amplitude.

Doppler effect Eeeeeee – yowwwwwwwwww A change in frequency or pitch of a sound detected by an observer.

Sound Waves. Sound is a compressional or longitudinal wave The “wiggle” (compression) is in the same direction as the wave travels.

Wave Properties. Amplitude The distance a wave vibrates from its rest position. The distance a wave vibrates from its rest position. The greater the amplitude,

IP Moving wave sources Moving wave sources.

What is the symbol of wavelength? Landa Back to front.

Doppler Effect.

The Doppler Effect THE LAST LECTURE.

Doppler Effect & Shock Waves

Doppler Effect The apparent shift in frequency caused by the movement of the sound source or the movement of the observer. When the waves get crunched.

The Doppler Effect Elvis 8 (1963) Andy Warhol Vocabulary:

Doppler Effect Doppler Effect – The apparent change in frequency of a wave due to the motion of the source and/or the observer Stationary Source – Moving.

Speed Formula - Waves.

Doppler Effect and Red/blue Shift

1. Doppler Effect Change in frequency of a wave due to relative motion between source and observer. A sound wave frequency change is noticed as a change.

Doppler Effect - By Jemma and Ruby

Doppler effect Eeeeeee – yowwwwwwwwww

Harmonic Motion and Mechanical Waves

11: Wave Phenomena 11.2 The Doppler Effect.

24.2 Speed of Waves.

Doppler Effect.

Doppler Effect.

Doppler effect Eeeeeee – yowwwwwwwwww

Doppler Effect Christian Doppler.

Presentation transcript:

CHAPTER 14 Sound Doppler Effect A train passes by you with its whistle/horn blowing. You hear one pitch (tone) as the train is coming towards you and a different pitch after the train has passed you. Why?

Qualitative Explanation Sound waves travel at about 343 m/s regardless if the source is moving or not. They are not like a ball thrown at 40m/s off the front of a train which would have a ground velocity of 40m/s + train velocity. Train speed is not orders of magnitude different from the speed of sound. Movement of the train causes wave crests to “bunch up” in front of the train (higher pitch) and spread out (lower pitch) behind the train.

Doppler Quantitative Explanation Speed of sound: v = 343 m/s Velocity of source: v s Frequency of source: f Period of source: T Wavelength of source: Observer “A” Perspective Apparent wavelength = ’ = - distance source moved during one wave period ’ = - v s T ’ = - v s f Apparent frequency: f’ = f’ = f v ’ ( ) v v - v s ; v = f’ ’ ; ’ = - v s f

Speed of sound: v = 343 m/s Velocity of source: v s Frequency of source: f Period of source: T Wavelength of source: Observer “B” Perspective Apparent wavelength = ’ = + distance source moved during one wave period ’ = + v s T ’ = + v s f Apparent frequency: f’ = f’ = f v ’ ( ) v v + v s

Doppler Effect with Receptor (You!) Moving Moving Receptor: Apparent velocity of sound is important v’ = v + v o where v o = receptor velocity and where receptor “chasing” source v’ = v – v o where receptor avoiding source One Equation f’ = f ( ) v  v o v v s 

Example Problem Example Problem (Doppler Effect) The siren of a police car at rest emits a sound with a frequency of 1600Hz (Hertz). What frequency will you hear if the police car moves at 25.0 m/s a) towards you? b) away from you? Which sounds worse? a) f’ = f ( ) v  v o v v s  f = 1600 sec -1 v = 343 m/s v s = 25.0 m/s v o = 0.0 m/s f’ = ( ) ( ) 343m/s 343 m/s – 25.0 m/s f’ = 1726 sec -1 = 1726 Hz b) f’ = (1600 sec -1 ) ( ) 343m/s 343 m/s m/s f’= 1491 sec -1 = 1491 Hz c) Police sirens always sound worse when they are… moving towards you!!