Doppler Effect The Doppler Effect is the change in the observed frequency caused by the motion of the wave source.

Slides:



Advertisements
Similar presentations
GCSE Notes: LOJ: April 2004 Red Shift GCSE Level Notes.
Advertisements

David - Doppler He is known for the principle he proposed he first proposed in concerning the colored light of double stars in He hypothesized that.
The Doppler Effect Astrophysics Lesson 15. Learning Objectives To know:-  What the Doppler Effect is.  What is meant by the term ‘redshift’.  How to.
The Doppler Effect Refers to the frequency change in waves as objects move toward you or away from you. As things move toward you – waves become compressed,
1 Hydrogen in the Milky Way Hydrogen is the most abundant element in our galaxy. The 21-cm Line.
The Doppler Effect.
Electromagnetic Radiation Electromagnetic radiation - all E-M waves travel at c = 3 x 10 8 m/s. (Slower in water, glass, etc) Speed of light is independent.
Spectral analysis of starlight can tell us about: composition (by matching spectra). temperature (compare to blackbody curve). (line-of-sight) velocity.
Doppler Effect.
The Doppler Shift Brought to you by McCourty-Rideout enterprises- tuned into your frequency.
How do we really know what's out there? Space is a pretty big place and, after all, we've never been farther from earth than our moon. How do we know.
The Doppler Effect Thursday, October 26, First, a review from yesterday…
The Doppler Effect. Doppler Effect & Sound Christian Doppler Observing the Doppler Effect Christian Doppler Observing the Doppler Effect Christian Doppler.
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.
Section  The Doppler Effect: A change in frequency (pitch) due to relative motion between a source of sound and its observer.
Doppler Effect The Doppler effect is the apparent change in the frequency of a wave motion when there is relative motion between the source of the waves.
Doppler Shift October 19, 2009.
Before the bell rings, in your notes, write out the important aspects of a correctly designed experiment. Make sure to include a description of your variable.
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.
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,
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.
The Doppler Effect.
IP Light and the doppler effect © Oxford University Press 2011 Light and the doppler effect.
Electromagnetic Spectrum
How do we really know what's out there? Space is a pretty big place and, after all, we've never been farther from earth than our moon. How do we know.
Physics 1 Revision Lesson 6 Sound and the Red shift.
The Doppler Effect.
What is the DOPPLER EFFECT? Doppler and Sound  When sound waves are made they spread out evenly in all directions like ripples on a pool of water 
Wave Phenomena Characteristics of Waves What is a wave? G A wave is a vibratory disturbance through a material (medium) or space G Waves transfer ENERGY.
How do we really know what's out there? Space is a pretty big place and, after all, we've never been farther from earth than our moon. How do we know.
How do we really know what's out there? Space is a pretty big place and, after all, we've never been farther from earth than our moon. How do we know what.
Waves. The time it takes for one wavelength to pass is called the period. The number of wavelengths passing at a given time is called frequency.
How do we know our Universe is expanding?. Throughout our universe, light is bursting from stars, bouncing off planets, diving into black holes, wandering.
An Expanding Universe Redshift, Blueshift and the Doppler Effect.
Red Shift – Expanding Universe 5 a day. 1. If a star or galaxy is moving away from us, its wavelength will shift which way? 2. If a star or galaxy is.
11: Wave Phenomena 11.2 The Doppler Effect. The Doppler Effect When a car passes you on the street, the frequency of its engine note appears to change.
THE BIG BANG THEORY The Expanding Universe. Review Human demonstration.
Doppler Effect David William D. Ecoben III-Archimedes.
The Doppler Effect. Shown by all types of waves Properties of Waves Waves are characterized by two numbers: Wavelength,  (size of the wave) Frequency,
The Doppler Effect The sound of a police car siren changes as it moves past you. The pitch of the siren seems to change. Ahead of the car, the sound waves.
The Expanding Universe Additional reading: Higher Physics for CfE, p Notes p.42 Watch or listen to the following video clips:
Opening Activity Pick a seat… let’s stay in that seat for a couple of weeks. Pre-Assessment What do you know about the Big Bang Theory? Aug 25.
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.
Test Prompt Pre-Assessment What do you know about the Big Bang Theory? Jan 14.
Key Areas covered The Doppler effect is observed in sound and light The Doppler effect causes shifts in wavelengths of sound and light The light from objects.
Key Areas covered The Doppler effect is observed in sound and light The Doppler effect causes shifts in wavelengths of sound and light.
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.
Doppler Effect Shift in frequency (high to low) due to the compression of light (or sound) waves in front of a moving object and the expansion of the light.
Large-Scale Structure in the Universe Superclusters, walls, and voids dominate the large scale structure of the Universe.
 You will know the Doppler effect as the falling note of a car or train horn as it approaches, passes, and then goes away from you.
IP Moving wave sources Moving wave sources.
How do we really know what's out there?
Doppler Effect and Redshift
The Doppler Effect Elvis 8 (1963) Andy Warhol Vocabulary:
Earth Science With Mr. Thomas.
III.) Doppler Effect: an observed change in the frequency of a wave when the source or observer is moving A) Pitch of a sound (how high or low it is) is.
Doppler Effect.
Title: 30.1 Galaxies and The Universe
Doppler Effect.
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
Star Light The spectrum of light a star emits can tell us what type of atom is present both inside the core and in its atmosphere. The pattern of dark.
Red Shift & Blue Shift.
Doppler Effect Waves and Sound
11: Wave Phenomena 11.2 The Doppler Effect.
1. Review: what are the parameters of a wave?
Spectral analysis of starlight can tell us about:
Topic 3 – Part III The Doppler Effect
Presentation transcript:

Doppler Effect

The Doppler Effect is the change in the observed frequency caused by the motion of the wave source.

Click to start

Key Idea to remember, is that the wave speed doesn’t depend on source speed. (This is not obvious!!) Ball: 10ms -1 CAR: 20ms -1 Ball: 10ms -1 How fast is the ball relative to Emma?

Sound waves don’t do the same thing! CAR: 20ms -1 SOUND: 340ms -1 Emma measures the same wave speed whatever direction the car is moving.

Stationary Source of Waves What do you notice about the wavelength at any point? What do you notice about the frequency at any point?

Moving Source What do you notice about the wavelength at any point? What do you notice about the frequency at any point?

Stationary SourceMoving Source Wavelength the same in all directions Longer Wavelength Shorter Wavelength Normal Wavelength

When the source is approaching, the perceived wavelength is shorter The wave speed is the same The perceived frequency ishigher

When the source is moving away, the perceived wavelength is longer The wave speed isthe same The perceived frequency is lower

link to simulation

Doppler Equation The wavelength when the source is stationary is The wavelength in front of the source is The source frequency is f The perceived frequency is f’

Extension

The Doppler Equation is: The denominator is v w -v s if the source is moving towards the observor The denominator is v w -v s if the source is moving away from the observor

Accelerating Source If the source accelerates towards you, the source speed gets gradually the wavelength gets gradually So the frequency gets gradually If the source accelerates away fom you, the wavelength gets gradually So the frequency gets gradually shorter higher longer lower higher

Sketch a graph of frequency v time for the observer as the car passes Constant velocity frequency time

Sketch a graph of frequency v time for the observer as the car passes accelerating frequency time

Off line Observer Sketch a graph of frequency v time for Fleur FLEUR

Off line Observer What happens if Fleur is off line? FLEUR link to simulation

Sketch a graph of frequency v time for Fleur

In this equation, v s is the speed the source is approaching, not moving

Doppler Duck

Red Shift Until about 1940, it was thought that the universe was static. Hot objects emit a continuous spectrum. When this light passes through a Hydrogen gas, you get an absorption spectrum. These are dark lines at certain wavelengths

Hydrogen Absorption Spectrum as viewed in Earth Laboratory Hydrogen Absorption Spectrum viewed from a Star What do you notice about the spectrum of light from the star? The same spectrum reaches us, but the absorption lines are red shifted. This means the light has a longer wavelength.

What does this show? This shows the galaxies are moving away from us. This shows that the universe is………… EXPANDING STAR EARTH