Slight change in pitch noted when one moves rapidly toward or away from a sound source (or when the latter moves toward or away from the ear). Upon approach, the pitch sounds a little higher; when receding, a little lower.
When the source of a sound is moving relative to the listener, the frequency heard by the listener is different than the frequency at the source. When the sound is approaching the listener, the frequency is higher--when the sound is moving away, the frequency is lower. An example would be the aproach and passing by of a train whistle while sitting at the gate. As the train approaches, the whistle is heard as a high pitch, yet once the train passes, the pitch decreases.
The Doppler effect occurs whenever a source of light or sound waves moves with respect to the observer, and results in a change in the wavelength and frequency of the waves. Sound waves are "pressed together" when the source of the sound approaches and "stretched out" when the source of the sound moves away. It was named for J. Christian Doppler, an Austrian physicist, who in 1842 explained why the whistle of an approaching train had a higher pitch than the same whistle when the train was going away. The MDI instrument records small periodic changes in the wavelength of light, measuring the oscillation speeds on the Sun using the Doppler effect.
an effect in which the frequency of light or sound coming moving object is different when it is received compared to when it was emitted. How much the frequency changes depends on how fast the object is moving toward or away from the receiver. (See also the text in doppler and Spec.)
The shift in wavelength of light that is caused by relative motion between the source of light and the observer. The Doppler shift, Deltagamma, is defined as the difference between the observed and rest (laboratory) wavelengths for a given spectral line.
Apparent shift in wavelength or frequency as a result of relative line-of-sight motion between the observer and the source of radiation.
Same as Doppler shift. The change in frequency with which energy reaches a receiver when the receiver and the the energy source are in motion relative to each other.
The perceived change in the frequency of a sound caused by motion of the listener relative to the source of the sound.
Any motion-induced change in the observed wavelength (or frequency) of a wave.
The process by which light or sound is altered in perceived frequency or wavelength by the motion of its source with respect to the observer. This is a key component in determining redshift.
A change in the apparent frequency (or wavelength) of a wave as observer and source move toward or away from each other. The effect is found with sound waves: as the source and observer move together the apparent frequency of the sound is higher than that produced; as they move apart it is lower. For example, an approaching motorbike -- the pitch of the engine sound appears to drop suddenly as it passes. A similar effect is observed in electromagnetic radiation (light). The radiation emitted by a source moving rapidly towards the observer will have increased frequency and a smaller wavelength. If the source is moving away from the observer, the observed frequency is reduced, and the wavelength is "stretched." Movement toward the observer results in a blueshift; movement away from the observer results in a redshift. This has great significance in astronomy.
A change in the wavelength of spectral lines caused by a motion towards or away from the observer. Motion toward the observer reduces the wavelengths of the spectral lines, whereas motion away from the observer increases the wavelengths.
The change observed in the frequency with which a wave from a given source reaches an observer when the source and the observer are in relative motion.
An observer receives sound and light from bodies moving away from her with lower frequency and longer wavelength than emitted (see Redshift) and from bodies moving toward her with higher frequency and shorter wavelength. The shift in frequency increases as the speed of the body increases.
The apparent change in the observed frequency of a wave as a result of relative motion between the source and the observer.
(Doppler Shift)- A shift in an object's sound due to motion. If an object is moving towards you, the sound waves will get squished together and will have a higher pitch. If it is moving away, the sound waves will get spread out and have a lower pitch.
the apparent change in frequency of a moving body relative to a reverence point.
the result of frequencies of waves being observed differently because of the observer's reference frame
The apparent shift in frequency of an incident wave that is the result of relative velocity between the emitter of the wave and the receiver of the wave. The Doppler shift frequency (fd) is given by: fd = 2 V (f0 / c) cosF, where: f0 is transmitter frequency in Hz, c is velocity of light (3 x 108 meters per second), V is the magnitude of the relative velocity (meters per second), æ is the angle between the incident wave and target's path. Note: cos æ is 1 for motion directly toward or away from the receiver. Velocity (V) is a vector that determines the sign of doppler shift frequency.
The apparent change in the frequency of a note due to the relative motion between the source of the note and the observer.
The observed shift in wavelength or frequency as a result of relative radial motion.
The change in the frequency of a wave, as a light wave or sound wave, resulting from relative motion of the source and the receiver.
A change in the observed frequency of electromagnetic or other waves caused by the relative motion between the source and the observer.
If an electromagnetic source moves relative to an observer, there is a shift in the observed frequency. Also known as Red Shift, if the source is receding from the observer, the observed frequency will appear to decrease.
Apparent change in wavelength of the radiation from a source due to its relative motion away from or towards the observer.
A phenomenon in which waves appear to compress as their source approaches the observer or stretch out as the source recedes from the observer.
The apparent change in the wavelength of waves due to the relative movement of the source of the waves relative to the observer.
Change in frequency of an electromagnetic or sound wave resulting from differential movement, for example, raindrops moving towards a Doppler radar will cause the reflected microwave beam to move towards higher frequency, enabling calculation of the raindrop speed.
Relationship between wavelength and speed where shifting of wavelength occurs when the movement of an object is away or towards an observer.
the change in wavelength observed when a body emitting light is moving toward (blue shift) or away (red shift) from an observer.
The apparent change in frequency of sound or light waves, varying with the relative velocity of the source and the observer. If the source and observer draw closer together, the frequency is increased. Named for Christian Doppler, Austrian mathematician and physicist (1803-1853).
The apparent difference between the frequency at which sound or light waves leave a source and that at which they reach an observer, caused by relative motion of the observer and the wave source.
The phenomenon in which the frequency of wave energy appears to change when a moving source of wave energy passes an observer.
The change in frequency of a sound wave due to the relative motion between a sound source and listener. For example, when a car moves past you while sounding its horn, you will hear a drop in pitch as the car passes.
The change in the observed frequency of an acoustic or electromagnetic wave due to relative motion of the source and the receiver. (Basic Science/sound/dopplereffect.htm)
The Doppler effect is the change in pitch that occurs when a sound has a velocity relative to the listener. When a sound moves towards the listener the pitch will rise. when going away from the listener the pitch will drop. A well known example is the sound of an ambulance passing by.
A change in the frequency of light or sound waves due to the relative movement between the source and the observer
A change in the wavelength of radiation due to relative radial motion of the source and the observer.
A measurable shift in the wavelength of a traveling wave caused by the relative motion of the source and observer. If a source and observer are approaching each other, the wavelength of incoming light is shifted to shorter, or bluer, wavelengths; if a source and observer are receding from each other, the wavelength of incoming light is shifted to longer, or redder, wavelengths. Stars with relative motion toward an astronomer appear bluer than they would otherwise, i.e. the entire spectrum of star light shifts toward the blue end of the spectrum or is blue-shifted. Stars speeding away from the astronomer appear redder than they would otherwise, i.e. the entire spectrum is red-shifted. The expansion of the universe can be detected because the farther away a celestial object is from the Earth, the more it tends to be red-shifted. See also blue shift red shift
change in frequency caused by relative motion between sound source and a listener (see figure 15.11)
The apparent change in wavelength of sound or light caused by the motion of the source, observer or both.
A change in reflected frequency caused by reflector motion. If the media boundary (reflector) is moving toward the source the reflected frequency will be higher than the incident frequency. If the reflector is moving away from the source the reflected frequency will be lower than the incident frequency.
an apparent change in the wavelength of energy produced by an object that is caused by the object's motion towards or away from the observer (along the line of sight). In astronomical spectra, the doppler effect is seen in the shifting of spectral lines.
The apparent change in the wavelength (or frequency) of a wave, caused by line-of-sight motion of the source or of the observer (or both).
The change in the wavelength of sound or light waves caused when the object emitting the waves moves toward or away from the observer; also called Doppler Shift. In sound, the Doppler Effect causes a shift in sound frequency or pitch (for example, the change in pitch noted as an ambulance passes). In light, an object's visible color is altered and its spectrum is shifted toward the blue region of the spectrum for objects moving toward the observer and toward the red for objects moving away.
An apparent shift in the frequency of a wave. For example, when someone is listening to the sound of an ambulance siren, and that person is staying still but the ambulance is driving by, the person will hear a change in pitch of the ambulance siren. That change in pitch is caused by the doppler effect. The frequency of a sound wave determines the pitch, and the distance of the source of the sound from the sound's observer determines the amount that the frequency seems to have shifted, known as the doppler shift.
The apparent change in frequency or pitch when a sound source moves either toward or away from a listener. In radar, the change in frequency of a received signal caused by the relative motion between the radar and the target.
the change in frequency (or wavelength) produced when a moving source generates waves.
The Doppler effect, named after Christian Doppler, is the apparent change in frequency and wavelength of a wave that is perceived by an observer moving relative to the source of the waves. For waves, such as sound waves, that propagate in a wave medium, the velocity of the observer and of the source are reckoned relative to the medium in which the waves are transmitted. The total Doppler effect may therefore result from either motion of the source or motion of the observer.