The Doppler effect or Doppler shift is the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source. This phenomenon was described by an Austrian physicist named Christian Doppler in 1842. It is caused by the change in distance between the thing creating the wave (the causer) and whatever is measuring seeing or hearing the wave (the observer).
 |
| Christian Doppler |
If
the observer and the creator of the wave get closer, the frequency is
higher and the wavelength is shorter. For light, this causes a shift
in color towards the blue end of the spectrum, called a blue shift.
The faster something is moving towards us, the greater the blue
shift. For sound, this causes the sound to become higher in pitch.
If
the distance between the observer and the creator gets longer, the
frequency is lower and the wavelength is longer. For light, this
causes a shift towards the red end of the spectrum, called a red
shift. The faster something is moving away from us, the greater the
red shift. For sound, this causes the sound to become lower in pitch.
Comments
Post a Comment