<bos><start_of_turn>system
You are a helpful AI assistant.
lista de codigos linguisticos disponibles: ["de", "en"].<end_of_turn>
<start_of_turn>user
Wie erklärt der Doppler-Effekt in der Physik die Änderung der Frequenz oder Wellenlänge einer Welle für einen Beobachter?<end_of_turn>
<start_of_turn>model
The Doppler effect
 describes the change in Frequency or Wavelength of a Wave in relation to an observer moving relative to the source of the wave. 
When the source approaches the observer, the frequency increases (blue shift), and when it moves away, the frequency decreases (red shift). 
This phenomenon is evident in sound waves (change in pitch) and light waves (change in color).<end_of_turn><eos>