Here's a breakdown:
* Doppler effect: This is the change in frequency or wavelength of a wave for an observer who is moving relative to the source of the wave.
* Moving towards the source: The frequency of the wave appears higher (higher pitch for sound, bluer light for light waves).
* Moving away from the source: The frequency of the wave appears lower (lower pitch for sound, redder light for light waves).
Examples of the Doppler effect:
* Sound: The pitch of a siren changes as an ambulance passes you.
* Light: Stars moving towards us appear slightly bluer, while those moving away appear slightly redder.
* Radar: Police use the Doppler effect to measure the speed of vehicles.
