doppler effect
doppler effect — 名詞
1. The way sound or light waves appear to change in pitch or color to a person when
都卜勒效應
移動的波源使聲光聽起來或看起來不同的現象
The way sound or light waves appear to change in pitch or color to a person when the object producing the waves moves either toward or away from that person.
An ambulance siren sounds higher as it comes closer and lower after it passes due to the Doppler effect.
救護車警笛聲在靠近時聽起來較高，遠離後變得較低，這是都卜勒效應造成的。
illustrates pitch change with approaching then receding source
A train horn drops in pitch as the train rushes past — a familiar example of the Doppler effect.
火車鳴笛聲在列車呼嘯而過時會變低——這是都卜勒效應的一個常見例子。
Police radar guns use the Doppler effect to calculate a car's speed from reflected radio waves.
警用雷達槍利用都卜勒效應，從反射的無線電波計算車速。
An ice cream truck's music changes pitch as it approaches and passes — the Doppler effect.
冰淇淋車的音樂在靠近和經過時會改變音高——這就是都卜勒效應。
A racing car's roar sounds higher as it speeds toward you and deeper as it passes, showing the Doppler effect.
賽車的轟鳴聲在衝向你時聽起來較高亢，駛過後變得較低沉，顯示了都卜勒效應。
文法句型
the Doppler effect (noun phrase)
Doppler effect + in + {sound, light, waves}
用法筆記
Frequently used with the definite article: 'the Doppler effect.' In everyday speech it is most often used to explain why the pitch of a siren, horn, or engine changes as a vehicle passes by.
常見錯誤
2. The measurable change in the frequency of waves (such as sound, light, or radio)
都卜勒頻移
波源相對運動造成的波動頻率改變
The measurable change in the frequency of waves (such as sound, light, or radio) reaching an observer, caused by the movement of the wave source relative to the observer — the frequency rises as the distance shrinks and drops as the distance grows.
Astronomers detect distant planets by measuring the tiny Doppler shift in a star's light.
天文學家透過測量恆星光線中微小的都卜勒頻移來探測遙遠的行星。
collocation: Doppler shift in [star's light / radio waves]
Weather forecasters use Doppler radar to track rain clouds by measuring frequency changes in reflected radio waves.
氣象預報員利用都卜勒雷達，透過測量反射無線電波的頻率變化來追蹤雨雲。
Doppler + noun: Doppler radar, Doppler ultrasound
A technician used Doppler ultrasound to measure blood flow through a damaged vein.
技術人員使用都卜勒超音波來測量血液流經受損靜脈的速度。
A teacher swung a buzzer on a rope so the class heard the Doppler effect in action.
老師將蜂鳴器綁在繩子上甩動，讓全班同學聽見都卜勒效應的作用。
A fire truck's siren pitch falls as it passes because the sound waves stretch out.
消防車經過時警笛音調下降，因為聲波被拉長。
- Doppler shift
Often used interchangeably in physics; 'Doppler shift' emphasizes the measurable frequency change while 'Doppler effect' refers to the broader phenomenon.
文法句型
the Doppler effect (noun phrase)
Doppler shift in + {light, sound, radio waves}
用法筆記
This sense is the formal physics definition. Distinguish from sense 1 (SOUND/LIGHT CHANGE): sense 1 describes what a person observes in daily life, while sense 2 focuses on the measurable wave-frequency shift that underlies the phenomenon. Scientists often use 'Doppler shift' to refer specifically to the frequency change itself.