doppler effect

简明释义

多普勒效应

英英释义

例句

1.The doppler effect explains why the pitch of a siren sounds higher as it approaches and lower as it moves away.

多普勒效应解释了为什么警报声在接近时听起来更高，而远离时则听起来更低。

2.Astronomers use the doppler effect to determine the speed of stars moving away from Earth.

天文学家利用多普勒效应来确定远离地球的星星的速度。

3.The sound of a passing ambulance changes pitch due to the doppler effect.

由于多普勒效应，经过的救护车的声音音调发生了变化。

4.When a train approaches, you can hear the sound change because of the doppler effect.

当火车靠近时，你可以听到声音的变化，这就是多普勒效应。

5.In medical imaging, the doppler effect is used to measure blood flow.

在医学成像中，多普勒效应用于测量血流。

作文

The Doppler effect is a fascinating phenomenon that occurs when there is a relative motion between a source of waves and an observer. This effect is most commonly associated with sound waves, but it also applies to light waves and other types of electromagnetic radiation. Understanding the Doppler effect is crucial in various fields, including astronomy, radar technology, and even everyday experiences such as hearing a passing ambulance. To illustrate the Doppler effect, imagine standing on the sidewalk as an ambulance approaches with its siren wailing. As the ambulance moves towards you, the sound waves are compressed, resulting in a higher pitch. This is because the sound waves are being emitted from the moving source at a faster rate than they are reaching you. Once the ambulance passes and begins to move away, the sound waves are stretched out, leading to a lower pitch. This change in frequency is the essence of the Doppler effect. In scientific terms, the Doppler effect can be described mathematically. The frequency of the waves received by the observer can be calculated using the formula: f' = f (v + vo) / (v + vs), where f' is the observed frequency, f is the source frequency, v is the speed of waves in the medium, vo is the speed of the observer relative to the medium, and vs is the speed of the source relative to the medium. This equation helps us quantify how the frequency of waves changes based on the relative motion of the source and the observer. The implications of the Doppler effect extend far beyond just sound. In astronomy, for example, scientists use this effect to determine the movement of stars and galaxies. When a star is moving towards Earth, its light waves are compressed, causing a shift towards the blue end of the spectrum, known as blue shift. Conversely, if a star is moving away, its light waves are stretched, resulting in a red shift. By analyzing these shifts, astronomers can infer the speed and direction of celestial bodies, providing invaluable information about the universe. Moreover, the Doppler effect plays a critical role in radar and medical imaging technologies. In radar systems, the change in frequency of the reflected waves can indicate the speed of an object, such as a car or an aircraft. Similarly, in medical ultrasound, the Doppler effect is used to measure blood flow and detect abnormalities in the heart or blood vessels. In conclusion, the Doppler effect is a remarkable phenomenon that illustrates the relationship between motion and wave frequency. Its applications are vast and varied, impacting our understanding of the universe and enhancing technologies in our daily lives. By grasping the concept of the Doppler effect, we gain insight into not only the mechanics of sound and light but also the fundamental principles that govern the natural world around us.

多普勒效应是一个迷人的现象，当波源与观察者之间存在相对运动时，就会发生这种效应。这个效应最常与声波相关，但它也适用于光波和其他类型的电磁辐射。理解多普勒效应在各个领域都是至关重要的，包括天文学、雷达技术，甚至日常生活中的一些体验，比如听到经过的救护车。为了说明多普勒效应，想象一下你站在人行道上，救护车带着尖锐的警报声驶来。当救护车朝你驶来时，声波被压缩，从而导致音调升高。这是因为从移动源发出的声波以比到达你的速度更快的速率发出。一旦救护车经过并开始远离，声波被拉伸，导致音调降低。这种频率的变化就是多普勒效应的本质。在科学术语中，多普勒效应可以用数学公式描述。观察者接收到的波频率可以使用以下公式计算：f' = f (v + vo) / (v + vs)，其中f'是观察到的频率，f是源频率，v是媒介中波的传播速度，vo是观察者相对于媒介的速度，vs是源相对于媒介的速度。这个方程帮助我们量化频率如何根据源和观察者的相对运动而变化。多普勒效应的影响远远超出了声音。在天文学中，例如，科学家们利用这一效应来确定恒星和星系的运动。当一颗星星朝地球移动时，它的光波被压缩，导致光谱向蓝色端偏移，这被称为蓝移。相反，如果一颗星星远离，它的光波被拉伸，导致红移。通过分析这些偏移，天文学家可以推断天体的速度和方向，从而提供关于宇宙的宝贵信息。此外，多普勒效应在雷达和医学成像技术中也发挥着关键作用。在雷达系统中，反射波频率的变化可以指示物体的速度，例如汽车或飞机。同样，在医学超声中，多普勒效应用于测量血流并检测心脏或血管的异常。总之，多普勒效应是一个了不起的现象，它展示了运动与波频率之间的关系。它的应用广泛而多样，影响着我们对宇宙的理解，并增强了我们日常生活中的技术。通过掌握多普勒效应的概念，我们不仅能够深入了解声音和光的机制，还能够理解支配我们周围自然世界的基本原理。