N: 1. Doppler effect is an eponymous created form the Austrian mathematician and physicist Christian Doppler (1803 – 1853)
2. Because the speed of sound depends only on the state of the gas, some interesting physical phenomena occur when a sound source moves through a uniform gas. You can study some of these phenomena by using the interactive sound wave simulator. As the source moves it continues to generate sound waves which move at the speed of sound. Since the source is moving slower than the speed of sound, the waves move out away from the source. Upstream (in the direction of the motion), the waves bunch up and the wavelength decreases. Downstream, the waves spread out and the wavelength increases. The sound that our ear detects will change in pitch as the object passes. This change in pitch is called a doppler effect. There are equations that describe the doppler effect. As the moving source approaches our ear, the wavelength is shorter, the frequency is higher and we hear a higher pitch.
3. Because Doppler is used to measure changes in sound waves, it is used to diagnose conditions related to circulation and blood flow. The Doppler ultrasound can actually measure how fast or slow blood is moving, which can indicate a circulatory problem. Blood clots can be found using Doppler ultrasound because the ultrasound will be able to detect slower blood flow or a lack of blood flow where the clot is located. Doppler ultrasound can also be used to identify narrowed arteries, plaque buildup in the blood vessels, or blocked arteries. Found early, many of these conditions can be treated before they become more serious.
4. The Doppler effect is of intense interest to astronomers who use the information about the shift in frequency of electromagnetic waves produced by moving stars in our galaxy and beyond in order to derive information about those stars and galaxies.
5. Cultural Interrelation:
- Reality: The book Doppler effect by John Kinsella, talks about the Doppler effect.
- Fiction: The TV serie The Big Bang Theory, in the first season. Chapter number 6 The Middle Earth Paradigm, where Sheldon Cooper appears with a costume of the Doppler effect and he explain what it is.
S: 1. Biography – https://goo.gl/8FZL6N (last access: 9 November 2016). 2. Nasa – https://goo.gl/y38E53 (last access: 9 November 2016). 3 Brighthub – https://goo.gl/uzjUWb (last access: 9 November 2016). 4. PCR – https://goo.gl/wtUHXi (last access: 4 November 2016). 5 Goodreads – https://goo.gl/HQFI7F (last access: 9 November 2016); CBS – https://goo.gl/RHZ8BA (last access: 9 November 2016).