Doppler Effect

Hello All!

As promised, I have included a discussion on the Doppler Effect for those who are unfamiliar with it. It may look (yawn!) very boring at the beginning, but keep reading… IT GETS REALLY GOOD! ENJOY!

Doppler Effect

         I always thought that the Doppler Effect was a common topic discussed at dinner time. What is the Doppler effect? Well it concerns both sound and light vibrations; something that physicists work with on a daily basis. One  Austrian physicist named Christian Doppler noticed that as trains approached him, the sound had a high pitch. But as the train went by him the sound pitch lowered. So after some intense theorizing, mathematics, and tests he came up with a law called the Doppler Effect. The Doppler Effect is defined as such: The apparent difference between the frequency at which sound or light waves leave a source and that at which they reach an observer, caused by relative motion of the observer and the wave source. So in short, as an object is approaching you, the light and sound waves are at a higher frequency. As an object is moving away from you, the light and sound waves shift to a lower frequency.

      The following is an example of the Doppler effect: as one approaches a blowing horn, the perceived pitch is higher until the horn is reached and then becomes lower as the horn is passed. Similarly, the light from a star, observed from the Earth, shifts toward the red end of the spectrum (lower frequency or longer wavelength) if the Earth and star are receding from each other and toward the violet (higher frequency or shorter wavelength) if they are approaching each other. The Doppler effect is used in studying the motion of stars and to search for double stars and is an integral part of modern theories of the universe. 

So go ahead! Talk about sound and light waves and the effect of Doppler shift at your dinner table. You will find that the conversation will go on for hours past your bed time. Your children will not sleep because of their nightmares about sound waves. You will be unable to perform in bed for your spouse because you keep thinking about sound and light waves. For weeks you will be unproductive at your job because you keep thinking about the Doppler Effect. Dinner time will become a nerve wrenching experience:

FATHER: “Please don’t anyone talk about those damn sound waves! They make me so nervous!”

MOTHER: “Honey, maybe you should stop thinking about them. You obsess over the silliest things!”

DAUGHTER: “Daddy, please don’t talk about those light waves again. They scare me.”

MOTHER: “She hasn’t had a decent nights sleep in weeks. What do you expect when you keep her up for hours fretting over such silly things liked sound waves. And when she does sleep she gets nightmares about you and sound and light…”

FATHER: (now on the verge of terror): “Damn it! (starts to shout) I TOLD YOU NOT TO TALK ABOUT THOSE WRETCHED SOUND AND LIGHT WAVES. FOR WEEKS THAT’S ALL I’VE BEEN THINKING ABOUT AND TALKING ABOUT! HOW DO YOU THINK IT MAKES ME FEEL KNOWING THAT I AM GETTING BOMBARDED WITH LIGHT AND SOUND! I’M HAVING A NERVOUS BREAK DOWN!!!!!!!!!!!!!!!!!!!!”

DAUGHTER: (starting to cry) “No Daddy! No!”

Your wife will have enough and will decide to have you committed for your own personal safety.

So go ahead. Keep thinking about those light and sound waves and how the Doppler Effect crunches them. It will drive you mad. It will give you a nervous break down!