TRANSVERSE AND LONGITUDINAL WAVES
By Hal Fox
TRANSVERSE AND LONGITUDINAL WAVES
A short tutorial by Hal Fox
You are going to hear a lot more about transverse and longitudinal electromagnetic waves. Here is one way to understand the difference by an analogy. Walk out into the ocean until the water is up to your waist, hopefully far enough away from the beach so that there is no strong surging of the surf back and forth.
The waves that are coming toward the beach and breaking on the shore are transverse waves. You can think of these waves as traversing long distances. Key memory words transverse = traverse. These waves could carry information. If at some distance you had a machine that would make waves and you could change the wave pattern using your machine, then you could send a simple code and carry such coded information over some distances.
So it is with electromagnetic waves (radio or television waves). These transverse waves are modulated or encoded with information. Originally called Hertzian waves and using start and stop coding (like the telegraph dots and dashes), these Hertzian waves were the forerunners of our radio (later television) communications. These are the electromagnetic waves that most people know about.
Now back to the ocean. You are standing in the ocean water up to your waist. You notice that the water moves up and down your body as the waves pass by you. However, that piece of seaweed or a floating cork (if you take one with you) does not move toward the shore nor travel with the waves. You can then talk about the wave moving up and down your waist as the longitudinal wave. It has energy. If you were to put a float there, you could extract energy from the wave motion that moves the float up and down. That float would be tapping the energy of the longitudinal wave.
Tom Bearden waxes eloquent about longitudinal waves, time, and energy. In our forthcoming conference - INE-99 Symposium - you are going to hear more about transverse and longitudinal waves. Perhaps it will help your thinking to visualize the ocean waves in the way described to keep in mind the difference between transverse and longitudinal waves.
www.padrak.com/ine/NEN_6_11_4.html
Sept., 1999.