Pages: (1)_(2)_(3)_(4)_(5)_(6)_(7)_(8)_(9) (10) (11) (Communicating) (Soundwaves) (Life at Western Electric)

What sound waves look like and how they act

Here's what sound waves look like. The caption reads, "A visible pattern of sound waves. This new technique of studying sound demonstrates the focusing effect of an acoustical lens on sound waves issuing from the horn at extreme left. Wave pattern is produced by a scanning technique . . ." Bell Telephone Laboratories (external link) photograph, from the book The First Book of Sound: A Basic Guide to the Science of Acoustics by David C. Knight, Franklin Watts, Inc. New York (1960). p. 80

Sound waves are acoustic waves, with no electrical component. They are simply vibrations in the air, a physical pressure made by the utterance of the speaker.

In somewhat challenging yet elegant writing, A.T.&T. once described sound in these terms, "Audible sound is thus defined as a disturbance in the atmosphere whereby a form of wave motion is propagated from some source at a velocity of 1,075 feet per second, the transmission being accomplished by alternating condensations and rarefacations of the atmosphere in cycles having a fundamental frequency ranging somewhere between 16 per second and 32,000 per second." Principles of Electricity applied to Telephone and Telegraph Work, American Telephone and Telegraph. C.F. Myers, Supervisor of Instruction. Murray Hills, New Jersey? 1939. p.66

Waves are matter

I write a great deal about sound and radio waves at this site, I've even discussed light waves in passing. But did you know that all matter is a wave? A never ending ocean of waves, one after the other, endlessly rolling outward. We usually think of matter as particles; electrons, photons, atoms, somewhat solid forms. But matter as a wave? Actually, matter can be a particle and a wave at the same time. Prince Louis de Broglie (external link) (1892-1987), postulated in 1923 that atoms and their associates constituted solid form and also acted as waves of radiated energy. Although the work of Max Planck and Einstein helped Broglie develop his theory, at the time he advanced his idea there was absolutely no physical evidence to support it. Acceptance and confirmation by others came quickly, however, and in 1929 he was awarded the Nobel Prize. As Martin Mann explains the photograph below, "Electrons, passing through a crystal, make a pattern almost exactly like a light beam. Only waves can interact with each other to produce such patterns; streams of individual solid [particles] cannot."

Amazing Photo

Editor's Note: The photograph below, believe it or not, is authentic and accurately depicts the text that follows; it is an official Navy photograph archived here: http://www.fly.faa.gov/carf/(external link) The text itself is from the THE CGC COMMUNICATOR .

Here is a fabulous photo taken "by a military observer from the deck of an aircraft carrier just as an F/A-18 jet broke the sound barrier." Photo and information courtesy of Oscar Medina, CE of KNSD(TV), San Diego. Oscar assures us that the photo is authentic -- and not an e-artist's creation -- even though the ocean's surface is obscured by haze. The photo was first published about two years ago. About half way down the text on the left side of the page, click on "Amazing Photo!" Oscar adds: "One of my coworkers told me he has actually witnessed the same thing happening when he was in the military. The flares are there for a fraction of a second just as the sound barrier is broken."

An end to telephony, Carl Sagan, and the speed of light

The future might seem unlimited for telephony, with new technologies invented every day. But even telephony has a limit, a barrier it cannot cross: time. For years satellite phones have permitted anyone at any location to call anyone else who has a phone. Going further, a video telephone like the one envisioned by Arthur C. Clarke in 2001: A Space Odyssey, could certainly work in Earth orbit. But such a payphone on Mars would be impossible. Clarke himself reminded us in 1977 that a call would take three minutes to get to Mars and three more minutes to receive a reply. Telephony requires a communication link providing an almost instanteous response between both parties. Such a delay would eliminate telephony, substituting for it a message service.

Although unlimited information could be sent between both parties, the feedback and instant response provided by telephony would be lost. Anyone repairing a Mars orbiting space station will have no quick help from Houston. Delays and confusion will result, especially with problems needing immediate attention. While telephony can overcome distance for us on earth, it itself cannot overcome the distances it must travel; although radio waves race at the speed of light in space, they cannot go any faster.

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