On Sat, 4 Aug 2007, Hans von Lieven wrote: > http://www.keelytech.com/forum.html > > Just came across an old article of yours where it says: > "IDEA: Try building a sort of rotating "Radiometer" with several > "paddles",with one surface of each paddle covered with a drinking-straw > array. One side of each paddle will act as a reflector, while the other > behaves as a good absorber at resonance. Place a needle-bearing in the > center of the assembly so the paddles can rotate horizontally. Now play > a very loud sound in the room, with the frequency at the resonant > absorption band of the drinking straws, and perhaps the "pinwheel" will > begin to turn because of radiation pressure differences." > > Your speculation is right of course, have a look at the above URL that > shows an acoustic turbine that has been around since Keely's time and > works.
Cool! I'll add the Keelytec URL to my links at NOT YOUR AVERAGE CONSTRUCTION PROBJECT, so other hobbyists can have a go. It's at http://amasci.com/weird/const.html I did hear a Keely story from Jerry Decker, where as a child Keely built a pinwheel device with conch shells at the ends of the crossbars. It supposedly rotated when loud sounds were made. I don't know whether the device should rotate backwards or forwards. Have you built one? For example, the ultrasound beam in an "ultrasonic humidifier" and in mist-makers is creating a unidirectional water jet which spurts upwards from the transducer. As the piezo-piston moves forward, it "blows" water in a single direction, but as it moves backwards, it "sucks" water from all directions. (This is apparently due to water having high inertia and low viscosity, i.e. low Reynolds number effects.) If suspended in an aquarium, the water jet should drive the transducer backwards via reaction. There's another phenomenon: if a "smoke ring launcher" is fired repeatedly, the stream of smoke rings behaves like a fluid jet which carries mass. Again, the jet should drive the launcher backwards by reaction. On the other hand, a Helmholtz resonator is a sharply tuned absorber, and such an absorber will suck in sound and turn it into heat. The radiation pressure on the remainder of the resonator's outer surface will be unbalanced, and the resonator will move along, as if it's outside was radiating sound and its hole was absorbing it. It moves opposite to a jet-launching device, moving TOWARDS its opening. (This effect might be stronger if the inside of the resonator contained some glass wool or thin soda straws, enough to increase the absorption but without reducing the Q-factor and broadening the absorption band too much.) Mist-maker underwater ultrasonic beam http://www.artisticdelights.com/ulfog.html http://www.mainlandmart.com/fogger1.html > Funny the physics books no longer mention this device, they once did. That's pretty normal. No conspiracy needed. All the easily-explained physics devices become very popular in classrooms, while mysterious ones are a slight embarrassment which makes the teacher look bad, and gives a bit of power to the students. I'd predict that such demos would be first unpopular, then eventually deleted from sales catalogs (since unpopular means unimportant, RIGHT?) In my explorations I've begun to suspect that conventional scientists have highly tuned psychic intuition, and they listen to a subconscious voice which steers them away from any revolutionary discoveries. Revolutions can cause you to lose your job, or destroy your scientific career and have all your colleagues turn against you. A sensitive human would learn to listen to such a "voice" in order to survive in the world of science research. In fact, I've found that if I start talking about niche subjects which may lead to major revolutions, some researchers get mad and attack with visciousness all out of proportion. The rank-and-file scientists are more prone. Wanna-be scientists do this (such as non-PhD research staff.) But there still are many odd ducks who are attracted to such things. Many scientists ENJOY crackpotism and blasphemous thinking. J. Wheeler said "In any field, find the strangest thing and then explore it." Too bad that so many researchers vigorously do the exact opposite. They know deep down that the herd-followers get the grants. Unless their fame prevents it, a stray sheep gets eaten. (But they're eaten not by wolves but by the other sheep!) Jonathan Swift said "When a true genius appears in this world, you may know him by this sign, that the dunces are all in confederacy against him." But swift got it wrong. He should have said that all the contemporary thinkers are in confederacy against him. (But then Swift probably considered scientists to be dunces.) Also, his term "true genius" needs explanation. A good definition comes from William James: "Genius in truth means little more than the faculty of perceiving in an unhabitual way." So "unhabitual" includes altered mental states as well as crackpot ideas. Little known story: Einstein stumbled into his world-changing theories after a week of being sick in bed, and seeing things during fever-dreams which no habitual-thinking physicist had ever seen. PS Have you seen my idea for explaining the Keely water cannon? It involves acoustics and the laminar nonturbulent boiling-explosion of extreme-superheated water. (If the cannon used cold water, then my explanation is wrong.) http://amasci.com/news.html#keelycannon (((((((((((((((((( ( ( ( ( (O) ) ) ) ) ))))))))))))))))))) William J. Beaty SCIENCE HOBBYIST website billb at amasci com http://amasci.com EE/programmer/sci-exhibits amateur science, hobby projects, sci fair Seattle, WA 425-222-5066 unusual phenomena, tesla coils, weird sci
