How Airplanes Fly. Please let me remind all of you--this material is copyrighted. Though partially funded by NASA, it is still a private site. Therefore, before using our materials in any form, electronic or otherwise, you need to ask permission. There are two ways to browse the site: (1) use the search button above to find specific materials using keywords; or, (2) go to specific headings like history, principles or careers at specific levels above and click on the button. Teachers may go directly to the Teachers' Guide from the For Teachers button above or site browse as in (1) and (2). Almost everyone today has flown in an airplane. Many ask the simple question "what makes an airplane fly"?
The answer one frequently gets is misleading and often just plain wrong. Let us start by defining three descriptions of lift commonly used in textbooks and training manuals. The second description we will call the Popular Explanation which is based on the Bernoulli principle. The popular explanation of lift. Principles of physics: a calculus ... Physics - Content by Unit. A particle is an object so small that its size is negligible; a wave is a periodic disturbance in a medium. These two concepts are so different that one can scarcely believe that they could be confused. In quantum physics, however, they turn out to be deeply intertwined and fundamentally inseparable. Figure 7: A circular wave created by tossing a pebble in a pond. Source: © Adam Kleppner. More info The electron provides an ideal example of a particle because no attempt to measure its size has yielded a value different from zero.
The essential properties of a particle are its mass, m; and, if it is moving with velocity v, its momentum, mv; and its kinetic energy, 1/2mv 2. Figure 8: Two waves interfere as they cross paths. Source: © Eli Sidman, Technical Services Group, MIT. A wave is a periodic disturbance in a medium. (the Greek letter "lambda"), the distance from one crest to the next; its frequency Figure 9: Standing waves on a string between two fixed endpoints.
Mathematics Illuminated | Unit 10| 10.3 Sound and Waves. Sound is caused by compression and rarefaction of air molecules. We perceive the amplitude of a sound wave as its loudness, or volume. We perceive the frequency of a sound wave as its pitch. As we have seen, the Greeks recognized connections between harmonic intervals and rational numbers. As it turns out, they also had a rudimentary understanding of the most basic musical concept of all…sound. We are all familiar with waves of one sort or another. Imagine the smooth surface of a pond on a still day. Notice that both the crests and the troughs reach equally above and below, respectively, the still surface line. To be precise, a rock hitting a pond creates an impulse, a temporary disturbance. If the child's mother is fishing in the same pond, her bob will move up and down with the crests and troughs of the ripples.
As these groups of molecules alternately experience compressions and rarefactions, a pulse is created, and this is what "reaches" our ears. Back to top. Acoustic Interferometry. Finding out what is in a closed container can be a daunting task when you can't open it—either because its contents may be toxic or because it is someone else's property. "Why not just tap and listen? " Dipen Sinha once suggested to a group of government officials gathered to assess ways to verify compliance with the 1990 U.S. /Soviet Union Chemical Weapons Treaty. Requiring only a metal key, his simple strategy was nonetheless effective. Since formalizing that idea by developing a sound-based tool for noninvasive fluid identification, Sinha has assembled a team of talented scientists and technicians, inventors who seem capable of devising endless uses for sound.
With backgrounds in theoretical physics, chemistry, engineering, and hardware and software design, this versatile team has tackled such questions as "is this food fit to eat" and "where are the best oil deposits? " The team's contribution to safety, health, and security is evident in each of these envisioned sound solutions. Resonant Interactions Among Surface Water Waves - Annual Review of Fluid Mechanics, 25(1):55. BAE joins wave energy project - Business News, Business. Ocean Wave Energy. From PESWiki See also PowerPedia:Ocean Wave Energy Methods for harnessing the undulating action of waves to generate usable energy. From research and development to presently implemented solutions that harness the power of waves for energy production.
Overview Ocean Energy Potential - Ocean energy is mostly in an experimental stage but some of its component technologies have the potential to become mainstream energy sources and are now being trialed. Elementary primer on three basic ways to tap the ocean for its energy. We can use the ocean's waves, we can use the ocean's high and low tides, or we can use temperature differences in the water. Electricity from the sea - In a world addicted to fossil fuel, turning waves into watts might seem far-fetched, but ocean power is gradually joining the ranks of wind and solar as a source of renewable energy.
Putting It All In Perspective - Renewable energy may hold the key to both national security and economic stability. Events Wave Buoys Companies. EMEC: European Marine Energy Centre - Services. EMEC: European Marine Energy Centre - Wave Energy Devices. Wave Power - Energy from ocean surface waves. Ocean Wave Electric Power Generation - Thermal Systems. Introduction: The Need for Alternate Energy Sources In today’s world, the development of sustainable energy sources is coming to the forefront of issues to stop the damage to our planet. Wind farms and solar panels tend to dominate thought when thinking of sustainable energy sources, but one of the most underutilized and prevalent sources of sustainable energy is the world’s oceans. As most of the world is covered by the seven oceans, and also large gulfs and inland seas, it seems like a logical choice to powering our world renewably.
The Potential of the Wave Powered Suction Turbine One technology that has been getting a lot of attention from sustainable energy initiatives is that of the wave powered suction turbine. This technology is one of the first viable power sources that taps into the boundless resource of dynamic bodies of water. How It Works The steadiness of the electrical power output can be unpredictable, and has been part of the systems commercial drawbacks. Resources: D. Giant sea Anaconder promises green power. Anyone scuba diving off the coast of the UK in three years time could be in for a shock. A new device that creates electricity from wave power has been unveiled by Checkmate Sea Energy – and it looks like a giant sea snake. The Anaconda Wave Energy Converter is a long rubber tube filled with water. When it's placed in the sea and anchored to a generator, the movement of water pushes the tube back and forth, creating "bulge waves" inside it.
That builds up pressure that drives a turbine and generates electricity. It is estimated that a 200-metre Anaconda could provide enough energy to power 2,000 homes. One advantage of the new system is that it sits below the water level, so it does not spoil coastal views. The UK has excellent conditions for generating marine energy and the industry has been steadily growing over the past 25 years. Nick Cooper, a freelance writer, can be contacted at nickcooper.freelance@googlemail.com. Next-gen wave-power generator is just swell. An Australia-based company has engineered an innovative wave-power technology which overcomes the most significant challenges hampering development in the field: the unpredictability of waves as an energy source and technical problems caused by corrosion and devastating storms.
Instead of dealing with the unreliable energy-generating properties of ocean waves, Oceanlinx's technology goes a little deeper: their technology harnesses the power of swells, which are far easier to predict than surface waves due to their long-wavelength oscillation. The plant is based in part on the design of offshore oil rigs, which float above the surface and are stabilised by massive heave plates (which look like ducks' feet) that are tethered to the ocean floor. As the ocean swell passes, the heave plates move up and down to keep the oil rig level. Instead of using the heave plate design for stabilisation, Oceanlinx's harnesses the vertical movement caused by the swell for energy generation. Orkney Islands try new wave power system. A new type of wave power harnessing machine called the Oyster will be installed off the Orkney Islands for trials beginning this Autumn.
The device is different from other wave power devices because it uses hydraulic technology to transfer the power it harvests to the shore. Dr Ronan Doherty, chief technical officer of Aquamarine Power, the Edinburgh-based company that has designed the Oyster, told Science Daily: "A key design feature is a 18-metre wide oscillator. " The oscillator, a large paddle that moves to and fro with the waves, is attached to a piston which pumps water to the shore. There, the water is converted into power by conventional hydroelectic generators. The Oyster, which is at the concept stage at the moment, is designed to be deployed in water depths of 12 to 16 metres. However, it is also a simple design, which means that there are fewer submerged moving parts that could be damaged in bad weather. Equation: Gauging the Awesome Power of Waves | Magazine.
Giant Waves Solve Saturn Ring Mystery | Wired Science. Saturn’s largest ring appears to behave like a mini spiral galaxy. NASA’s Cassini spacecraft caught enormous waves sloshing back and forth across Saturn’s B ring, similar to waves believed to give galaxies their spiral shapes. “This is a major result,” said Cassini imaging team leader Carolyn Porco of the Space Science Institute. “Saturn’s rings are tiny tiny tiny compared to a galaxy, but we see the same physics.” The new observations also show two warped regions, including a tall arc of spiky peaks that rise almost two miles above the ring plane. These perturbations may have been sculpted by small moons that migrated across the ring disk, a process believed to be important in shaping planetary systems.
Saturn’s most massive ring, the B ring, has baffled astronomers since the Voyager spacecraft flew by in 1980 and 1981. “Think of it like waves in a pool,” Porco said. In Saturn’s rings, the waves are more like compressions in a Slinky than water waves, but the physics is similar.