Patent Application
20100221692
Not Applicable
Not Applicable
Exhibiting, exemplifying, and personifying science and technology, the present invention generally relates to the fields of physics, education and demonstration, and measuring and testing. More specifically, it relates to a simple, hand-held, adjustable, educational pendulum instrumented with a visual inertial motion sensor that, like a person, ordinarily flexes to sense changes in motion, but not that of a simple coasting swing. Two disks, bob and sensor, slide on a composite plastic line to configure the educational pendulum for conducting various classical and new experiments.
Ancient wisdom encourages us to test and model all things, especially pendulums, and retain what is good. Galileo, Newton, Foucault and other famous scientists employed pendulums to explore reality. They discovered how interacting objects transferring energy push and pull on one another to move and flex per laws of nature, such as Hooke's Law of Elasticity and Newton's Laws of Motion and Gravitation. And how properties of materials, such as inertia, elasticity, friction, and gravity, which store energy in different ways, oppose moving and flexing.
The instrumented educational pendulum physically models and extends the above energy concepts. It dramatically shows that without a transfer of energy nothing happens, motion does not change, structures do not flex, and sensors do not sense.
Extending this thinking, forces involved in transfers of energy occurring in other energy realms, such as electrical, fluidic, and magnetic, also move and flex things in an analogous way.
The simple, unique, educational pendulum reflects decades of effort developing desktop educational models and pendulous, impulse-hammer calibrators. It combines classical pendulum science with modern sensing and structural dynamics technology. A simple spring-mass structure resembling a lollipop, or the pendulum equivalent, simulates both a person riding the swing and a visual inertial motion sensor, often called an accelerometer Like a person, the sensor structure ordinarily flexes to sense changes in motion, but not that of a simple coasting swing or pendulum, creating a mystery. Solving this mystery develops insight into how forces associated with transfers of energy animate and power things. Perhaps a billion or more sensors with similar structures help trigger air bags, stabilize camera images, test behavior of structures, and monitor the health of machines, among many other applications. The Internet lists over a million references to both pendulums and accelerometers.
Evidently, a pendulum naturally oscillates because the pull of gravity acting along the arcing path of the bob automatically reverses direction as the pendulum passes through vertical, creating a restoring force similar to a spring restraint. Similar resonances in structures, such as sound, noise, vibrations, and waves, often please, annoy, or destroy. Testing, modeling, and modifying the resonant behavior of structures and monitoring structural health are multi-billion dollar industries today.
Through the ages, simple man-made and nature-made objects that swing freely from a pivot have entertained, fascinated, and benefited people in many ways. Serving as a key to nature, pendulums have been used to clock time, time music, measure gravity, detect earth's rotation, sense motion, study orbiting, entertain children, and help educate future scientists and engineers. The educational pendulum exemplifies hands-on, minds-on, inquiry based learning promoted by modern teaching standards. It helps integrate the rather fragmented knowledge taught and memorized in school back into a unified whole.
Blending classical pendulum science with modern sensing and structural technology, the present invention is a hand-held, adjustable, educational pendulum instrumented with a visual inertial motion sensor resembling a lollipop, and an elastic-band force sensor resembling a fish scale. It simply consists of two, movable, hard rubber disks threaded onto a special compressible, flexible line suspended from a metal ring or an elastic band held in a person's hand. Sliding the moveable disks on the composite plastic line configures the structure as a simple, double, conical, or torsional pendulum. It also changes the mass of the bob and length of the suspension arm for science experiments. Plus it collapses the assembly into a compact cylinder for storage as a keychain or paperweight. Variations of the educational pendulum connect the bob and sensor disks with a separate, flexible, elastic rod, tie, or line.
The lower disk and line segment together simulate a rider and a visual inertial, motion sensor. Both ordinarily flex to sense changes in motion, but, not that of a simple coasting swing, creating a puzzling mystery to be solved.
Operating the educational pendulum involves exercising it by manually moving a pivot back and forth at a natural rate, and allowing it to coast. The natural oscillatory behavior of the educational pendulum entertains, puzzles, and enlightens people, as the energy imparted transfers back and forth from being momentarily stored as height in the earth's gravity field (potential) to motion of the bob (kinetic). Shortening the length of the suspension line increases the natural oscillating rate, but changing the mass of the bob does not affect the rate if the length of the pendulum arm is the same. Through gravity, the earth invisibly pulls on the pendulum parts as they pull on the earth, transferring energy when the pull, called weight, moves or flexes them.
Evidently during the above exercises, interacting objects, including the pendulum, earth, sensor, and operator, transferring energy push and pull on one another to move and flex per laws of nature. For example, the operator pushes on the disk or pivot; it pushes back as both move and flex, transferring energy. A bigger push or longer move transfers more energy.
Now, as always, a want and need exists for an entertaining new technical puzzle that introduces science and technology.
Therefore, the primary object of this invention is a fun, novelty item exhibiting relaxing, rhythmic motions and a motion mystery.
Another important object is a fun, physical model to help teach or learn basic force-and-motion science and technology.
Still another object is an educational model that dramatically shows how forces involved in transfers of energy flex sensor structures to sense and communicate information.
Two embodiments of the educational pendulum are illustrated in the following drawings, in which:
FIG, 1 is a sectioned, side view of the invention showing two cylindrical, movable, hard rubber disks threaded onto a composite, flexible, plastic line suspended from a person's hand by a key ring or elastic band.
Sliding moveable disks 12 & 22 on line 32 configures the structure as a simple, double, conical, or torsional pendulum. It also positions disks 12 & 22 on line 32 for various new and classical experiments.
With disks 12 & 22 positioned near each other, but some distance apart, at the lower end of line 32 as shown in
Viewed in the direction of arrow 20, the sensor structure, like a person, ordinarily flexes to sense changes in motion, but not that of a simple coasting swing, creating a mystery. The sensor tilts instead of flexes when the pendulum coasts. Evidently, weight due to gravity of each of the pendulum parts moves them all together as a unit, as they freely fall along the arcing path in a relaxed state tangentially. The moving pendulum and sensor parts interact with the earth, not with each other, as they move freely under the influence og gravity Without a transfer of energy from bob disk 12, the sensor does not flex to sense changes in motion.
Gravity manifested as weight powers the coasting pendulum. Through gravity, the earth pulls on the pendulum parts as they pull on the earth, transferring energy when the pull moves or flexes them. Gravity pulling on the bob and the bob pulling on line 32 stretches or contracts the visual, elastic-band 43 force sensor as the pull changes during an excursion.
Operating the educational pendulum involves configuring it, suspending the bob assembly, manually moving a pivot at ring 42 or band 43 back and forth at a natural rate, and sensing or observing the resultant motion.
Evidently, a varying centripetal pull of line 32 on disk 12 guides the bob in an arc. Weight due to gravity acts to move the bob along the arcing path, and to further tension line 32. Pull on line 32 is greatest as it passes through vertical. Pull of gravity propelling the bob along its arcing path and the resulting change in motion is greatest at the ends of the excursion, as indicated by tilt of the sensor when the pendulum is being manually powered.
Testing behavior of the instrumented pendulum involves moving the pivot back and forth at slow, medium, and fast rates. At slow rates the bob assembly is pulled along to follow the pivot. At a medium rate the pendulum naturally oscillates, slowly building up big excursions. At a fast rate bob disk 12 remains almost still because of its inertia, while the pivot moves and the sensor wobbles to sense changes in motion.
Placing disks 12 & 22 together on line 32 forms a simple pendulum that behaves in a classical way. It swings at a preferred natural rate when coasting. Placing bob disk 12 at knot 33 and swinging from either disk 12 or 22, changes the swinging rate very little. Evidently, changing the mass of the bob does not change the natural swinging rate when the length of the pendulum arm is the same. As Newton profoundly observed, this can happen only if a change in motion (acceleration) is caused by force and opposed by mass, because adding or removing material to the bob does change both the mass (inertia) and force (weight).
Shortening the length of the pendulum arm by positioning disk 12 & 22 assembly at the mid-point of line 32 greatly increases the natural swinging rate because the restoring force on the bob due to gravity is greater for a given distance from vertical.
Conducting the above experiments, solving the motion mystery, and explaining observed pendulum behavior develops insight into how forces involved in transfers of energy animate and power the world.
Evidently, interacting educational pendulum parts transferring energy push and pull on one another and on the earth to move and flex per laws of nature. But, without an energy transfer from the swinging object, the sensor does not flex or sense. Thus, the instrumented pendulum serves as an ideal model for exhibiting energy transferring, storing, and animating things.
Such interactive transfers of energy, which are involved in all that happens, could be called eneracting, a new word. Toying with the instrumented educational pendulum encourages people to have fun naturally eneracting, and to enjoy seeing other people and things eneract.
Naturally oscillating pendulum behavior has been thoroughly tested, analyzed, and modeled by a host of dedicated scientists and technologists, including Galileo, Newton, and Foucault. Mathematical analyses referenced in Wikipedia, the open encyclopedia, show the behavior herein attributed to the instrumented educational pendulum is only approximate, and good only for small excursions, but the small deviations are not visually discernable. A tiny, pendulous, inertial motion sensor placed at the center of the educational pendulum bob would eliminate most of the secondary effects causing discrepancies.
