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| A The Acceleration Vector Barrier Penetration by Waves The Center Of Mass Diffraction and Scattering Around Obstacles Effect of Phase Differences Between Sources Ferromagnetic Domain Wall Motion Galilean Relativity: Ball Dropped From Mast Of Ship Human Momenta Inertial Forces - Centripetal Acceleration J Kepler’s Laws Liquid Drops A Matter of Relative Motion | N Newton’s First and Second Laws One Dimensional Motion Packets In Crystal Q Random Walk and Brownian Motion Sand Pendulum #3 Tacoma Narrows Bridge Collapse (Missing) Unusual orbits Velocity and Acceleration in Circular Motion Wave Packets In Periodic Potentials Packet Incident On A Crystal X Y Z |
| THE ACCELERATION VECTOR |  |
Educational Services Incorporated (E.S.I)
The velocity vector for a spot moving in an irregular but repeated path is displayed on an oscilloscope screen. Acceleration is introduced by showing that the head of the velocity vector moves in a comparable but different path. A computer then determines the speed and directions of the head of the velocity vector and displays this also as an arrow, indicating the acceleration of the original spot. B & W, 3 min. 15 sec.
| ACROBATIC ASTRONAUTS | |
No description available.
| BARRIER PENETRATION BY WAVES | |
Educational Services Incorporated (E.S.I)
A wide channel of deep water between two shallow regions in a ripple tank acts as a finite barrier to a wave incident from one of the shallow regions. The incident wave is totally reflected. The loop demonstrates that as the channel is narrowed, the reflection diminishes and the transmission across the channel increases B & W, 2 min. 5 sec.
| BRAGG REFLECTION OF WAVES | |
Educational Services Incorporated (E.S.I)
Bursts of a straight wave are incident on a two-dimensional array of pegs. Waves move through this lattice, but part are scattered from each peg. Interference of the scattered components produces a strong reflection at the Bragg angle. Wavelength, λ, is decreased until strong reflection is destroyed, then further decreased to half its original value, whereupon strong reflection is restored. Finally, without changing λ, the effect is shown of shifting lattice position, i.e. changing the angle of incidence. B & W, 3 min. 40 sec.
| THE CENTER OF MASS | |
Introduces the concept of Center of Mass, and shows its properties when systems of masses are set in motion.
| CENTRAL FORCES: Iterated Blows | |
A dot on a cathode-ray tube controlled by a computer moves under the influence of random blows of a central force. The student can determine that Kepler's law of equal areas holds by projecting the Film-Loop on paper. These random blows are replaced by blows toward the center and proportional to the distance from the center. The frequency of the blows is increased to produce a smoother, elliptical orbit. In a final sequence the computer generates a display simulating two planets acting under an inverse square force. Color, 3 min. 45 sec.
| CHARGES THAT STOP | |
Education Development Center (E.D.C.)
Depicts what happens to the electric-field distribution of a charge when the moving charge is brought to a stop.
| CHARGES THAT START AND STOP | |
Education Development Center (E.D.C.)
Illustrates what happens to the electric-field distribution of a charge moving with a velocity close to that of the speed of light in free space as the charge is stopped and started.
| CIRCULAR WAVE REFLECTION FROM VARIOUS BARRIERS | |
Educational Services Incorporated (E.S.I)
Circular pulses are reflected by a straight barrier. An animated source behind the barrier generates an image pulse simultaneously with the real pulse. The expanding image pulse coincides with the real reflected pulse. The circular pulses generated in the center of the circular barrier are reflected and converge to the point of origin. Pulses are then generated at several positions along the major axis of an elliptical barrier. When the source is at one focus, all parts of the reflected pulse arrive simultaneously at the other focus. B & W, 3 min. 25 sec.
| THE CONCEPT OF CHANGING FLUX | |
Dr. Richard B. Adler: Massachusetts Institute of Technology
The various ways in which the magnetic flux through a coil may be made to change are illustrated, with the resulting induced voltages observed qualitatively: a loop normal to a magnetic field is suddenly contracted; a loop is rotated in 90o steps through a full 360o, so that the intercepted flux varies from positive through zero to negative, and return: this rotation is repeated after the loop is twisted into a figure 8, to observe no voltages, and again with the figure 8 folded over on itself to make a two-turn coil: the magnetic field is switched on and off with the coil fixed in orientation; and the coil is passed down through the magnetic field, from well outside it above to well outside it below. This last sequence is related to the action of a magnetic tape player by passing a bar magnet fixed to a paper tape over the pole gap of an unenergized electromagnet whose winding is used as a pick-up coil to generate the induced voltage instead. Color, 3 min. 40 sec.
| CONCEPTS OF MOTION: Projectile Fired Vertically | |
No description available.
| CONSERVATION OF ENERGY: Potential to Kinetic | |
Dr. J.L. Stull: Alfred University
Three examples of the principle of conservation of energy are demonstrated. Work is transformed into kinetic energy by accelerating a glider with the constant force device used in "Newton's First and Second Laws". Gravitational potential energy is converted to kinetic energy by accelerating a glider down an inclined track. Elastic potential energy is converted by projecting a glider with a compressed spring. In each case, the expression is quantitative; the glider's velocity at a known distance is derived from a recorder-trace. Color, 2 min. 50 sec.
| CONSERVATION OF LINEAR AND ANGULAR MOMENTUM | |
H.F. Meiners: Rensselaer Polytechnic Institute
Two frictionless dry-ice packs are connected by a light rod. When struck at the center of mass, the system translates without rotating. When struck off center, the system rotates and translates. After two qualitative demonstrations of these effects, quantitative experiments are conducted from which the student can calculate predicted and observed linear and angular velocities for the system. The momentum imparted to the system by a small ball propelled by a spring launcher is determined by means of a ballistic pendulum. Spark paper records the motion of the center of mass of the system and the path of one of the pucks. These data enable the student to check the observed velocities against his predictions. Color, 3 min. 40 sec.
| CONSERVATION OF MOMENTUM: Elastic Collisions | |
Dr. J.L. Stull: Alfred University
Gliders on an air track are used to demonstrate the conservation of momentum in elastic collisions. Elastic and inelastic collisions are first contrasted using sequences photographed in real and reversed time. Several examples of elastic collisions are then introduced as problems. Finally, a "projectile" glider is projected at a stationary "target" glider. Their motions are subsequently "frozen" and their respective distances from the impact point are measured. Color, 4 min. 15 sec.
| CONSERVATION OF MOMENTUM: Inelastic Collisions | |
Dr. J.L. Stull: Alfred University
By means of gliders on an air track, inelastic collisions are contrasted with elastic collisions. Then, in a series of quantitative demonstrations, a "projectile" glider is projected at a stationary "target" glider. Two clocks are shown. One clock records the time the projected glider takes to travel a given distance, while the second records the time both gliders take to travel an equal distance after impact. Readings are taken for various mass ratios. Color, 3 min. 55 sec.
| CONSTANT VELOCITY AND UNIFORM ACCELERATION | |
Dr. J.L. Stull: Alfred University
A glider's passage along a track is detected by photocells and recorded on a time-trace (viewed simultaneously in the lower half of the frame). Peak separations measure the time taken to pass between adjacent photocells. Peak widths yield approximate values for the glider's "instantaneous velocity." The loop then shows constant velocity along a level track and uniform acceleration down a track at three different inclinations. The traces are reproduced in the film notes to provide a basis for calculating the acceleration of gravity. Color, 4 min. 25 sec.
| COUPLED OSCILLATORS: Energy Transfer | |
Educational Services Incorporated (E.S.I)
Two long, coupled pendulums are started in synchronization and oscillate at uniform amplitude. Then, one pendulum is started while the other remains at rest; energy is transferred from one to the other and back again. The effect of altering the coupling is shown. Finally, in an extremely elegant demonstration, coupled sand-pendulums leave traces on a black moving table and provide a plot of amplitude variation with time. Color, 3 min. 35 sec.
| COUPLED OSCILLATORS: Normal Modes | |
Educational Services Incorporated (E.S.I)
Symmetric and anti-symmetric normal modes are shown for coupled pendulums. These oscillations are compared with single pendulums, each having an effective length equal to each normal mode. The frequencies of the single pendulums equal those of the two normal modes of the coupled pendulums. The single pendulums of different lengths show beats; the coupled pendulums exchange energy at this beat frequency. Color, 3 min. 40 sec.
| COUPLED OSCILLATORS: Other Oscillators | |
Educational Services Incorporated (E.S.I)
This Film-Loop demonstrates the exchange of energy between coupled mechanical oscillators made from a variety of very simple materials. The frequency of the energy exchange is shown to depend on the coupling between a set of spring oscillators. The demonstrations in this Film-Loop were designed and performed by Alan Holden of Bell Telephone Laboratories, Inc. Color, 3 min.
| CRITICAL TEMPERATURE | |
Franklin Miller, Ohio State University
The critical temperature of a substance is the temperature above which it cannot exist as a liquid and above which pressure alone cannot liquefy it.
| DIFFRACTION AND SCATTERING AROUND OBSTACLES | |
Educational Services Incorporated (E.S.I)
A wave defracts around the edge of a barrier. As the wavelength decreases, the disturbance behind the barrier is confined to a region closer to the edge of the barrier. Diffraction of waves by obstacles is shown. Wavelength is increased until it approximately equals the obstacle's size and there is no apparent disturbance of the wave front. Finally, scattering from very small objects is shown. B & W, 2 min. 50 sec.
| DOPPLER EFFECT | |
Educational Services Incorporated (E.S.I)
A pulsed air jet, producing a circular wave, moves over water at 1/3 and 2/3 of wave velocity. The doppler effect is clearly visible. At one point, motion is "frozen" to permit close examination of the wavelength differences. B & W, 3 min. 15 sec.
| THE DOPPLER EFFECT AND THE TWIN PARADOX | |
Robert Ehrlich, S.U.N.Y. at New Paltz
The first part of this film deals the relativistic Doppler effect; the change in the frequency of waves reaching a detector that occurs when the source and the detector are in relative motion. The second part of the film deals with the twin paradox; an unequal passage of time for a pair of twins, one of whom goes on a round-trip rocket flight while the other stays home.
| DROPS AND SPLASHES | |
G. Gray: Newton Schools
With the aid of a high-speed camera, surface tension effects which occur too fast for the eye to see are demonstrated. In real time and then in slow-motion this loop shows (1) the "beading effects" of drops in a falling stream of water; (2) the splash of a drop of milk in a cup of coffee and in a glass of milk; and (3) the "crown effect" produced by a drop of milk splashing on a flat surface. These remarkable slow-motion color sequences were photographed by Dr. Harold Edgerton and Dr. Tsuneyoshi Uyemura of M.I.T. The special camera they used takes approximately 4,000 pictures a second. The projector shows about 20 pictures a second so an event taking one second lasts for 200 seconds (over three minutes) on the screen. Color, 3 min. 30 sec.
| EFFECT OF PHASE DIFFERENCES BETWEEN SOURCES | |
Educational Services Incorporated (E.S.I)
At a given wavelength and source separation, the phase difference between two sources is altered so that the positions of interference maxima and minima are exchanged. Then, the one source is continuously retarded, and the interference pattern sweeps continuously about the origin. A superimposed reference mark identifies the effect of the beats. B & W, 2 min. 5 sec.
| ELECTROSTATIC INDUCTION | |
Dr. A.E. Walters: Rutgers - The State University
Objects charged by contact have the same type of charge as the objects with which they were contacted, but objects charged by electrostatic induction have the opposite charge. Two metal spheres mounted on insulating stands, are brought into contact with each other and a charged rod brought near one of them. With the rod still close by, the two spheres are separated. When each in turn is brought near a charged ball, the sphere which was originally further away from the charged rod repels the ball; the sphere close to the charged rod attracts the ball. When the spheres are brought in contact, neither sphere exhibits any attraction for the ball. Color, 4 min. 5 sec.
| EQUIPARTITION OF ENERGY | |
Dr. H.A. Daw: New Mexico State University
A mixed population of pucks with masses of M and 2M is studied. By means of superimposed animation, each puck trails a line showing its path. From these data, histograms are developed for the two types of pucks. Maxwell's distribution and the root-mean-square speeds are superimposed on the histogram and compared for the two puck types. The film notes ask the student to compare the mean kinetic energies. In the last part of the loop, the 2M pucks are replaced by 4M pucks and the student is asked to predict the rms speed of these larger pucks. Color, 2 min. 55 sec.
| FERROMAGNETIC DOMAIN WALL MOTION | |
Franklin Miller, Ohio State University
In a ferromagnetic substance, the atoms are grouped into domains which are of the order of 0.01 to 0.1 mm in size containing some 1011 to 1020 atoms with their electron spins all aligned parallel to each other. The electrons of adjacent domains are initially aligned in different directions. The process of magnetization involves growth of those domains which are already aligned parallel to the external magnetizing field.
| FIELD VS. DISTANCE | |
Dr. Richard B. Adler: M.I.T.
The magnetic field produced by the current in a straight vertical wire is measured at various distances from the wire. The measurement is made in terms of the earth's horizontal field, by adding the two fields at right angles and noting the resulting heading of a compass needle. An animated sequence relates these results to those expected in the relationship of the field at the center of a current-carrying coil to the coil radius. This experiment is then performed by the same technique, employing three different size coils and the earth's field. Color, 3 min. 40 sec.
| FIXED SYSTEMS OF ORBITING BODIES | |
Education Development Center
Using computer generated animation this demonstration shows the behavior of two bodies attracted to each other by a force varying inversely as the square of the separation of the bodies. The initial velocities in each case are chosen so that the center of mass of the system remains at rest. 3 min, 40 sec
| FORMATION OF SHOCK WAVES | |
Educational Services Incorporated (E.S.I)
A pulsed air jet, producing a periodic circular wave, moves over water at 1/3 and 2/3 of wave velocity. When source velocity exceeds wave velocity (by about five percent) a shock wave builds up and moves along with the source. When the ratio of source velocity to wave velocity is 1.6, the cone of the shock wave is quite sharp. At one point, motion is "frozen" to show the relationship between the angle of the shock wave and the wave and source velocities. B & W, 3 min. 25 sec.
| GALILEAN RELATIVITY: Ball Dropped from Mast of Ship | |
No description available
| HUMAN MOMENTA | |
No description available
| INERTIAL FORCES: Centripetal Acceleration | |
The concept of centripetal force is illustrated in a clear and dramatic way using a "Rotor Ride" in an amusement park. Passengers stand against the inside wall of a large, rotating cylinder which reaches a maximum angular speed of 27 revolutions/minute. At this speed, the floor is dropped, leaving the passengers held firmly to the wall. The action is filmed both from a stationary frame of reference and from within the rotor. Color, 2 min. 50 sec.
| INERTIAL FORCES: Translational Acceleration | |
The concepts of force, acceleration and constant velocity are illustrated by a 156-pound student riding in an elevator. He experiences a measurable increase in weight when the elevator starts up, and a decrease when it accelerates downward. When moving at a constant speed between floors, his weight is normal. The camera displays the dial of a sensitive balance on which the student stands during the experiment. Color, 1 min. 50 sec.
| INTERFERENCE OF WAVES | |
Educational Services Incorporated (E.S.I)
An interference pattern is produced by two sources vibrating in phase. Motion is "frozen" while the source separation (d) and wavelength (λ) of the periodic waves are defined. A superimposed reference mark identifies a first-order maximum. Then d is doubled without changing λ. In the new interference pattern, the reference mark lies on the second-order maximum. Keeping d constant, λ is doubled, and the reference mark returns to first-order maximum. Finally, the interference pattern is slowly changed by decreasing λ. B & W, 3 min. 40 sec.
| KEPLER'S LAWS | |
A computer program calculates the changing positions of two planets moving under an inverse square force law around a sun, and displays their positions on a cathode-ray tube at regular intervals. By projecting the Film-Loop on paper, the student may check Kepler's laws by marking the successive planetary positions and by calculating areas swept over by the planet-sun line in equal time intervals. Since the computer was not proving a theory it "knew," but merely computing data to fit the force laws and initial conditions, the student can better appreciate the triumph of Newton's laws of mechanics which explained Kepler's laws for planetary orbits. Color, 2 min. 15 sec.
| LIQUID DROPS | |
No description available
| A MATTER OF RELATIVE MOTION | |
The concepts of relative motion and frame of reference are introduced using collisions as examples. The collision of two cars is viewed as filmed in three distinct frames of reference: that of the moving car, of the laboratory, and of the initially stationary cars.
| MAXWELLIAN SPEED DISTRIBUTION | |
Dr. H.A. Daw: New Mexico State University
The distribution of speeds of the atoms and molecules in a gas is studied using an air table and plastic pucks. Vibrating walls maintain the "temperature" of the "puck gas." The technique for measuring and plotting speeds is demonstrated. Through superimposed animation, each puck trails a line showing its path during a brief time interval. The distance moved in puck diameters, the time in number of film frames and the speed of the puck in diameters per frame are displayed beside each path. Using 19 such samples, a histogram is developed for the number of pucks in each speed interval as a function of puck speed. To illustrate the data-smoothing that accompanies increased date points, the histogram area is held constant. Finally, Maxwell's distribution and the root-mean-square speed for a two-dimensional gas are superimposed on the histogram. Color, 4 min.
| MODELS OF THE ATOM: Thompson Model of the Atom | |
No description available.
| MULTIPLE SLIT DIFFRACTION | |
Educational Services Incorporated (E.S.I)
The interference pattern from two narrow slit sources is shown to be similar to that produced by two point sources. In both cases the same wavelength is used and the source separation equals the slit separation. Two, three, four and eight slit interference maxima are shown. Zero and first-order beams are identified by superimposed guides. B & W, 3 min.
| NEWTON'S FIRST AND SECOND LAWS | |
Dr. J.L. Stull: Alfred University
A special three-section, ten-meter track is level in the center and inclined at each end. A glider traversing the level section is subject to practically zero retarding force. The inclined end sections reverse the glider's direction without introducing any additional source of energy loss. A clock records the glider's transit time between two markers on the level section. Another records total elapsed time. Another glider is attached by a string and a long thread to a device which produces a constant force. The extension of the spring measures the tension in the thread. The glider, initially at rest, is accelerated for a known distance, and the time is measured. Readings are taken for various masses and accelerating forces. Color, 4 min. 20 sec.
| NEWTON'S THIRD LAW | |
Dr. J.L. Stull: Alfred University
This Film-Loop demonstrates the famous reaction-car experiment proposed by Ernst Mach. Two gliders which are initially at rest on an air track are forced apart by a compressed spring. Their motions are subsequently "frozen" and the distances they have traveled are measured. The experiment is performed using gliders of various mass ratios. Finally, we observe the oscillation of pairs of gliders (of equal and unequal masses) joined by a spring. Color, 3 min.
| NUCLEAR RADIATION DETECTORS, Part II. | |
No description available
| ONE-DIMENSIONAL MOTION | |
H.F. Meiners: Rensselaer Polytechnic Institute
Real-time plots of displacement, velocity and acceleration versus time are shown for a small cart being pulled back and forth along a track. First, the student sees the cart on a l0-toot track being pulled back and forth by a chain while a small X-Y recorder, mounted on an overhead projector, plots the displacement of the cart as a function of time. Then, in three successive scenes, the cart is seen in the lower half of the picture, traveling the full length of the track and back again. The upper half of the picture is occupied by the X-Y recorder which plots displacement, velocity and acceleration as the cart traverses the track. A potentiometer on the drive motor provides the displacement data, a tachometer the velocity, and a computer differentiation of the tachometer output supplies the acceleration. Color, 3 min. 10 sec.
| ORBITING BODIES IN VARIOUS FORCE FIELDS. Part I: Positive Power Laws | |
Education Development Center
Using computer generated animation these demonstrations show the behaviors of two bodies attracted to each other by a force varying as the positive power of R; the force gets larger as the bodies move farther apart. 2 min, 35 sec
| ORBITING BODIES IN VARIOUS FORCE FIELDS. Part II: Negative Power Laws | |
Education Development Center
Using computer generated animation these demonstrations show the behaviors of two bodies attracted to each other by a force varying as the negative power of R; the force gets smaller as the bodies move farther apart. 3 min, 35 sec.
| PACKETS IN CRYSTAL | |
Part I of a series of computer-animated sequences on wave packets in crystals. This sequence shows the free propagation of a Gaussian wave packet in a one-dimensional periodic potential for three different choices of average crystal momentum of the packet: (a) in the first allowed energy band below the band gap. (b) at the band gap, and (c) in the second allowed energy band, just above the gap.
| PARAMAGNETISM OF LIQUID OXYGEN | |
Franklin Miller, Ohio State University
Liquid oxygen adheres to pole pieces of a magnet. A comparison is made with liquid nitrogen which is not paramagnetic. Liquid oxygen is strongly paramagnetic; only a few iron-containing substances have larger paramagnetic susceptibilities. This magnetic property is related to the electronic shell structure of the oxygen molecule. In the film, oxygen is used in the liquid state to obtain a sufficiently large density of paramagnetic molecules.
| PARTICLE IN A BOX | |
Education Development Center (E.D.C.)
This computer-animated sequence shows the periodic time dependence of a wave packet confined in an infinitely deep square-well potential. B & W, 3 min, 40 sec.
| THE PHOTOELECTRIC EFFECT | |
Dr. A.E. Walters: Rutgers - The State University
A zinc disk, freshly cleaned on one side, is mounted on the top of an electroscope and negatively charged by contact. A mercury vapor light is pointed at the plate discharging the electroscope. When the same rod charges the plate by induction positively, the electroscope is not discharged. An incandescent lamp is substituted for the mercury light with no effect. The active (ultraviolet) component of the light fails to pass through cardboard and ordinary window glass, but passes readily through quartz. The zinc plate when turned so the ultraviolet light falls on the dull oxidized side fails to discharge the electroscope. However, when the oxidized side of the zinc disk is polished with an emery cloth, the photoelectric effect is again observed. Color. 4 min. 5 sec.
| RANDOM WALK AND BROWNIAN MOTION | |
Dr. H.A. Daw: New Mexico State University
Random walk is studied by following a single odd-colored puck moving in a simulated "hot gas" of yellow pucks. The path of the puck is recorded by mounting a light on it and making a time-exposure photograph in the dark. The free-path lengths are measured and plotted as a histogram. The theoretical distribution and mean free path are superimposed on this histogram. The effect of increasing the mass of the odd particle is investigated. When a very large disk is introduced, its response approaches Brownian motion. Color, 3 min. 50 sec.
| REFERENCE FORCES | |
No description available
| REFLECTION OF WAVES FROM CONCAVE BARRIERS | |
Educational Services Incorporated (E.S.I)
Circular pulses are generated at several points along the axis of a parabolic barrier. With the source at the focus of the parabola, the reflected pulse is straight. With a straight pulse incident on a parabolic barrier, all parts of the reflected pulse converge at the focus. A circular pulse is also generated at the focus of a semi-circular barrier, and the reflected pulse shows distortion from the spherical aberration. The difference in the shape of the barriers is shown by superposition. B & W, 3 min. 35 sec.
| REFLECTION OF WAVES IN A SPRING: Free End and Fixed End | |
No description available
| REFRACTION OF WAVES | |
Educational Services Incorporated (E.S.I)
This loop shows how wave velocity and wavelength decrease as a wave crosses the boundary from deep to shallow water. When a periodic wave is incident at an angle to the boundary, wave fronts bend. When the angle of incidence (θi) is increased to a critical angle, the refracted waves run parallel to the boundary. With a further slight increase in θi, the wave is totally reflected. B & W, 2 min. 20 sec.
| RETROGRADE MOTION: Geocentric Model | |
The kind of motion a planet undergoes in the Ptolemaic system is clearly demonstrated, along with the way retrograde motion looks. A large "epicycle machine" is used as a model of the geocentric system. The motion of a planet is viewed from various frames of reference: both from above - the stars - and from the center - the earth. Color, 3 min. 35 sec.
| RETROGRADE MOTION: Heliocentric Model | |
A large heliocentric model shows an Earth globe and a Mars globe moving in concentric circles around a Sun globe. Then a camera eye replaces the Earth globe so that the motion of Mars relative to the Earth can be studied. The student views the retrograde motion of Mars as seen from the moving earth. Comparison of the heliocentric with the geocentric model does not give obvious grounds for choosing one model over the other. Color, 3 min. 20 sec.
| REVERSIBILITY OF TIME | |
One's sense of the direction of time is challenged by the camera's ability to reverse direction. From viewing a group of increasingly complex physical events both in forward and in reverse directions, the student is placed in the interesting position of questioning the "natural order" of events. He is brought in contact with one of the most exciting and controversial issues in physics. The reversibility of time can be introduced in discussing the philosophical foundation for Newtonian mechanics, the principle of entropy, and the new Feynman space-time view of quantum electrodynamics. Color, 3 min. 30 sec.
| ROTATING REFERENCE FRAMES | |
H.F. Meiners: Rensselaer Polytechnic Institute
A small cart moving at constant velocity, spraying four paint dots a second, passes across a wheel rotating at constant velocity. The paint dots on a white rectangle placed to the left of the wheel record the motion of the cart as seen by an observer in the laboratory frame; the dots on the wheel describe the motion of the cart as seen by an observer at the center of the wheel in the rotating frame. Analysis of this setup shows how the inertial and non-inertial frames of reference, centripetal forces, centrifugal or pseudo-forces, and Coriolis force can be recognized. Color, 3 min 40 sec.
| RUTHERFORD SCATTERING | |
The scattering of alpha particles by a nucleus is simulated on a cathode-ray tube with a computer. Rutherford's scattering experiment is performed in reverse by using the atom to describe the paths of charged particles moving close to it. The paths of the particles are marked as dots on the screen which indicates their velocities. The total scattering picture slowly builds up as more and more particles are shot at the nucleus. The kinds of orbits possible under a repulsive inverse-square force become apparent. Color, 3 min. 50 sec.
| SAND PENDULUM 3: Drawing Lines on a Tracing Table | |
A sine curve is produced by a pendulum swinging perpendicular to the direction of motion of a moving table. Color - 4 min.
| SCATTERING IN ONE DIMENSION: Part 1 -- Barriers | |
Education Development Center (E.D.C.)
This computer-animated sequence shows the time development of a Gaussian wave packet as it moves into and out of the region of a finite square-potential barrier. The reflection from the barrier and the penetration into or through the barrier are shown for incident particle energies equal in magnitude to (a) one-half the barrier height, (b) the barrier height, and (c) twice the barrier height. B & W, 3 min.
| SCATTERING IN ONE DIMENSION: Part 2 -- Square Wells | |
Education Development Center (E.D.C.)
This computer-animated sequence shows the time development of a Gaussian wave packet as it moves into and out of the region of a finite square-potential well. The reflection from the well and the transmission through the well are shown for incident particle energies equal in magnitude to: (a) one-half the well depth (b) the well depth, and (c) twice the well depth. B & W, 2 min. 40 sec.
| SCATTERING IN ONE DIMENSION: Part 3 -- Edge Effects | |
Education Development Center (E.D.C.)
This computer-animated sequence shows the time development of a Gaussian wave packet as it moves into and out of the region of a potential well; the sharpness of the edges of the well are varied. The behavior of the wave packet is shown for three well shapes: (a) sharp edges and infinitely steep walls; potential has zero surface thickness; (b) rounded edges and slightly sloped walls; 90% to 10% falloff distance is about 1/8 the well width, or a thin potential surface; (c) gently varying well shape; 90% to 10% falloff distance is about 1/4 the well width, or a thick potential surface. B & W, 4 min.
| SCATTERING IN ONE DIMENSION: Part 4 -- Momentum Space | |
Education Development Center (E.D.C.)
This computer-animated sequence shows the time development of a Gaussian wave packet in two representations: configuration space and momentum space. In each representation the same wave packet moves into and out of the region of a finite square-potential well. In each case, the energy of the packet is equal to one-half the well depth. The event in configuration space is shown first, then the same event in momentum space, finally a simultaneous comparison of both representations is made. B & W, 3 min.
| SHADOW OF A HOLE (Optics) | |
No description available.
| SIMPLE HARMONIC MOTION: Reference Circle | |
No description available
| SIMPLE HARMONIC MOTION: The Stringless Pendulum | |
Dr. J.L. Stull: Alfred University
A 5-meter track is curved to produce a gravitational potential energy well. The glider oscillates in simple harmonic motion. Riser blocks are inserted to incline the track and the new equilibrium position of the glider is measured by the method of swings. Thus, the radius of curvature of the track can be calculated. The period of the glider's oscillation is also measured, allowing g to be calculated. Finally, a small sphere and a test tube containing liquid are placed on top of the moving glider to illustrate non-inertial frames of reference. Color, 3 min. 20 sec.
| SINGLE SLIT DIFFRACTION | |
Educational Services Incorporated (E.S.I)
Initially, wavelength (λ) is approximately equal to slit width. Holding the slit width constant, λ is decreased to 1/4 its initial value and then restored. Next, holding λ constant, the slit width is increased. The positions of the nodes and maxima in the diffraction pattern depend on both variables. B & W, 3 min. 20 sec.
| STANDING E.M. WAVES | |
No description available.
| STANDING WAVES ON A STRING | |
Change of tension on a string vibrating continuously at 72 vibrations per second results in standing waves due to reflection from a fixed end. As the tension is changed, the student can see many wave patterns. The string vibrates successively in one, two, three, four and more segments. Nodes and anti-nodes are clearly discernable. A stroboscopic illumination reveals in slow motion the string going through its complete cycle of vibration. Color, 2 min. 35 sec.
| STRAIGHT WAVE REFLECTION FROM STRAIGHT BARRIERS | |
Educational Services Incorporated (E.S.I)
Single straight pulses are reflected from a straight barrier placed parallel to the wave front. The pulses are reflected straight back. The barrier is then placed at various angles to the incident wave front to show that the angle of incidence equals the angle of reflection. The action is frozen and the angle superimposed for emphasis. Then, a continuous periodic wave is reflected from a 45o barrier, and the reflected wave moves off at right angles to the direction of the incident wave. B & W, 3 min. 35 sec.
| SUPERPOSITION | |
On a cathode-ray tube, two sine waves are displayed together with their resultant superposition. The sine waves are changed in phase, frequency, and amplitude to produce changes in the resultant wave. The simultaneous display of the separate waves and of their resultant clarifies the addition of displacements as the fundamental process in superposition. Color, 3 min. 5 sec.
| SUPERPOSITION OF PULSES | |
Educational Services Incorporated (E.S.I)
Single pulses are generated from two sources and the paths taken by the intersection of both pulses are superimposed. Pulses are first generated simultaneously. Then, the right-hand pulse is progressively delayed, and the intersection path bends increasingly to the right. Multiple pulses from two sources are then shown. These build up to periodic waves, and an interference pattern is seen. B & W, 3 min. 25 sec.
| TACOMA NARROWS BRIDGE COLLAPSE | |
Dr. F. Miller, Jr.: Ohio State University
This spectacular loop shows the vibrations which led to the weakening and subsequent collapse of the Tacoma Narrows Bridge, only four months after its opening. Clear pictures, from all sides, are shown of the bridge vibrations during its last few hours, and a detailed discussion of the likely cause of the collapse is given in the film notes. After elimination of faults in the design, a new bridge was built on the original anchorages and tower foundations. Color, 4 min. 5 sec.
| UNUSUAL ORBITS | |
The National Film Board of Canada
In this film we use a modification of the computer program described in the notes for "Central Forces - Iterated Blows". The forces are still central, always directed toward or away from one point, but they are no longer inverse-square forces. 3 min. 25 sec.
| VELOCITY AND ACCELERATION IN CIRCULAR MOTION | |
Educational Services Incorporated (E.S.I)
This loop simultaneously examines the displacement, acceleration and velocity of a spot moving in circular motion on an oscilloscope screen. The acceleration vector leads the velocity vector by 90o, and the velocity vector leads the displacement vector by 90o. Velocity is shown to depend not on the size of the displacement, but on the rate of change of displacement. B & W, 3 min. 5 sec.
| VELOCITY AND ACCELERATION IN FREE FALL | |
Educational Services Incorporated (E.S.I)
A spot on an oscilloscope screen moves vertically up and down. Velocity and acceleration vectors are displayed along with the spot's displacement. The acceleration vector is seen not to change. This Film-Loop introduces the idea that acceleration depends on force acting on a body and allows comparison between constant acceleration vector in free fall and constant downward pull of gravity. B & W, 1 min. 55 sec.
| VELOCITY AND ACCELERATION IN SIMPLE HARMONIC MOTION | |
Educational Services Incorporated (E.S.I)
Displacement, velocity and acceleration are examined simultaneously for a spot moving in simple harmonic motion on an oscilloscope screen. This loop should be compared with its companion loop, "Velocity and Acceleration in Circular Motion", B & W, I min. 15 sec.
| VELOCITY IN CIRCULAR AND SIMPLE HARMONIC MOTION | |
Educational Services Incorporated (E.S.I)
A spot moving clockwise and then counterclockwise in a circle is compared to its velocity vector. A spot moving in simple harmonic motion is treated similarly. B & W, 2 min. 20 sec.
| THE VELOCITY VECTOR | |
Educational Services Incorporated (E.S.I)
This is the introductory loop in a six loop set. It introduces procedures and methods used throughout the series. In this loop, a movable spot is established on an oscilloscope screen. A computer measures the speed and direction of the spot and displays this information on the screen in the form of an arrow - the velocity vector. B & W, 2 min. 40 sec.
| VIBRATIONS OF A DRUM | |
In many finite physical systems, we can generate a phenomenon known as standing waves. A wave in a medium is reflected at the boundaries. Characteristic patterns will sometimes be formed, depending on the shape of the medium, the frequency of the wave and the material. At certain points or lines in these patterns there are no vibrations, because all the partial waves passing through these points just manage to cancel each other out, through superposition.
| VIBRATIONS OF A WIRE: The Triumph Of Mechanics | |
No description available.
| WAVE PACKETS IN PERIODIC POTENTIALS PACKET INCIDENT ON A CRYSTAL | |
No description available
| THE WILBERFORCE PENDULUM | |
Dr. F. Miller. Jr.: Ohio State University
Simple harmonic motion, potential and kinetic energy, and translational and tortional motion are all demonstrated by means of a Wilberforce pendulum. At first, translational vibration and then rotational vibration are demonstrated separately with frequencies determined by the mass and moment of inertia, respectively. The system is then altered so that resonance occurs when the oscillations have a common frequency. The energy exchange between the two degrees of freedom is then apparent as the system adjusts itself to vibrate in one mode and then in the other. Color, 4 min. 25 sec.
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| © | St. Lawrence University | Department of Physics |
| Revised: 25 Jun 03 | Canton, NY 13617 |