Physics and Astronomy Demonstration Resources

SECTION D - Description of Film Loops

( 8 mm Film Loops )

FL1. Atomic, Nuclear and Quantum Physics

1.01 ..... Sodium D line reversal, absorption spectra of Hemoglobin and Oxyhemoglobin and Didymium Glass are shown with a constant deviation spectrometer.

1.02 ..... A ball of unknown mass and Velocity is collided with a pair of balls of known masses. From the recoil velocities and angles the mass of the incoming particle may be determined. This is supposed to be a model of Chadwick's experiment in which the Neutron was discovered.

1.03 ..... Filmed in real time, this shows a vial of ether cooling from above to below the critical temperature, with the characteristic appearance of the liquid/gas interface.

1.04 ..... An iron whisker is covered with magnetite in order to make visible the domain walls. The sample is then subjected to fields of various strengths and the motion of the domain walls is shown. When subjected to an intense field, the domains are seen to become unstable.

1.05 ..... Liquid oxygen is poured over the poles of a strong magnet, and is seen to adhere to them. The experiment is repeated with liquid nitrogen to shown that the effect is not due to the low temperatures involved.

1.06 ..... The progressive diminition in the number of counts detected by a scintillation spectrometer placed in front of samples of Cu64 and Mn 56 is shown by time lapse photography. From this data, the half-lives of the two samples can be calculated.

1.07 ..... Shows assembly of a scintillation detector, Gamma spectrum of Mn56 with increasing statictical accuracy, and the photopeak, Compton edge and backscatter regions of the detectors characteristics.

1.08 ..... A zinc plate mounted on an electroscope is charged and then illuminated with an ultraviolet source. The electroscope is seen to discharge with negative charge on it, and not discharge with positive. The ultraviolet portion of the illumination is removed and the device is seen not to discharge. A dirty zinc plate is also seen to hold its charge.

1.09 ..... A computer simulation of an alpha particlescattering off a gold nucleus with varying immpactparameter is shown.

1.10 ..... Elastic and Plastic deformations of a metal crystal and dislocations are modelled using a raft of soap bubbles. During elastic deformation, the planes are seen to deform, but not dislocate with respect to one another. During Plastic deformation, permanent slippage of the planes is seen.

1.11 ..... The crystalline structure of a metal is demonstrated and modeled with a 2 dimensional array of bubbles. The boundaries between different 'crystals' is shown.

1.12 ..... A computer simulation of a Gaussian wave packet is shown, spreading out as time increases. The rate of spreading is seen to depend on the initial width of the packet.

1.13 Shows the periodic time dependance of a wave packet confined in an infinitely deep square well potential.

1.14 ..... Shows time development of a Gaussian wave packet as it moves into and out of a region of a finite square potential barrier for incident particle energies of ½, 1,and 2 times barrier height.

1.15 ..... Shows time development of a Gaussian wave packet as it moves into and out of the region of a finite square potential well for incident particle energies ½, 1 and 2 times well depth.

1.16 ..... Shows time development of a Gaussian wave packet as it moves into and out of the region of a finite potential wells of variable edge sharpness.

1.17 ..... Shows Gaussian wave packet in configuration and momentum spaces as the packet moves into and out of a finite square potential well, with the energy of the wave packet equal to half the well depth.

1.18 ..... Illustrates motion of a Gaussian wave packet through a crystal when k lies in one band only, then in two bands.

1.19 ..... Shows a free space Gaussian packet incident on a crystal.

1.20 ..... Propogation through a lattice when one cell is anomalous.

FL2. E and M

2.01 ..... After drawing sparks from the terminal of the generator, the machine is taken apart and the charges on the various parts of the device are shown. With the sphere removed, little charge can be built up at the top of the machine.

2.02 ..... The classic experiment to show that charges reside on the outer surfaces of conductors is performed.

2.03 ..... The attraction and repulsion of a suspended metallized sphere as the sphere is charged by contact and induction are shown.

2.04 ..... Shows effect on a capacitor in varying plate size, plate separation, dielectric.

2.05 ..... Electric monopoles exist, but magnetic ones are (at the very least) uncommon. Down to atomic level magnetism seems inherently dipolar.

2.06 ..... Steady currents in various shaped conductors produce different B fields.

2.07 ..... Forces on a small magnetic dipole in uniform and non-uniform B fields.

2.08 ..... Illustrates how B varies with number of turns and current flow.

2.09 ..... Illustrates that relative motion leads to induced emf, effect of two "bucking" voltages.

2.10 ..... Illustrates emfs produced by variations in flux. Animated field lines resulting from charge motion.

FL3. Kinetic Theory of Gases

3.01 ..... The diffusion of 1. set of small pucks placed at one side of an air table, 2. Heavier pucks of same size in a field of lighter ones, and 3. Larger more massive pucks in a field of smaller ones is shown. Also shown is an experiment wherein pucks are removed as they diffuse to the opposite side of the table and replaced at the starting side. A histogram of the density gradient is produced.

3.02 ..... The velocity distribution for a set of small pucks is presented in the form of a histogram, and the histogram for a set of larger pucks is produced. The rms speed is found to be lower, as expected. A set of even larger pucks is introduced to allow the students to calculate this rms speed.

3.03 ..... Pucks are placed on an inclined air table to simulate the atmosphere of earth. The distribution of the pucks as a function of temperature is shown, as is the effect of introducing a number of larger pucks.

3.04 ..... The velocity distribution of a set of pucks on an air table is measured and found to conform to the Maxwellian velocity distribution curve.

3.05 ..... Pressure as the force/unit length on the walls of the air table is shown, and the effect of No. of pucks and wall vibration rate ('temperature') on this force demonstrated. Isothermal and adiabatic Compression and Expansion are modeled.

3.06 ..... The motion of an individual puck in a field of others is photographed, and a histogram of the free path constructed, which is found to conform roughly to the theoretical predictions. A very massive puck is introduced and is used to model Brownian motion.

FL4. Mechanics

4.01 ..... Plots are made of displacement, velocity and acceleration vs time for a car as it moves along a track.

4.02 ..... This computer generated sequence shows a particle moving with and without a force acting on it. The force varies. The velocity of the particle is indicated by dots generated at equal time intervals along the part of the particle.

4.03 ..... Part I. A bowling ball is dropped and photographed with a high-speed camera. Scales are placed along the path of the ball to allow data to be taken.

4.04 ..... Part II. A bowling ball is dropped and photographed at high speed. Scales are set such that the velocity of the ball can be measured at 4 distances below the release point.

4.05 ..... An inclined air table is used to show the relationship of x & y motions for a puck inscribing a parabolic trajectory. The Monkey and the Hunter demonstration is performed on the apparatus, and the range of a launched puck for variable angle of launch shown.

4.06 ..... The motion of the centre of mass of a pair of pucks on the air table is shown as the pucks move at constant velocity and increasing velocity on an inclined table.

4.07 ..... A rotor is used as an accelerated reference frame photographs being taken with a camera both outside and inside the rotor. From the point of view of the camera inside, gravity acts downwards and outwards, as indicated by a ball that no longer hangs vertically with the rotor turning.

4.08 ..... The apparent increase and decrease in the weight of a student in an elevator as the elevator accelerates upwards and downwards is shown. At constant velocity, the students weight is normal.

4.09 ..... A car moving at constant velocity makes marks on a rotating disc as it goes past. To an observer on the disc, the car must be subjected to some force as both the magnitude and direction of its velocity appear to change.

4.10 ..... Elastic and Inelastic collisions are contrasted, then measurements are made of equal and unequal mass elastic collisions. For the unequal mass collisions, a small mass is collided with a larger and vice versa.

4.11 ..... A number of inelastic collisions are performed on the air track and time/unit length measured. Conservation of momentum can be deduced from the data. Two cars of equal mass, but opposite velocities are collided.

4.12 ..... Displacement vs time records are taken for a pair of pucks connected by a light rod when the system is struck with a ball of known momentum first at the centre of mass, and then to one side of the C of M. Conservation of linear and angular momentum may be deduced from the data.

4.13 ..... The velocities of a car on the air track (from which the energy can be calculated) are measured for the three cases of the car being accelerated first by a falling weight, second by having the track inclined and finally by having a spring push the car. In each case the data needed to calculate to force on the car is given.

4.14 ..... Two dimensional collisions are shown on the air table. Equal and unequal mass collisions are shown for the elastic case, and a lossycollision is presented.

4.15 ..... Computer simulation of a car moving on a road, and the plot of x vs t. Shown method of measuring average velocity and the dependance of this on time interval used in measurement. Shows effect of taking progressively smaller time intervals.

4.16 ..... Shows the determination of the position of a particle from the area under the velocity curve, with the effect of an initial displacement indicated.

4.20 Animation of a spot moving vertically in simple harmonic motion, with its displacement, velocity and acceleration being displayed simultaneously.

4.21 ..... A spot moves in a circle at several different speeds with its velocity vector being shown. The spot then moves in simple harmonic motion, again showing the velocity vector.

4.22 ..... A spot moves in circular motion and its displacement, velocity and acceleration are examined simultaneously. The phase relationship of the three vectors is pointed out.

4.23 ..... Missing.

4.24 ..... Two views are presented of a pair of bodies rotating around their centre of mass. The bodies attract each other with an inverse square force. The first view is of the system rotating and translating and is seen to be quite complicated. In the second view, taken from a point moving with the centre of mass, the orbits are closed and simple.

4.25 ..... This computer generated sequence shows the behavior of two bodies attracted to each other by a force varying as the positive power of R. The force vectors are shown.

4.26 ..... As in 4.25, except having forces that vary as the negative power of R.

4.27 ..... Shows the setup and operation of the Leybold torsion balance for the measurement of "G". Time lapse photographs is used to speed up the experiment, and the data necessasry to calculate "G" is given.

4.28 ..... Shows a time-lapse film of the orbit of Io. The elliptic nature of the orbit is very apparent. Film also shows pole flattening of Jupiter due to its rotation.

4.29 ..... Computer simulation shows the motion of 2 'planets' rotating about the 'sun' being directed by an inverse square law force. By stopping the film and taking a set of data, the laws of Kepler may be determined.

4.30 ..... A ball dropped from the mast of a moving ship is filmed in slow motion, and is seen to strike the water directly under the release point. The ball is then knocked of a stationary stand by the person on the ship, and is seen to strike the water behind the ship. Finally, the ball is picked up from the stationary stand, held for a short while and then released. This time it is again seen to hit the water under the release point.

4.31 ..... A flare is dropped from an aircraft moving at constant velocity, and is seen to stay directly under the craft for nearly the entire time it is falling. Wind resistance causes a small lag.

4.32 ..... A projectile is fired vertically from a moving snowmobile and is seen to land back on the launcher so long as the vehicle moves with constant velocity. When the snowmobile accelerates or decelerates, the projectile misses the launcher. Equally spaced lights along the path of the vehicle give a reference for velocities.

4.33 ..... A boat moving at constant speed moves upstream, downstream, directly across and at an angle to a river whose water presumably moves with constant velocity also. The differences in velocities for the 4 cases are apparent. The angle of the velocity vector of the boat in the last case is such that the boat moves in a straight line from bank to bank.

4.34 ..... Two cars collide and are photographed firstly with a stationary camera at the position of the stationary car; secondly, with the camera moving with and at the same velocity as the moving car; and thirdly with the camera moving ahead of and slower than the moving car. All collisions are equal mass elastic. The method of photographing the events is shown and the experiments repeated with a reference object placed at the position of the stationary car.

4.40. Two equal length pendulums are set oscillating and then coupled and made to oscillate. The energy transfer between the two is seen. Coupled sand pendulums are then used to plot the amplitudes of oscillation of the two.

4.41 ..... The two normal modes of oscillation for a two equal mass coupled oscillator are shown and the frequencies measured. A mixed mode is also shown.

4.42 ..... The behavior of two normal modes of two coupled pendulums is shown. Other pendulums are set to oscillate at the same frequencies as these modes and are seen to go in and out of phase with a regular beat pattern. When the original coupled system is oscillating in a state that combines both modes, energy is seen to exchange at the same beat rate as seen above.

4.43 ..... This film shows a series of different coupled mechanical oscillators exchanging energy. The frequency of energy exchange is seen to depend on the coupling.

4.44 ..... Two unequal mass cars are used to form a coupled oscillator. The frequencies of the individual cars, with the other fixed, and the frequencies of the two normal modes are measured. A mixed mode is shown.

FL5. Optics

5.01 ..... The dependance of the separation of the maxima in a double slit experiment on the separation of the slits and the wavelength of the light is shown.

5.02 ..... The dependance of the width of a single slit patterns width as the width of the single slit and the wavelength of the illuminating light are varied is shown. Also shown in ripple tank film loop 6.12.

5.03 ..... A Michelson interferometer is illuminated with Sodium light and the effects of mirror angle and position are shown. White light fringes are produced, and a thin film is inserted into the path, with a subsequent fringe shift. A Mach-Zehnder interferometer is shown.

5.04 ..... A pinhole is viewed from a distance with a telescope whose aperture is variable. The Airy disk is shown and the size of the disk is seen to change as the aperture is varied. Two pinholes are then viewed through a number of different apertures and then the progressive merging of the two as the aperture of the telescope is decreased is shown.

5.05 ..... Shows how vector addition of waves of the same amplitude but different phases can produce a multiple slit interference pattern.

FL6. Waves

6.01 ..... A wide channel of deep water between two shallow regions in a ripple tank acts as a barrier to a wave from one of the shallow regions. The incident wave appears totally reflected. As the channel is narrowed, reflection decreases and transmission increases.

6.02 ..... The reflection of a burst of straight waves from a 2-dimensional lattice of pegs is shown as the wave length and the lattice angle are varied.

6.03 ..... Circular pulse waves are reflected from a straight barrier and the virtual source behind the barrier is shown with animation. Waves are also produced along the major axis of an elliptic reflector. When the source is at one focus, the waves are seen to concentrate at the other.

6.04 ..... The film shows two sequences: firstly the diffraction of a wave around a barrier is shown and the effects of changing the wavelength demonstrated. Secondly a wave is scattered from a small obstacle, and the wavelength increased until there is no obvious disturbance of the wavefront.

6.05 ..... A wave is produced in a ripple tank by a moving source. The doppler effect is clearly seen.

6.06 ..... A two-source experiment is performed in a ripple tank the effects of changing the phase of one source with respect to the other are shown.

6.07 ..... A wave generator moves across a ripple tank at velocities below and above the wave velocity. At the higher velocities, a shock wave is seen to develop, and the cone angle is seen to depend on the velocity ratio.

6.08 ..... A two source interference experiment is performed and the effects of changing the source separation and frequency are demonstrated.

6.09 ..... Two slits are used to show that the interference pattern of waves emanating from the slits is similar to that produced by 2 sources. The narrowing of the interference maxima as the number of slits is increased is shown.

6.10 ..... Circular waves are generated at points along the axis of a parabolic reflector. At the focus, the reflected wave is seen to be straight. A wave reflected from a circular barrier is seen to be distorted. Straight waves directed at the parabolic reflector are seen to converge on the focus.

6.11 ..... Waves are seen to reflect as they traverse a region wherein the wave velocity changes (in this case, a change in depth of the water in the tank). Waves are made to traverse the boundary from either side, and when going from slower to faster, are seen to totally reflect when the incident angle is large enough.

6.12 ..... Single slit diffraction effects as wavelength and/or slit width is varied.

6.13 ..... Single plane waves are seen to reflect from a straight barrier. The angle of incidence is seen to be equal to the angle of reflection.

6.14 ..... Single pulses are generated by two sources, and the point of intersection of the two waves marked as one is delayed with respect to the other. Multiple waves are then generated, and the interference pattern is seen.

6.20 ..... Various modes of oscillation for soap bubbles on circular and rectangular frames are shown.

6.21 ..... The ultimate demonstration of resonance, wherein the Tacoma Narrows Bridge is driven to destruction by the wind is shown.

6.22 ..... Alcohol in Glass thermometers are mounted along the length of a brass bar. The temperature waves produced by heating and cooling one end are seen to travel down the bar, and rapidly die out.

6.23 ..... A single crest water wave, a tidal bore, a shock wave in a crowd of people, an atmospheric shock wave following an H-bomb test and the spreading of light from a Nova are shown to demonstrate the idea of a non-recurrent wave front.

6.24 ..... Wilberforce's pendulum, consisting of a coupled rotational/translational spring-mass oscillator is demonstrated. Energy is seen to exchange between the rotational and translational modes.

6.25 ..... A metal plate, supported at its centre, has sand sprinkled on its surface. The edge of the disk is then bowed, and the resultant standing wave causes the sand to move to the nodes of oscillation. The patterns so produced are called Caladni figures.

6.26 ..... Straight and circular wires are driven at resonance by an electronic oscillator. The various modes of vibration are shown both in real time and slow motion photography.

6.27 ..... A number of symmetric and asymmetric modes of oscillation for a rubber diaphragm driven by a loud speaker are shown. The nodal lines are marked. The motion is photographed with a high speed camera.

6.28 ..... A string is driven by a tuning fork and the effects of tension of the string on the standing wave pattern are shown. Several standing wave patterns are demonstrated.

6.29 ..... The variation in the number of nodes on a vibrating rubber hose as the driving frequency is changed is shown. Also demonstrated is the fact that the standing wave pattern only appears for certain frequencies of drive.

6.30 ..... Missing.

6.31 ..... Two waves and their superposition are displayed on an oscilloscope, and the effect of varying amplitude and phase of the two waves on the sum demonstrated.

6.40 ..... Continuous standing waves are set up in a spring and markers placed at equal separations along the spring. The motion of these markers is noted. Some of the driving frequencies do not corresponnd to resonances.

6.41 ..... Groups of waves are sent down a spring and the temporary standing wave formed by the superposition of the forward and backward waves is seen.

6.42 ..... Longitudinal standing waves are set up in a long spring with markers placed along its length. Some markers are seen to be stationary. Various driving frequencies are used.

6.43 ..... Reflections of transverse pulses in a long spring with either a fixed or free end are shown.

6.44 ..... Two pulses are sent along a long spring and are seen to go through one another. Three identical springs are supported so that one spring shows the first pulse, another the second and the third, the superposition. Two crests, a crest and a trough and a 'bipolar' pulse are generated and the superpositions seen.

6.45 ..... "Positive and "negative" pulses are produced in a long spring in both longitudinal and transverse forms. Wavetrains of both types are also produced.

FL7. Miscellaneous

7.01 ..... Shows the production of vortices spinning off an object which moves at constant speed through a fluid.

7.02 ..... This animated film shows the manner in which sound waves are converted to nerve impulses by the ear.

7.03 ..... Uses high speed photographs to show "crowns", droplets, pedestals that form when a drop encounters a deep fluid or a thin film.

FL8. (Not Used)

FL9. NASA Films of Sky Lab

9.01 ..... Scenes of moving astronauts taken with stationary and moving cameras are contrasted.

9.02 ..... Water bridges are formed between two metal rods and the effects of surface tension pointed out. The bridge system is rotated and the bridge breaks. The effect of separation of the two rods on the curvature of the bridge is shown.

9.03 ..... Large drops of water are allowed to float freely in the skylab. The dumbbell shape that the drop forms into when rotated is demonstrated. The formation of one drop from two is shown.

9.04 ..... Free oscillation of water drops and bridges and a complex Wilberforce pendulum are shown.

9.05 ..... Astronauts are seen to move through the skylab with various degrees of translational and rotational energy.

9.06 ..... Paper planes and darts are thrown in the 'weightless' environment of the skylab. Weightlifting and balancing acts are performed.

9.07 ..... A series of gymnastic maneuvers are performed in a weightless environment.

9.08 ..... The principle of measuring mass by the measurement of the period of a spring-mass oscillator is applied to measuring the mass of an astronaut.

9.09 ..... Collisions between drops of water and astronauts are shown. The first section of the film is filmed in real time, while the second section consists of the first section run in reverse.

9.10 ..... A gyroscope is seen to hang in space and to translate when pushed. The application of a couple causes the angular momentum direction to prescess.

9.11 ..... Air bubbles are formed inside water and soap drops. Soap drops are formed at the ends of 2 rods and a bridge of the solution produced. The bridge is oscillated and rotated and the effects of these motions are shown.

9.12 ..... That momentum is a conserved quantity is dramatically shown in this film. An astronaut starts with 1. translational but no rotational momentum, 2. translational and rotational momenta, and 3. No momentum. Various gyrations are performed, but no changes in the momenta can be produced.