- Видео 37
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Williams College Physics
Добавлен 23 мар 2020
Lasers! High voltage! Explosions! Welcome to the Williams College Physics Channel, where you'll find videos used in the labs, demonstrations, and lectures of our Department. Enjoy!
Holographic Interferometry
Use holography to make an interferometric motion detector!
(apologies for the atrocious sound quality)
A hologram can record a near-perfect 3-D image of a real object. When this image is played back exactly on top of the object itself you see two images simultaneously, the recorded one and the real one. You can see fringes (light and dark lines) showing how the light rays from the two images interfere with each other. Each fringe cycle, from dark band to light and then back to dark, represents one additional wavelength of displacement between the two images.
This plate can also be made to vibrate by driving it with a small speaker. As the amplitude of the sound increases, the only part of th...
(apologies for the atrocious sound quality)
A hologram can record a near-perfect 3-D image of a real object. When this image is played back exactly on top of the object itself you see two images simultaneously, the recorded one and the real one. You can see fringes (light and dark lines) showing how the light rays from the two images interfere with each other. Each fringe cycle, from dark band to light and then back to dark, represents one additional wavelength of displacement between the two images.
This plate can also be made to vibrate by driving it with a small speaker. As the amplitude of the sound increases, the only part of th...
Просмотров: 300
Видео
Magnus Effect
Просмотров 22 тыс.4 года назад
Propelling a cart by rotating a cylinder in the presence of an air current.
Cavity Stability
Просмотров 1,4 тыс.4 года назад
Part 4 of the HeNe Laser lab. For a laser cavity to be stable, the light must be able to make many round trips through the gain medium without escaping. By changing the spacing of the mirrors, we go from a stable cavity configuration to an unstable one.
HeNe Modes
Просмотров 7264 года назад
Part 2 of the HeNe Laser lab. Usually a laser is adjusted to produce just the lowest order or Gaussian mode. By using a tube with a wider-than-normal inside diameter and adjustable mirrors, we can observe some of the higher-order modes.
Phase Measurement
Просмотров 4934 года назад
Part 3 of the HeNe Laser lab. Once the laser is oscillating in a 2-lobe pattern, we use a double slit to investigate the phase relationship between the two lobes. If the lobes are in phase with each other, the double-slit pattern should have a central maximum, and if they are out of phase it should have a central minimum.
HeNe Setup
Просмотров 8674 года назад
Part 1 of the HeNe laser lab. A laser consists of a gain medium, where light can be amplified by stimulated emission, and mirrors to form a cavity where light can be bounced back and forth through the gain medium. Initially, the laser gain tube has glass windows mounted at Brewster's angle (to eliminate reflective losses for one light polarization) but no mirrors. External mirrors are added to ...
Surface Tension
Просмотров 2 тыс.4 года назад
Demonstrating surface tension with a loop of thread. A loop of thread is floating on the surface of a bowl of water. The surface tension inside and outside of the loop are the same, and the loop is limp. But what happens if I put a drop of soap inside the loop? The surface tension inside the loop decreases, but the surface tension outside is initially unchanged. There's an unbalanced force pull...
Tesla Coil
Просмотров 804 года назад
The Tesla coil produces high-frequency pulses using driven resonant circuits and transformers. These pulses are very short, like a "click," and can be switched on and off electronically. If it is set to produce 400 pulses per second, for example, your ear perceives this as a 400 Hz tone, and not just a series of clicks. The coil can be programmed to play back a recorded tune, or connected to a ...
Galton Machine
Просмотров 2014 года назад
A Galton machine drops particles onto a series of pins, where the particle can fall either to the left or the right at each pin. After encountering several layers of pins, the particles are collected in bins at the bottom. The distribution of the particles approximates a Normal (Gaussian) Distribution.
Cloud Chamber
Просмотров 954 года назад
A cloud chamber containing cooled alcohol vapor shows trails of microscopic alcohol droplets condensing along the paths of charged subatomic particles. The radioactive source is the isotope Pb-210 painted onto a needle, generating both alphas (fat trails) and betas (thin trails).
Inertial Pizza Pan
Просмотров 394 года назад
Four rubber balls are stacked on top of a pizza pan, placed directly over four water glasses. When the pizza pan is given a sideways shove, it moves sideways, but the balls remain still because of their inertia. High-speed video captures the result in slow motion.
Shattering Glass
Просмотров 6154 года назад
A glass is excited at resonance using sound waves. High-speed video shows the distortion of the glass. The amplitude of the motion grows until the glass shatters violently.
Adiabatic Compression
Просмотров 4 тыс.4 года назад
When air is rapidly compressed it heats up. In this case, the air is heated enough to ignite some cotton fibers in the bottom of the tube.
Adiabatic Bounce
Просмотров 2,2 тыс.4 года назад
A piston in a tight-fitting tube bounces adiabatically on a trapped volume of air.
Chladni Plate
Просмотров 1,3 тыс.4 года назад
A metal plate is sprinkled with sand and driven with a speaker at the center. The sand collects on the parts of the plate that aren't moving, displaying a 2-dimensional standing wave pattern.
Cool demonstration of interferometric holography, Ive seen some great double pulse interferograms at Lake Forest College and of course I've made a few interference hologram myself for fun. Sometimes it wasn't always intentional ;)
Is that the same technology which is used in fighter jet “glass sights”?
Yes a hologram can be used as a HUD and one of the earliest applications in research for DCG holograms was use in Jet fighters HUD's.