tag:techtv.mit.edu,:Array/185826000 2009-04-16 11:06:25 -0400 MIT Department of Physics Technical Services Group A laser is directed at an adjustable single slit and then a pinhole and the resulting diffraction patterns can be seen on a screen. <br><br> A laser directed at two slits spaced closely next to each other creates an interference pattern within the diffraction pattern. Shining lasers of different wavelength light shows how the wavelength affects the interference and diffraction patterns. 146 tag:techtv.mit.edu,:Array/185771040 2009-05-27 11:18:37 -0400 MIT Department of Physics Technical Services Group Rubbing the rim of a wine glass with a wet finger will cause it to resonate at its resonant frequency. The glass is placed in front of a speaker playing a sine wave, created by the function generator, of this same frequency. When the amplitude is turned up, we can see by shining a strobe light at the glass that this resonant frequency causes it to oscillate. When the glass becomes too stressed, it will shatter, which we see very clearly on high speed video. <br><br> A few things to note: The scrolling effect seen in the strobe light footage is caused by interference between the strobe light frequency and the video camera frame rate. Also, the real oscillations of the glass are much faster than they appear in the strobe footage. Setting the frequency of the strobe light can make them appear much slower so that we can see the oscillations in real time without the help of high speed video. <br><br> We would like to thank Dr. Jim Bales of the MIT Edgerton Center for helping us with the high speed video recording, and for the use of the equipment. The high speed camera used here is a Phantom v7.1, donated by the manufacturer Vision Research, Inc. 154 tag:techtv.mit.edu,:Array/185698700 2009-06-30 14:12:10 -0400 MIT Department of Physics Technical Services Group A wire frame is dipped in bubble solution and placed in front of a speaker. At certain frequencies, the soap film oscillates in symmetrical patterns called <a href="http://en.wikipedia.org/wiki/Normal_mode">normal modes</a>.<br><br> A light is reflected off the soap film through a lens onto the wall to show these normal modes as the frequency of the function generator is increased. The first set of normal modes occur at frequencies lower than we can hear with our ears, which is why you can't hear the speaker in the video until the frequency is increased. 268 tag:techtv.mit.edu,:Array/185630620 2009-07-07 11:45:24 -0400 MIT Department of Physics Technical Services Group A long beaded chain is looped over a motor pulley. When the motor is turned on, a disturbance in the chain causes waves to propagate through it. When the motor is brought up to full speed and the chain is knocked off the pulley it will maintain its shape for a few seconds and appear to "walk". 87 tag:techtv.mit.edu,:Array/185603080 2009-07-20 22:08:32 -0400 Center for Advanced Visual Studies A dialog (in speech and sign) between artists, designers, scientists, students, speakers, and signers. Participants touch on the range of human experience including deafness, and on acoustical engineering, especially resonance and sonic vibrations. All presentations are interpreted in American Sign Language. At the center of the conference is a specially-built raised floor, designed to be activated with low-frequency vibration. By sitting, standing, lying on the floor, hearing and deaf participants are able to experience sound through their bodies. During the conference, presenters use the floor as a vehicle for tactile communication. Ben Bahan, a professor at Gallaudet University, speaks about the sensory reach of deaf people. 1094 tag:techtv.mit.edu,:Array/185568200 2009-07-21 15:23:29 -0400 Center for Advanced Visual Studies A dialog (in speech and sign) between artists, designers, scientists, students, speakers, and signers. Participants touch on the range of human experience including deafness, and on acoustical engineering, especially resonance and sonic vibrations. All presentations are interpreted in American Sign Language. At the center of the conference is a specially-built raised floor, designed to be activated with low-frequency vibration. By sitting, standing, lying on the floor, hearing and deaf participants are able to experience sound through their bodies. During the conference, presenters use the floor as a vehicle for tactile communication. Ben Bahan, a professor at Gallaudet University, speaks about the sensory reach of deaf people. 754 tag:techtv.mit.edu,:Array/185512140 2009-07-21 15:46:49 -0400 MIT Department of Physics Technical Services Group A ripple tank is placed above a mirror and a projection screen. Two synchronous point sources, whose frequency can be varied, tap the surface of the water and produce circular waves. The interference pattern of the waves including the lines of nodes can be observed on the screen. 102 tag:techtv.mit.edu,:Array/185466860 2009-07-21 16:21:23 -0400 Center for Advanced Visual Studies A dialog (in speech and sign) between artists, designers, scientists, students, speakers, and signers. Participants touch on the range of human experience including deafness, and on acoustical engineering, especially resonance and sonic vibrations. All presentations are interpreted in American Sign Language. At the center of the conference is a specially-built raised floor, designed to be activated with low-frequency vibration. By sitting, standing, lying on the floor, hearing and deaf participants are able to experience sound through their bodies. During the conference, presenters use the floor as a vehicle for tactile communication. 803 tag:techtv.mit.edu,:Array/185438220 2009-07-21 16:55:50 -0400 Center for Advanced Visual Studies A dialog (in speech and sign) between artists, designers, scientists, students, speakers, and signers. Participants touch on the range of human experience including deafness, and on acoustical engineering, especially resonance and sonic vibrations. All presentations are interpreted in American Sign Language. At the center of the conference is a specially-built raised floor, designed to be activated with low-frequency vibration. By sitting, standing, lying on the floor, hearing and deaf participants are able to experience sound through their bodies. During the conference, presenters use the floor as a vehicle for tactile communication. Designer, musician, and artist, Eric Gunther speaks about his recent projects with sound and vibration. 881 tag:techtv.mit.edu,:Array/185415440 2009-07-22 11:09:55 -0400 MIT Department of Physics Technical Services Group A ripple tank is placed above a mirror and a projection screen. A horizontal bar, whose frequency can be varied, taps the surface of the water and produces plane waves. The waves are incident on a barrier containing an adjustable opening. <br><br> With a narrow single slit opening we see a plane wave emerge as a spherical wave on the other side of the barrier. This can be explained by the <a href="http://en.wikipedia.org/wiki/Huygens_principle">Huygens-Fresnel principle</a> which states that each point in the slit forms its own spherical wavefront source. With a wider slit, more point sources arise, causing interference patterns due to the larger angles involved with a broader spatial distribution of these sources. 186