tag:techtv.mit.edu,:Array/186278980 2008-03-14 10:22:28 -0400 MIT Sloan Widely considered the nation's leading expert on aviation safety, Arnie Barnett uses his background in applied math to help conquer his own fear of flying. He calms himself — and sometimes even fellow passengers — during turbulence by recalling statistics on crash probability. A firm believer that math should be accessible to his students and can be applied to almost any problem, Arnie's passion for math is infectious. In this podcast, Arnie talks about his ideas for a new approach to the Electoral College and his constant vigilance against skewed statistics. 2580 tag:techtv.mit.edu,:Array/186033180 2009-01-06 13:23:42 -0500 MIT Department of Physics Technical Services Group A plexiglass rod rubbed with fur picks up a positive electric charge, while a rubber rod rubbed with fur picks up a negative electric charge. When either rod is brought in contact with hanging tinsel, the tinsel becomes charged and flares out. The other rod, however, will now attract the tinsel. Touching the tinsel with your hand discharges it. <br> <br> These electrostatic forces can also be seen with a conducting balloon. Touching a charged rod to the balloon transfers charge, causing the balloon to be repelled away from the rod. <br> <br> The ancient Greeks noticed this phenomenon when rubbing pieces of amber (which pick up a negative electric charge, like our rubber rod). The word "electricity" is based on the Greek name for amber: "elektron." 123 tag:techtv.mit.edu,:Array/185971640 2009-01-14 12:37:06 -0500 MIT Department of Physics Technical Services Group A <a href="http://en.wikipedia.org/wiki/Wimshurst_machine">Wimshurst electrostatic generator</a>, working on the principle of induction, generates high voltage differences and sparks between two movable electrodes. By increasing the distance between the electrodes, higher potential differences can be built up. <br><br> <a href="http://en.wikipedia.org/wiki/Electrostatic_induction">Electrostatic induction</a> refers to the principle that charges in an object (especially a conductor) redistribute themselves in the presence of nearby charges. Opposite charges are attracted to each other, while similar charges are repelled. <br><br> Larger charges can be stored by connecting the knobs to Leyden jars which are component parts of the machine. 151 tag:techtv.mit.edu,:Array/185926380 2009-01-22 15:13:38 -0500 MIT Department of Physics Technical Services Group <a href="http://en.wikipedia.org/wiki/Leyden_jar">Leyden Jars</a>, an early style of capacitor, can be connected to the two electrodes of the Wimshurst Machine. They will store charge as it is generated, giving a much stronger spark across the gap. <br><br> Next we have a three-piece dissectible Leyden Jar consisting of two metal cups separated by a glass cup. When charged with the Wimshurst machine, we see by touching it with the shorting rod that it holds a large amount of charge. However, when disassembled, the metal cups can be brought into contact with each other and no spark will be generated. When the jar is reassembled it can then be discharged. This demonstrates that, in this situation, the charge actually resides on the surface of the glass (a <a href="http://en.wikipedia.org/wiki/Dielectric">dielectric</a>), not on the metal. 175 tag:techtv.mit.edu,:Array/185788240 2009-06-10 14:04:53 -0400 MIT Department of Physics Technical Services Group Two pucks of the same mass are slid at each other on an air table, and their resulting collisions demonstrate conservation of momentum. Notice on the first collision, for example, that when a moving puck hits a stationary puck dead-on, that the second puck leaves with the same velocity as the first, and the first puck stops moving completely. 80 tag:techtv.mit.edu,:Array/185755040 2009-06-18 13:08:48 -0400 MIT Department of Physics Technical Services Group A cart moving at constant velocity shoots a ball straight upwards. Since the ball has the same translational velocity as the cart, it is caught when it comes back down. 68 tag:techtv.mit.edu,:Array/185721720 2009-08-14 14:52:17 -0400 MIT Libraries Part of the MIT Libraries video tutorial series. The life cycle of information is addressed, both in general topics and in scientific fields. Used in 3.091: Introduction to Solid State Chemistry. 187 tag:techtv.mit.edu,:Array/185689500 2009-08-19 11:28:08 -0400 MIT Department of Physics Technical Services Group Two demonstrators sit at either end of a rotating platform and toss a ball back and forth. When viewed from the rest frame (when the camera is mounted to the ground), the ball follow a straight line but doesn't reach its target because during the ball's flight the target rotates away. When viewed from the rotating frame (when the camera is mounted to the rotating platform), the ball appears to experience a force that pulls it away from the target. <br><br> This curved trajectory in the rotating frame is known as the "Coriolis Effect", sometimes called the "Coriolis Force", though it disappears in the rest frame. The Coriolis Effect can be seen in many situations where rotating frames are encountered, especially meteorology and astronomy. Atmospheric systems, for example, often follow circular patterns due to the Coriolis effect. Airplanes and missiles appear to follow curved trajectories when seen by observers on Earth as the planet rotates underneath. 181