http://www.compadre.org/informal/ The latest material additions to the Physics To Go. en-US Copyright 2012, ComPADRE.org editor@physicstogo.org editor@physicstogo.org Tue, 24 Jan 2012 16:42:01 EST http://blogs.law.harvard.edu/tech/rss http://www.compadre.org/portal/services/images/LogoSmallInformal.gif http://www.compadre.org/informal/ 125 35 http://www.compadre.org/informal/items/detail.cfm?ID=11677 This Planetary Society site provides an overview of the five methods of detecting extrasolar planets. The site describes each method and enumerates its advantages and disadvantages. Links provide related information. Astronomy/Exoplanets/Detection Methods http://www.compadre.org/informal/bulletinboard/Thread.cfm?ID=11677 Tue, 24 Jan 2012 16:42:01 EST http://www.compadre.org/informal/items/detail.cfm?ID=11677 http://www.compadre.org/informal/items/detail.cfm?ID=7908 This simulation introduces the search for planets outside of our solar system using the Doppler and transit methods. It includes simulations of the observed radial velocities of singular planetary systems and introduces the concept of noise and detection. In the simulations you can control the stellar and planetary properties and the system orientation. You can then observe how the graph is affected. Instructor resources are available including student manuals, assessment materials, and a list of the assumptions used. This is part of a collection of astronomy applets. Astronomy/Exoplanets/Detection Methods http://www.compadre.org/informal/bulletinboard/Thread.cfm?ID=7908 Mon, 23 Jan 2012 17:10:46 EST http://www.compadre.org/informal/items/detail.cfm?ID=7908 http://www.compadre.org/informal/items/detail.cfm?ID=11674 This APOD page features the first confirmed image of an extrasolar planet orbiting a sun-like star. Text and numerous links provide additional information; one link goes to the press release of the confirmation. Astronomy/Exoplanets http://www.compadre.org/informal/bulletinboard/Thread.cfm?ID=11674 Sat, 21 Jan 2012 15:30:01 EST http://www.compadre.org/informal/items/detail.cfm?ID=11674 http://www.compadre.org/informal/items/detail.cfm?ID=11673 This NASA site provides a description of the Kepler observatory, which searches for extrasolar planets. Text describes how these planets are detected, the mission objectives, and how Kepler works. The site also provides information about the Kepler team and the latest extrasolar planets Kepler has detected. Astronomy/Exoplanets http://www.compadre.org/informal/bulletinboard/Thread.cfm?ID=11673 Fri, 20 Jan 2012 15:47:43 EST http://www.compadre.org/informal/items/detail.cfm?ID=11673 http://www.compadre.org/informal/items/detail.cfm?ID=11597 This article by a physicist and an aeronautical engineer explains the physics of how aircraft wings produce lift. It shows how several popular explanations are clearly wrong, and then accounts for lift in terms of Newton's first and third laws without using calculus. The article also discusses power, drag, angle of attack, and wing vortices. Numerous drawings illustrate the ideas. Fluid Mechanics/Dynamics of Fluids http://www.compadre.org/informal/bulletinboard/Thread.cfm?ID=11597 Wed, 28 Dec 2011 10:53:29 EST http://www.compadre.org/informal/items/detail.cfm?ID=11597 http://www.compadre.org/informal/items/detail.cfm?ID=11596 The activity on this site from Australia's national science agency CSIRO enables visitors to connect two plastic bottles so water will flow from one to the other and produce a vortex. An illustration shows how to construct the connector. Fluid Mechanics/Dynamics of Fluids/Vorticies http://www.compadre.org/informal/bulletinboard/Thread.cfm?ID=11596 Tue, 27 Dec 2011 16:34:18 EST http://www.compadre.org/informal/items/detail.cfm?ID=11596 http://www.compadre.org/informal/items/detail.cfm?ID=11595 This short article from the U.S. Centennial of Flight Commission explains how wingtip vortices form by describing the airflow around a wing. Several diagrams illustrate this airflow. The article also describes how these vortices can pose a hazard for other aircraft. Fluid Mechanics/Dynamics of Fluids/Vorticies http://www.compadre.org/informal/bulletinboard/Thread.cfm?ID=11595 Sat, 24 Dec 2011 10:34:58 EST http://www.compadre.org/informal/items/detail.cfm?ID=11595 http://www.compadre.org/informal/items/detail.cfm?ID=11594 This article in the Smithsonian's Air & Space magazine describes how winglets, short, nearly vertical extensions of the wingtip, improve aircraft performance. The article explains what kind of aircraft benefit from winglets and what trade-offs they create. Other Sciences/Engineering http://www.compadre.org/informal/bulletinboard/Thread.cfm?ID=11594 Fri, 23 Dec 2011 21:47:40 EST http://www.compadre.org/informal/items/detail.cfm?ID=11594 http://www.compadre.org/informal/items/detail.cfm?ID=11573 This article from MIT News describes the surprising patterns that Prof. Markus Zahn and his student Cory Lorentz observed when they placed a ferrofluid sample in a changing magnetic field. The article contained six photographs of these patterns. Electricity & Magnetism/Magnetic Materials http://www.compadre.org/informal/bulletinboard/Thread.cfm?ID=11573 Tue, 29 Nov 2011 11:31:32 EST http://www.compadre.org/informal/items/detail.cfm?ID=11573 http://www.compadre.org/informal/items/detail.cfm?ID=11541 This YouTube video by Sachiko Kodama, "Morpho Towers, Two Standing Spirals," shows a ferrofluid work of art. As music plays, the video shows ferrofluid patterns appearing and changing on two towers as electromagnets inside produce changing magnetic fields. Electricity & Magnetism/Magnetic Materials http://www.compadre.org/informal/bulletinboard/Thread.cfm?ID=11541 Mon, 28 Nov 2011 17:11:45 EST http://www.compadre.org/informal/items/detail.cfm?ID=11541 http://www.compadre.org/informal/items/detail.cfm?ID=11533 This webpage from the National High Magnetic Field Laboratory shows how to make a ferrofluid with readily available materials. In addition, the page links to two videos that show interesting ferrofluid behavior as the magnetic field is increased. Electricity & Magnetism/Magnetic Materials http://www.compadre.org/informal/bulletinboard/Thread.cfm?ID=11533 Wed, 09 Nov 2011 16:54:57 EST http://www.compadre.org/informal/items/detail.cfm?ID=11533 http://www.compadre.org/informal/items/detail.cfm?ID=11532 This page from the University of Wisconsin-Madison Materials Research Science and Engineering Center Interdisciplinary Education Group offers seven videos that show ferrofluid behavior in a magnetic field. QuickTime is required to view the videos. Electricity & Magnetism/Magnetic Materials http://www.compadre.org/informal/bulletinboard/Thread.cfm?ID=11532 Wed, 09 Nov 2011 15:38:02 EST http://www.compadre.org/informal/items/detail.cfm?ID=11532 http://www.compadre.org/informal/items/detail.cfm?ID=11517 This Nature News article describes the evidence for particles--neutrinos--traveling faster than light. The article describes the consequences of this discovery and outlines the reasons for skepticism. Also, it mentions an earlier and less accurate experiment that found a similar result. Relativity/Special Relativity/Relativistic Kinematics http://www.compadre.org/informal/bulletinboard/Thread.cfm?ID=11517 Sat, 15 Oct 2011 14:42:32 EST http://www.compadre.org/informal/items/detail.cfm?ID=11517 http://www.compadre.org/informal/items/detail.cfm?ID=11515 This NOVA website simulates travel to distant stars and back in a spaceship that can move at various percentages of the speed of light. You set the spaceship speed and choose your destination star, and the simulation calculates the time of travel as measured on Earth and inside the spaceship. Text describes the "twin paradox" of the theory of relativity and also the 1971 test of its prediction using airliners and atomic clocks. Relativity/Special Relativity/Time Dilation http://www.compadre.org/informal/bulletinboard/Thread.cfm?ID=11515 Sat, 15 Oct 2011 12:44:32 EST http://www.compadre.org/informal/items/detail.cfm?ID=11515 http://www.compadre.org/informal/items/detail.cfm?ID=11514 This news article from the National Physical Laboratory describes how physicists updated an experimental test of special and general relativity by flying atomic clocks around the world. The article includes an image of the data, clearly illustrating the result, and also a photo of the traveling clocks. Relativity/Special Relativity/Time Dilation http://www.compadre.org/informal/bulletinboard/Thread.cfm?ID=11514 Fri, 14 Oct 2011 20:56:01 EST http://www.compadre.org/informal/items/detail.cfm?ID=11514 http://www.compadre.org/informal/items/detail.cfm?ID=11510 This article in Physical Review Focus describes how most of the voltage from a lead-acid battery comes from relativistic effects in the lead atom. The article describes the simulation that produces this result, and how the simulation also explains why a tin-acid battery doesn't work. Relativity/Special Relativity http://www.compadre.org/informal/bulletinboard/Thread.cfm?ID=11510 Thu, 13 Oct 2011 12:57:12 EST http://www.compadre.org/informal/items/detail.cfm?ID=11510 http://www.compadre.org/informal/items/detail.cfm?ID=11473 NASA's Earth Observatory "Aircraft Contrails" webpage summarizes the key mechanism, measurements, and predictions of how cirrus clouds produced by contrails contribute to global warming. The page also includes an image showing a large number of contrails produced over the southeastern U. S. Other Sciences/Meteorology http://www.compadre.org/informal/bulletinboard/Thread.cfm?ID=11473 Thu, 15 Sep 2011 16:10:07 EST http://www.compadre.org/informal/items/detail.cfm?ID=11473 http://www.compadre.org/informal/items/detail.cfm?ID=11472 NOVA's The Contrail Effect describes how contrails form and how humidity determines how long they last. The webpage goes on to describe the study during the days of clear skies, without contrails, following 9/11. Three satellite images of contrail patterns are provided. Other Sciences/Meteorology http://www.compadre.org/informal/bulletinboard/Thread.cfm?ID=11472 Thu, 15 Sep 2011 10:17:49 EST http://www.compadre.org/informal/items/detail.cfm?ID=11472 http://www.compadre.org/informal/items/detail.cfm?ID=11460 This NOAA webpage describes contrails and explains both their origins and how they spread out. The page includes a satellite image showing a dense accumulation of contrails over part of Europe. The page also includes a link to a University of Wisconsin webpage with four time-lapse images of contrails spreading over the course of an hour. Other Sciences/Meteorology http://www.compadre.org/informal/bulletinboard/Thread.cfm?ID=11460 Sun, 11 Sep 2011 12:37:15 EST http://www.compadre.org/informal/items/detail.cfm?ID=11460 http://www.compadre.org/informal/items/detail.cfm?ID=11428 This article explains how the Global Positioning System works, including how a GPS receiver determines locations on Earth using satellite information, and how general and special relativity affect the signals transmitted from satellites. The article also links to a NASA video on GPS. Other Sciences/Engineering http://www.compadre.org/informal/bulletinboard/Thread.cfm?ID=11428 Tue, 30 Aug 2011 15:22:37 EST http://www.compadre.org/informal/items/detail.cfm?ID=11428