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Tacoma Narrows Bridge Collapse "Gallopin' Gertie"

Tacoma Narrows Bridge Collapse "Gallopin' Gertie"
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When bridges collapse: Are we underestimating the risk? | Stanford News Old Route 49 bridge crossing over the South Yuba River in Nevada City, Calif. saw local and regional visitors during the atmospheric river event across Northern California on January 9, 2017. (Image credit: Kelly M. Grow/ California Department of Water Resources) Case in point is a bridge along California’s iconic Big Sur coast, which collapsed in March, isolating communities and costing local businesses millions of dollars. “This winter in California has highlighted the vulnerabilities of our nation’s infrastructure,” said Noah Diffenbaugh, a professor of Earth system science at Stanford and the Kimmelman Family Senior Fellow at the Stanford Woods Institute for the Environment. More frequent flooding Big Sur’s damaged Pfeiffer Canyon Bridge – out until at least September – is a harbinger of things to come. A new model In their analysis, the researchers considered the full variability of floods that could cause collapse, as opposed to the 100-year approach taken previously.

Slow motion explosion and shockwave at Green Beret training. Sound Uncovered: An Interactive Book for the iPad Explore the surprising side of sound with Sound Uncovered, an award-winning interactive collection from the Exploratorium featuring auditory illusions, acoustic phenomena, and other things that go bump, beep, boom, and vroom. Hear with your eyes, see with your ears, test your hearing, make and modify recordings—this app puts you at the center of the experiment. Why do some noises seem louder at night? Are there secret messages in music played backward? How can Siri understand different accents? And it's free! Sound Uncovered won the Jackson Hole Science Media Symposium's 2014 Best Online and Interactive Media Award; the American Association of Museum's 2013 Silver MUSE award, Mobile Applications; and Museum and the Web's 2013 Best of the Web Award, Mobile.

Funciones de la música: Kevlar Why do seismic waves travel a curving path through the Earth? Refraction For background on this animation series, download Background from the Resources box.Animations are available for preview in embedded YouTube. To download, right click the 'Quicktime Animation' link and choose 'Save Target As' (PC) or 'Download Linked File' (Mac).Send us feedback. Travel times through different media This animation shows what happens to seismic waves as they encounter a boundary between a slower and faster layer in the Earth with introduction to Snell’s Law. Quicktime Animation (4 MB) Seismic Sprint—race to the seismometer The animation on the left describes the relative speeds of the direct, critically refracted and head waves. Quicktime Animation (1 MB) Seismic Sprint—graphing the seismograms Using the same seismic ray paths, the animation below adds a graph to see how data recorded show the distance transition of first arrival wave paths. Quicktime Animation (3 MB) Direct ray races 5 different refracted rays Quicktime Animation (2 MB) Quicktime Animation (3 MB)

British Council | Reported speech 2 Reported speech (2) Remember that in reported speech we usually change the tense of the direct statement. The present simple tense changes to the past simple, the past simple changes to the past perfect and so on. Here are some other points to consider. ‘Can’ and ‘will’ Direct speech: “I can’t remember his name.” ‘Can’ and ‘can’t’ in direct speech change to ‘could’ and ‘couldn’t’ in reported speech. Direct speech: “I’ll be there for 3 weeks.” ‘Will’ and ‘won’t’ in direct speech change to ‘would’ and ‘wouldn’t’ in reported speech. Other modal verbs Direct speech: “You could be right.” Other modal verbs don’t change in reported speech. Reporting orders, requests and advice Direct speech: “Sit down and shut up!” Orders, request and advice can be reported using an infinitive. Reporting verbs There are a number of verbs that we use to report statements. Direct speech: “It wasn’t me who broke the window.” > He denied breaking the window. There are a number of verbs that can be used to report.

How do P & S waves give evidence for a liquid outer core? Shadow Zones For background on this animation series, download Background from the Resources box.Animations are available for preview in embedded YouTube. To download, right click the 'Quicktime Animation' link and choose 'Save Target As' (PC) or 'Download Linked File' (Mac).Send us feedback. Intro to Shadow Zones The seismic shadows are the effect of seismic waves striking the core-mantle boundary. Quicktime (5.73 MB) Seismic Shadow Zones vs Light Shadows The wave properties of light are used as an analogy to help us understand seismic-wave behavior. Quicktime (9.36 MB) Shadow Zone Rollover Flash interactive rollover shows the different P and S phases and their respective shadow zones. Flash (154 kB) P Phases and the Shadow Zone Animation addresses 5 common variations of P-type seismic body waves. Quicktime (6.31 MB) S Phases and the Shadow Zone Animation addresses 3 common variations of S-type seismic body waves. Quicktime (4.49 MB) Please send feedback to Jenda Johnson.

The Influence of Direct and Indirect Speech on Mental Representations Modeling Earthquake Waves | Earth Science Week An earthquake occurs when massive rock layers slide past each other. This motion makes enormous vibrations, which travel from the site of the earthquake in waves. The waves (seismic waves) travel all the way through the Earth. Seismologists can record these waves when they reach Earth’s surface using seismographs. Earthquakes generate three kinds of waves: Compressional waves (P waves) travel the fastest. Shear (S) waves travel more slowly than P waves. Materials Two Slinkys™Flat, smooth surfaceNotebook and penSafety goggles Procedure Work with a partner.

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