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Introduction to the Physics of Waves - Free eBook Share

Introduction to the Physics of Waves - Free eBook Share | Learning Physics | Scoop.it
eBook Free Download: Introduction to the Physics of Waves | PDF, EPUB | ISBN: 0521197570 | 2012-12-28 | English | PutLocker

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A free textbook, cool stuff!

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Fox eBook's curator insight, July 26, 2013 10:17 PM

Balancing concise mathematical analysis with the real-world examples and practical applications that inspire students, this textbook provides a clear and approachable introduction to the physics of waves. The author shows through a broad approach how wave phenomena can be observed in a variety of physicalsituations and explains how their characteristics are linked to specific physical rules, from Maxwell’s equations to Newton’s laws of motion. Building on the logic and simple physics behind each phenomenon, the book draws on everyday, practical applications of wave phenomena, ranging from electromagnetism to oceanography, helping to engage students and connect core theory with practice. Mathematical derivations are kept brief and textual commentary provides a non-mathematical perspective. Optional sections provide more examples along with higher-level analyses and discussion. This textbook introduces the physics of wave phenomena in a refreshingly approachable way, making it ideal for first- and second-year undergraduate students in the physical sciences.

Table of Contents

1 The essence of wave motion
2 Wave equations and their solution
3 Further wave equations
4 Sinusoidal waveforms
5 Complex wavefunctions
6 Huygens wave propagation
7 Geometrical optics
8 Interference
9 Fraunhofer diffraction
10 Longitudinal waves
11 Continuity conditions
12 Boundary conditions
13 Linearity and superpositions
14 Fourier series and transforms
15 Waves in three dimensions
16 Operators for wave motions
17 Uncertainty and quantum mechanics
18 Waves from moving sources
19 Radiation from moving charges
Appendix: Vector mathematics

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Sticky Tongue: Frogs use non-Newtonian saliva to capture prey

Sticky Tongue: Frogs use non-Newtonian saliva to capture prey | Learning Physics | Scoop.it
Extreme softness makes a frog's tongue a lethal weapon

 

Frogs capture prey using shear-thinning saliva that spreads over insects when the tongue hits and then thickens and sticks when the tongue retracts – according to researchers in the US. In combination with the tongue's unique material properties, this two-phase, viscoelastic fluid makes the tongue extremely sticky, allowing frogs to capture and swallow prey heavier than themselves in the blink of an eye. The research could lead to the development of new types of adhesives and material-handling technologies, say the scientists.

 

Frogs can capture flying insects at astonishing speeds with a flick of their whip-like tongues. But it is not just lightweight insects that they can grab. Research has shown that a frog tongue can pull up to 1.4 times the frog's body weight. And frogs have been recorded capturing larger animals such as mice and birds.

 

At the start of the latest study, Alexis Noel, at the Georgia Institute of Technology in Atlanta, and colleagues, filmed common leopard frogs,Rana pipiens and other species capturing crickets with a high-speed camera at 1400 frames per second. They found that a leopard-frog's tongue can capture an insect in less than 0.07 s – five times faster than humans can blink.

 

The team's calculations show that when the tongue is retracting, the force on the insect can reach 12 times that of gravity. The tongue is able to adhere to prey under such forces because it is extremely soft and viscoelastic, and coated in a non-Newtonian, shear thinning saliva, according to the researchers. Shear thinning is the property of some fluids whereby a shear force on the fluid reduces its viscosity. At low shear rates the saliva is very thick and more viscous than honey. But when subjected to high shear forces, for example when the tongue is accelerating in to prey, the saliva thins, becoming around 50 times less viscous, the researchers found.

 

"During prey impact, the saliva experiences high shear rates, resulting in the saliva becoming thin and liquidy, penetrating insect cracks," explains Noel. "During insect retraction, the saliva experiences low shear rates, firming up and maintaining grip on the insect."


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Metallic hydrogen, once theory, becomes reality

Metallic hydrogen, once theory, becomes reality | Learning Physics | Scoop.it
Nearly a century after it was theorized, Harvard scientists have succeeded in creating the rarest - and potentially one of the most valuable - materials on the planet.

Via THE *OFFICIAL ANDREASCY*
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What potential we have in this!!!!
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Have we reached the end of physics? | Harry Cliff

Why is there something rather than nothing? Why does so much interesting stuff exist in the universe? Particle physicist Harry Cliff works on the Larg
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Gliese 710 is hurtling towards us and could knock millions of asteroids towards Earth

Gliese 710 is hurtling towards us and could knock millions of asteroids towards Earth | Learning Physics | Scoop.it

Researchers have known for a while that a star called Gliese 710 is headed straight for our solar system, but they've now worked out precisely when it should arrive. The star is currently hurtling through space at about 32,000 mph, and is around 64 lightyears away.

 

Gliese 710 is about half the size of our sun, and it is set to reach Earth in 1.35 million years, according to a paper published in the journal Astronomy & Astrophysics in November. And when it arrives, the star could end up a mere 77 light-days away from Earth — one light-day being the equivalent of how far light travels in one day, which is about 26 billion kilometers, the researchers worked out. As far as we know, Gliese 710 isn't set to collide directly with Earth, but it will be passing through the Oort Cloud, a shell of trillions of icy objects at the furthest reaches of our solar system.  

 

"Gliese 710 will trigger an observable cometary shower with a mean density of approximately ten comets per year, lasting for three to 4 million years," wrote the authors of the recent study.

 

Some scientists speculate that a similar event of a star passing through the Oort cloud triggered the asteroid that wiped out the dinosaurs around 65 million years ago. However, the Gliese 710 event could make the dinosaur extinction look relatively minor. At its closest distance, it will be the brightest and fastest observable object in the sky, and as the authors say in the paper, it will be the "strongest disrupting encounter in the future and history of the solar system."

 

But it's also not the only galactic body to worry about. There are as many as 14 other stars that could come within a 3 light-year distance to us any time over the next few million years. 


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Watch What Happens When You Fire A Ball At Sixty MPH Out Of A Truck Traveling Sixty MPH In The Opposite Direction

Watch What Happens When You Fire A Ball At Sixty MPH Out Of A Truck Traveling Sixty MPH In The Opposite Direction | Learning Physics | Scoop.it
In this clip from Mythbusters, the team demonstrates what happens when you fire a ball out of a cannon that is traveling the opposing way, but at the same velocity. If you think about it, it's pretty obvious. But however strong your logic (or even your mathematics and understanding of physics) is, it still doesn’t quite seem right when you see it through a high-speed camera. Next time, we want to see a bullet being fired from a rocket car.   

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Ideas to Review for AP 1 Test

Ideas to Review for AP 1 Test | Learning Physics | Scoop.it
Below are a series of simulated situations used to illustrate major ideas in physics. Next to each link I give you a few things to consider as you explore the environment that was recreated in the program.

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Take a look at these questions, you will see something like this on tomorrows test. Good luck!

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Dolores Gende's curator insight, May 5, 2015 6:22 AM

Series of simulations that illustrate physics concepts. 

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How One Teacher Is Making High School--and Physics--Fun by Gamifying The Classroom

How One Teacher Is Making High School--and Physics--Fun by Gamifying The Classroom | Learning Physics | Scoop.it
Shawn Young turned physics class into a role-playing game, and now he's made the game available to teachers everywhere.

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Prepare to Have Your Mind Blown by a Balloon and a Minivan

Prepare to Have Your Mind Blown by a Balloon and a Minivan | Learning Physics | Scoop.it
If you don't already know why a helium balloon tethered to the floor of a minivan has the power to make your jaw drop, you're going to want to see this. Seriously – set aside five minutes of your time, have a seat and watch. You won't regret it.

Via Dolores Gende
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Really fun!

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Stephen Hawking's black holes 'blunder' stirs debate - CBC.ca

Stephen Hawking's black holes 'blunder' stirs debate - CBC.ca | Learning Physics | Scoop.it
American Live Wire Stephen Hawking's black holes 'blunder' stirs debate CBC.ca The U-turn from Hawking, one of the pioneers of modern black hole theory, surprised his colleagues, said Amanda Peet, a theoretical physicist and associate professor at...
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No Event Horizon!

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Felix Baumgartner's Disorienting and Amazing Fall From Space

Felix Baumgartner's Disorienting and Amazing Fall From Space | Learning Physics | Scoop.it
What it feels like to step out into Earth's atmosphere.

Via Dolores Gende
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I once made a jump of 17 000 feet while serving with the US Army, What Felix did was go 10 time higher!!!!

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How to Make/Build a Van de Graaff Generator

Step-by-step description of making a Van de Graaff generator built using parts from around the house such as a Coke can and rubber bands. -- Too hard for a high school science class?


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Modeling a One Dimensional Collision - Wired Science

Modeling a One Dimensional Collision - Wired Science | Learning Physics | Scoop.it
Can you model elastic and inelastic collisions numerically by using springs? Yes.

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How to keep buildings cool without using electricity or power

How to keep buildings cool without using electricity or power | Learning Physics | Scoop.it

6% of the electricity generated in America is used to power air-conditioning systems that cool homes and offices. As countries such as Brazil, China and India grow richer, they will surely do likewise. Not only is that expensive for customers, it also raises emissions of greenhouse gases in the form both of carbon dioxide from burning power-station fuel and of the hydrofluorocarbons air conditioners use as refrigerants.

 

As they describe in a paper in this week’s Science, Ronggui Yang and Xiaobo Yin of the University of Colorado, in Boulder, have a possible alternative to all this. They have invented a film that can cool buildings without the use of refrigerants and, remarkably, without drawing any power to do so. Better yet, this film can be made using standard roll-to-roll manufacturing methods at a cost of around 50 cents a square meter.

 

The new film works by a process called radiative cooling. This takes advantage of that fact that Earth’s atmosphere allows certain wavelengths of heat-carrying infrared radiation to escape into space unimpeded. Convert unwanted heat into infrared of the correct wavelength, then, and you can dump it into the cosmos with no come back.

 

Dr Yang and Dr Yin are not the first to try to cool buildings in this way. Shanhui Fan and his colleagues at Stanford University, in California, demonstrated a device that used the principle in 2014. Their material, though, consisted of seven alternating layers of hafnium dioxide and silicon dioxide of varying thicknesses, laid onto a wafer made of silicon. This would be difficult and expensive to manufacture in bulk.

 

 Dr Yang’s and Dr Yin’s film, by contrast, was made of polymethylpentene, a commercially available, transparent plastic sold under the brand name TPX. Into this they mixed tiny glass beads. They then drew the result out into sheets about 50 millionths of a metre (microns) thick, and silvered those sheets on one side. When laid out on a roof, the silver side is underneath. Incident sunlight is thus reflected back through the plastic, which stops it heating the building below.

 

Preventing something warming up is not, though, the same as cooling it. The key to doing this is the glass beads. Temperature maintenance is not a static process. All objects both absorb and emit heat all the time, and the emissions are generally in the form of infrared radiation. In the case of the beads, the wavelength of this radiation is determined by their diameter. Handily, those with a diameter of about eight microns emit predominantly at wavelengths which pass straight through the infrared “window” in the atmosphere. Since the source of the heat that turns into this infrared is, in part, the building below, the effect is to cool the building.


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Metallic hydrogen, once theory, becomes reality

Metallic hydrogen, once theory, becomes reality | Learning Physics | Scoop.it
Nearly a century after it was theorized, Harvard scientists have succeeded in creating the rarest - and potentially one of the most valuable - materials on the planet.

 

The material - atomic metallic hydrogen - was created by Thomas D. Cabot Professor of the Natural Sciences Isaac Silvera and post-doctoral fellow Ranga Dias. In addition to helping scientists answer fundamental questions about the nature of matter, the material is theorized to have a wide range of applications, including as a room-temperature superconductor. The creation of the rare material is described in a January 26 2017 paper published in Science.

 

"This is the holy grail of high-pressure physics," Silvera said. "It's the first-ever sample of metallic hydrogen on Earth, so when you're looking at it, you're looking at something that's never existed before."

 

To create it, Silvera and Dias squeezed a tiny hydrogen sample at 495 gigapascal, or more than 71.7 million pounds-per-square inch - greater than the pressure at the center of the Earth. At those extreme pressures, Silvera explained, solid molecular hydrogen -which consists of molecules on the lattice sites of the solid - breaks down, and the tightly bound molecules dissociate to transforms into atomic hydrogen, which is a metal.

 

While the work offers an important new window into understanding the general properties of hydrogen, it also offers tantalizing hints at potentially revolutionary new materials.


Via Dr. Stefan Gruenwald
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All new materials physics!
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Peugeot and Divergent: This Is the World's First 3D-Printed "Supercar"?

Peugeot and Divergent: This Is the World's First 3D-Printed "Supercar"? | Learning Physics | Scoop.it
 

At the Los Angeles Auto Show, automaker Divergent 3D showed off their 3D-printed Blade Supercar. The 635 kilogram (1,400 pound) car is made of a combination of aluminum and carbon fiber; accelerates to 97 kilometers per hour (60 miles per hour) in 2.2 seconds with its 700 hp engine; and can use either gasoline or compressed natural gas as fuel.

 

The Blade Supercar debuted last year in June, heralding the company’s radical, environmentally-sustainable approach to manufacturing. Divergent calls the manufacturing approach NODE, where they 3D print aluminum nodes joined together by carbon fiber tubing.

 

The process, which is similar to using Lego blocks, requires less capital and uses up fewer materials. The ease of assembly means that even semi-skilled workers can run the process.As an added bonus, Divergent 3D’s cars are 90 percent lighter and more durable than cars built with traditional techniques.


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The Physics Video Vault

The Physics Video Vault | Learning Physics | Scoop.it

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Dolores Gende's curator insight, May 9, 2015 7:42 PM

Matt Blackman ‏@UniverseAndMore has collected videos on a variety of units in physics.

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Standing Waves like you've never seen them before [w/video] / Labs, Activities, and Other CoolStuff

Standing Waves like you've never seen them before [w/video] / Labs, Activities, and Other CoolStuff | Learning Physics | Scoop.it
Standing waves are a common phenomenon usually shown through the vibrations of bridges or springs. Horizontal standing waves are produced in a lab by students shaking cords, springs and bungee cords. However, standing waves can also be produced in a vertical fashion by a single student. Using the new nylon Spring Wave, students are able to produce vertical standing waves easily and calculate the speed of the spring. This is a great little "twist" on the age-old standing wave lab that you have in your arsenal.

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Self-propelled subatomic particles accelerate without a push, extending lifetime of unstable isotopes

Self-propelled subatomic particles accelerate without a push, extending lifetime of unstable isotopes | Learning Physics | Scoop.it

Some physical principles have been considered immutable since the time of Isaac Newton: Light always travels in straight lines. No physical object can change its speed unless some outside force acts on it.


Not so fast, says a new generation of physicists: While the underlying physical laws haven’t changed, new ways of “tricking” those laws to permit seemingly impossible actions have begun to appear. For example, work that began in 2007 proved that under special conditions, light could be made to move along a curved trajectory — a finding that is already beginning to find some practical applications.


Now, in a new variation on the methods used to bend light, physicists at MIT and Israel’s Technion have found that subatomic particles can be induced to speed up all by themselves, almost to the speed of light, without the application of any external forces. The same underlying principle could also be used to extend the lifetime of some unstable isotopes, perhaps opening up new avenues of research in basic particle physics.


The findings, based on a theoretical analysis, were published in the journal Nature Physics by MIT postdoc Ido Kaminer and four colleagues at the Technion. The new findings are based on a novel set of solutions for a set of basic quantum-physics principles called the Dirac equations; these describe the relativistic behavior of fundamental particles, such as electrons, in terms of a wave structure. (In quantum mechanics, waves and particles are considered to be two aspects of the same physical phenomena). By manipulating the wave structure, the team found, it should be possible to cause electrons to behave in unusual and counterintuitive ways.


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Roller Coasters

Roller Coasters | Learning Physics | Scoop.it

Many extreme roller coaster these days have vertical loops. Have you noticed that these loops are never circular? Why is this?

They all, also, seem to have the same similar ‘inverted teardrop’ appearance. Why is this?

Clearly there is the same physics and mathematics involved in their designs. Let’s take a look and see if we can derive a formula to describe their shape.

Why are roller coaster loops not circular?


Via Dolores Gende, Gary Faust
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Microscale gravity: Gravitational energy measured with 100,000 times better precision than in previous experiments

Microscale gravity: Gravitational energy measured with 100,000 times better precision than in previous experiments | Learning Physics | Scoop.it
Bouncing neutrons probe dark energy on a table-top, measuring gravity's effects at the quantum scale finds no deviations from Newton's laws.

In this week's Physical Review Letters2, a team led by physicist Hartmut Abele at the Technical University of Vienna shows that the ordinary laws of gravity are still valid even when measured over the scale of a few micrometres. The researchers measured quantized gravitational energy levels with a precision that is 100,000 times better than in previous experiments3.


That precision is sufficient to test some proposed explanations for dark energy — the unknown force that seems to be accelerating the expansion of the Universe. Some models of dark energy put constraints on particular gravity-like forces that would subtly distort the quantum levels at these micrometre scales. “It’s really a beautiful experimental tour de force,” says Geoffrey Greene, a physicist at the University of Tennessee in Knoxville who was not involved in the study.


'Chameleon' dark energy is one such hypothesized force. It derives its name from the way the range over which it acts is reduced drastically for dense objects, which would account for why we fail to see it in Solar System measurements. Such a 'fifth force', existing alongside the known electromagnetic, strong, weak and gravitational forces, would tweak the neutrons' energy levels from those predicted by gravity alone, says Amol Upadhye, a theoretical physicist at Ewha Womans University in Seoul, who was not part of the research team.


The team’s results put a limit on how strong that force could be. “This limit is one hundred times better than the previous such limit,” says Upadhye. This does not eliminate chameleon theories as possible explanations for the dark energy, he adds. “There are still some seven orders of magnitude to cover … but this goes a long way towards closing that gap.”


The results also constrain the properties of a potential candidate for dark matter, the substance thought to make up 85% of matter in the Universe but which seems to be undetectable except for its gravitational pull at cosmic scales. Very light hypothetical particles called axions would cause a deviation from the ordinary law of gravity at short distances. The absence of such an effect in this latest study limits how strong these interactions could be.


"It's truly remarkable that experiments such as this are possible at all," says Upadhye. The researchers call the technique gravity resonance spectroscopy, because it mirrors other kinds of spectroscopy, which measure the energy states of electrons in the electromagnetic field of an atom. These have found a wide range of uses — from determining the composition of faraway galactic objects to atomic clocks. “This first application of the new technology is a big step," says Greene.


Via Dr. Stefan Gruenwald
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9 Apps and Tools for Teaching Physics

9 Apps and Tools for Teaching Physics | Learning Physics | Scoop.it
Physics is one of the most difficult subjects for students to learn and an incredibly difficult one for teachers to find quality apps for use in the classroom.

Via Tom D'Amico (@TDOttawa)
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Robert Dart's curator insight, February 3, 2014 1:01 AM

Some good games here. Will take a while to get through these.

Chia Muhammad Yusuf's curator insight, May 29, 2014 9:58 PM

Useful apps

Heb Morales's curator insight, November 9, 2014 11:20 AM

GRAVITY LAB  LA MEJOR!  

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Vernier Fan Attachment

How to construct and attach a constant force/acceleration fan attachment to a Vernier dynamics cart.

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Free Technology for Teachers: 43+ Alternatives to YouTube

Free Technology for Teachers: 43+ Alternatives to YouTube | Learning Physics | Scoop.it

"Excellent educational content can be found on YouTube. However, not every teacher can access YouTube in his or her classroom. That's why a few years ago I compiled a big list of alternatives to YouTube. Over the years some of those sites have shut-down, started charging a fee, or have switched into another market. So this evening I went through and eliminated some sites from the list and added a few new ones."


Via Beth Dichter, Gary Faust
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Beth Dichter's curator insight, August 13, 2013 10:33 PM

Richard Byrne has updated his list of sites that provide free videos. His top five list is below:

* Next Vista

* PBS Video

* Explore.org

* The National Film Board of Canada

* Vimeo

Each link provides a short description of what the site has to offer. You will also be able to access the fill list of sites through this post.
And if you are trying to search for a video you might want to try out the Custom Search Engine he has created through Google. This search engine is accessible at this link: http://www.freetech4teachers.com/2013/08/a-youtube-free-video-search-engine.html

Videos are a great tool to quickly engage students in learning and this list of websites as well as this search engine are great options to put in your toolbox.

Gary Faust's curator insight, August 14, 2013 2:10 PM

So nice to have an update of video resources. Thanks!

Kimberly House's curator insight, August 15, 2013 4:35 AM

I will certainly be sharing this with staff at my school! The list is thorough and gives a brief desciption of each of the sites mentioned. The list is also up-to-date, having just been checked and edited by it's original creator.

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[1207.0982] Measuring the eccentricity of the Earth orbit with a nail and a piece of plywood

[1207.0982] Measuring the eccentricity of the Earth orbit with a nail and a piece of plywood | Learning Physics | Scoop.it

Also see: http://physicsandphysicists.blogspot.com.au/2012/07/measuring-eccentricity-of-earth-orbit.html

Image from: http://scienceblogs.com/dotphysics/2009/12/28/rp-7-cool-things-the-greeks-di/


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