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Physics education on the move

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New Book Release: Honors Physics Essentials

[ATTACH=CONFIG]308[/ATTACH]Honors Physics Essentials is an easy-to-read guide to algebra-based introductory physics, featuring more than 500 worked-out problems with full solutions and covering topics such as: kinematics, dynamics, momentum, impulse, gravity, uniform circular motion, rotational kinematics, work, energy, power, electrostatics, circuits, magnetism, microelectronics, waves, sound, optics, thermal physics, fluids, and modern physics. This book is designed to assist beginning physics students in their high school and introductory college physics courses as an invaluable supplemental resource in class as well as a review guide for standardized physics assessments such as the SAT Subject Test in Physics, PRAXIS Physics, and CST Physics exams. Honors Physics Essentials is integrated with the APlusPhysics.com website, which includes online question and answer forums, videos, animations, and supplemental problems to help you master high school physics. Check it out at http://www.aplusphysics.com/honors.

FizziksGuy

FizziksGuy

 

National Novel Writing Month!

Guess what... November 1st starts the annual month-long NaNoWriMo (National Novel Writing Month) extravaganza. Amateur and professional writers across the world will struggle to write 50,000 words during the month, with the support and assistance of thousands of others from the NaNoWriMo.org website. The reason? One month to write 50,000 words is a challenge, and that challenge will keep you moving forward in your writing, saving edits and redrafts for later. Join us and see what you can do! http://youtu.be/miBhmLA62O4 www.NaNoWriMo.org

FizziksGuy

FizziksGuy

 

Physics of Angry Birds

Saw a comment from Frank Noschese (Action-Reaction) not long ago mentioning how cool it would be to make an Angry Birds physics motivational poster... took a couple days of fiddling with fonts and effects to get the text right, but I think I finally got a winner! [ATTACH=CONFIG]150[/ATTACH] For more information, check out: Dot.Physics: The Physics of Angry Birds and Action-Reaction: Angry Birds in the Physics Classroom.

FizziksGuy

FizziksGuy

 

Regents Physics SBG Objectives 2011-2012

I've been hammering out our Skills-Based Grading (SBG) objectives for Regents Physics for the coming school year, pulling from the tremendous efforts already in place and utilized by folks such as Frank Noschese, Kelly O’Shea, and others, as well as our state and district standards. In defining these, we were conflicted about how detailed and specific to make our goals, providing students more concrete feedback on their objectives, compared to more general objectives that allow for more interpretation and generalization of the “big picture” concepts. Eventually, we settled on a fairly specific list of concrete objectives in an effort to provide students specific information on what they need to do well on the end-of-year state culminating exam. These are absolute minimum baseline standards, provided with the strong understanding that these baseline objectives will be augmented throughout the year as we teach significantly above and beyond the state minimums. For example, our current list of magnetism objectives is quite limited, and will most certainly grow in individual classrooms as all our physics classes spend significantly more time on electromagnetic induction than is required to meet the state minimums. With this large number of objectives, assessment and feedback could become quite involved, which is where our implementation of Gravic Remark OMR will be of tremendous benefit in streamlining assessment on a specific type of standardized exam. Of course, we’ll still have our hands full with more authentic assessments, student-initiated assessments, labs, activities, etc., but it’s a start, and of course, we can always adjust as the year progresses. Here’s our first pass rough draft: Math Review MAT.A1 I understand and can estimate basic SI units
MAT.A2 I can convert basic SI units using common metric prefixes
MAT.A3 I can convert compound SI units
MAT.B1 I know the difference between scalar and vector quantities
MAT.B2 I can use scaled diagrams to represent and manipulate vector quantities
MAT.B3 I can determine x- and y-components of two-dimensional vectors
MAT.B4 I can determine the angle of a vector given its components
MAT.C1 I can draw accurate graphs and solve for the slope and y-intercept
MAT.C2 I can recognize linear and direct relationships and interpret the slope of a curve
MAT.C3 I can recognize quadratic and inverse relationships
MAT.D1 I can solve algebraic equations symbolically and numerically
MAT.D2 I can utilize the Pythagorean Theorem to solve problems involving right triangles
MAT.D3 I can utilize basic trigonometric identities to solve for sides and angles of right triangles
MAT.E1 I can use my calculator to solve algebraic equations with exponents
MAT.E2 I can use scientific notation and significant figures effectively
General Skills GEN.A1 I can design a reliable experiment that tests a hypothesis, investigates a phenomenon, or solves a problem
GEN.A2 I can communicate the details of an experiment clearly and completely with a formal lab report
GEN.A3 I can record, analyze, and represent data in a meaningful way
GEN.A4 I can identify sources of uncertainty and error
GEN.B1 I can solve problems using the FSA format
GEN.C1 I can properly utilize a metric ruler, meter stick, protractor, mass balance and stopwatch
GEN.D1 I can use writing to clearly and constructively communicate my thoughts to others using proper grammar, spelling, organization, and punctuation
GEN.D2 I can use technology effectively and appropriately to further my learning
GEN.D3 I can engage in constructive and responsible discourse in both small and large group environments
Constant Velocity Motion VEL.A1 I know the difference between position, distance and displacement
VEL.A2 I can calculate both distance and displacement
VEL.B1 I know the difference between average speed and velocity, and instantaneous speed and velocity
VEL.B2 I can solve problems involving average speed and velocity, and instantaneous speed and velocity
VEL.C1 I can interpret/draw motion diagrams for objects moving at constant velocity
VEL.C2 I can interpret/draw d-t and v-t graphs for objects moving at constant velocity
Constant Acceleration Motion ACC.A1 I can define acceleration and I know the difference between acceleration and velocity
ACC.A2 I can calculate acceleration with both direction and proper units
ACC.B1 I can interpret/draw motion diagrams for objects moving with changing velocity
ACC.B2 I can interpret/draw d-t, v-t, and a-t graphs for objects moving with changing velocity
ACC.C1 I can use kinematic equations to solve problems involving objects with changing velocity
ACC.C2 I can use kinematic equations to solve problems involving objects in free fall
ACC.D1 I understand that the vertical and horizontal motions of a projectile are independent of one another
ACC.D2 I can solve problems involving projectile motion for projectiles fired horizontally
ACC.D3 I can solve problems involving projectile motion for projectiles fired at an angle
Dynamics DYN.A1 I understand Newton’s 1st Law of Motion and can define mass and inertia
DYN.B1 I know the relationship between acceleration, force, and mass (N2)
DYN.B2 I can draw a properly labeled free body diagram showing all forces acting on an object
DYN.B3 I understand the relationship between the weight and mass of an object.
DYN.B4 I can determine unknown forces, accelerations, etc.
DYN.C1 I understand the meaning of Newton’s 3rd Law of Motion
DYN.C2 I can recognize and identify force pairs
DYN.D1 I can define and identify frictional forces
DYN.D2 I know the factors that determine the amount of static/kinetic friction between two surfaces
DYN.D3 I can determine the frictional force and coefficient of friction between two surfaces
DYN.E1 I can calculate the parallel and perpendicular components of an object’s weight to solve ramp problems
UCM & Gravity UCM.A1 I can explain and calculate the acceleration of an object moving in a circle at a constant speed
UCM.A2 I can define centripetal force and recognize that it is provided by forces such as tension, gravity, and friction
UCM.A3 I can solve problems involving calculation of centripetal force
UCM.A4 I can calculate the speed, period, frequency, and distance traveled for an object moving in a circle at constant speed
UCM.B1 I can state and apply Newton’s Law of Universal Gravitation
UCM.B2 I know how mass and separation distance affects the strength of the gravitational force between two objects
Momentum and Impulse MOM.A1 I can define and calculate the momentum of an object
MOM.A2 I can determine the impulse given to an object
MOM.A3 I can use impulse to solve a variety of problems
MOM.A4 I can interpret and use F vs t graphs
MOM.B1 I can apply conservation of momentum using momentum tables to solve a variety of problems
MOM.C1 I can distinguish between elastic and inelastic collisions
Work, Energy, and Power WEP.A1 I can define and calculate the work done by a force
WEP.A2 I can calculate the kinetic energy of a moving object
WEP.A3 I can calculate the gravitational potential energy of an object
WEP.B1 I can solve problems using the law of conservation of energy
WEP.B2 I can solve problems using the work-energy theorem
WEP.C1 I can calculate the power of a system
WEP.D1 I can utilize Hooke’s Law to determine the elastic force on an object
WEP.D2 I can calculate a system’s elastic potential energy
Electrostatics ELE.A1 I understand and can calculate the charge on an object
ELE.A2 I can describe the differences between conductors and insulators
ELE.A3 I can explain the difference between conduction and induction
ELE.A4 I understand how an electroscope works
ELE.A5 I can use the law of conservation of charge to solve problems
ELE.B1 I can use Coulomb’s Law to solve problems related to electrical force
ELE.B2 I can compare and contrast Newton’s Law of Universal Gravitation with Coulomb’s Law
ELE.C1 I can define, measure, and calculate an electric field
ELE.C2 I can solve problems related to charge, electric field, and forces
ELE.D1 I can define and calculate electric potential energy
ELE.D2 I can define and calculate electric potential difference (voltage)
ELE.D3 I can solve basic parallel-plate capacitor problems
Circuits CIR.A1 I can define and calculate an electric current
CIR.A2 I can define and calculate resistance using Ohm’s Law
CIR.A3 I can explain the factors and calculate the resistance of a conductor
CIR.B1 I can identify the path and direction of current flow in a circuit
CIR.B2 I can draw and interpret schematic diagrams of circuits
CIR.B3 I can use voltmeters and ammeters effectively
CIR.C1 I can calculate the equivalent resistance for resistors in series
CIR.C2 I can solve series circuits problems using VIRP tables
CIR.D1 I can calculate the equivalent resistance for resistors in parallel
CIR.D2 I can solve parallel circuit problems using VIRP tables
CIR.E1 I can define power in electric circuits
CIR.E2 I can calculate power and energy used in circuits
Magnetism MAG.A1 I understand that magnetism is caused by moving charges
MAG.A2 I can describe the magnetic poles and interactions between magnets
MAG.A3 I can draw magnetic field lines for a magnet
MAG.B1 I can describe the factors affecting an induced potential difference due to magnetic fields lines interacting with moving charges
Waves WAV.A1 I can define a pulse and a wave
WAV.A2 I understand the difference between a mechanical and an EM wave
WAV.A3 I understand the difference between a longitudinal and transverse wave
WAV.A4 I understand the relationship between wave characteristics such as frequency, period, amplitude, wavelength, and velocity
WAV.B1 I can utilize the superposition principle to analyze constructive and destructive wave interference
WAV.B2 I understand and can predict the result of the Doppler Effect
WAV.B3 I can recognize standing waves and explain nodes, antinodes, and resonance
WAV.C1 I can apply the law of reflection to plane surfaces
WAV.C2 I can explain the cause and result of refraction of waves
WAV.C3 I can utilize Snell’s Law to solve problems involving wave refraction
WAV.D1 I understand the principle of diffraction and can identify its effects qualitatively
WAV.E1 I recognize characteristics of EM waves and can determine the type of EM wave based on its characteristics
Modern Physics MOD.A1 I can explain the wave-particle duality of light
MOD.A2 I can calculate the energy of a photon from its wave characteristics
MOD.A3 I can calculate the energy of an absorbed or emitted photon from an energy level diagram
MOD.A4 I can explain the quantum nature of atomic energy levels
MOD.A5 I can explain the Rutherford and Bohr models of the atom
MOD.B1 I can explain the universal conservation laws (mass-energy, charge, momentum)
MOD.B2 I recognize the fundamental source of all energy in the universe is the conversion of mass into energy
MOD.B3 I understand the mass-energy equivalence equation (E=mc^2)
MOD.C1 I can explain how the nucleus is a conglomeration of quarks which combine to form protons and neutrons
MOD.C2 I understand that each elementary particle has a corresponding anti-particle
MOD.C3 I can use the Standard Model diagrams to answer basic particle physics questions
MOD.D1 I can define the known fundamental forces in the universe and can rank them in order of relative strength

FizziksGuy

FizziksGuy

 

13 Highest Paying College Degrees

The Huffington Post recently published an article on the 13 best-paying college majors. Note that 12 of the 13 require a strong physics and science background, and all 13 require strong math skills. Thanks to Louis Carusone of Eastridge High School for sharing this article and link. You can find the entire article online at the Huffington Post. I have summarized their data below: [TABLE="align: left"] [TR] [TD]Major[/TD] [TD]Median Starting Pay[/TD] [TD]Mid-Career Median Pay[/TD] [/TR] [TR] [TD]Petroleum Engineering[/TD] [TD]$97,900[/TD] [TD]$155,000[/TD] [/TR] [TR] [TD]Chemical Engineering[/TD] [TD]$64,500[/TD] [TD]$109,000[/TD] [/TR] [TR] [TD]Electrical Engineering[/TD] [TD]$61,300[/TD] [TD]$103,000[/TD] [/TR] [TR] [TD]Materials Science / Eng[/TD] [TD]$60,400[/TD] [TD]$103,000[/TD] [/TR] [TR] [TD]Aerospace Engineering[/TD] [TD]$60,700[/TD] [TD]$102,000[/TD] [/TR] [TR] [TD]Computer Engineering[/TD] [TD]$61,800[/TD] [TD]$101,000[/TD] [/TR] [TR] [TD]Physics[/TD] [TD]$49,800[/TD] [TD]$101,000[/TD] [/TR] [TR] [TD]Applied Mathematics[/TD] [TD]$52,600[/TD] [TD]$98,600[/TD] [/TR] [TR] [TD]Computer Science[/TD] [TD]$56,600[/TD] [TD]$97,900[/TD] [/TR] [TR] [TD]Nuclear Engineering[/TD] [TD]$65,100[/TD] [TD]$97,800[/TD] [/TR] [TR] [TD]Biomedical Engineering[/TD] [TD]$53,800[/TD] [TD]$97,800[/TD] [/TR] [TR] [TD]Economics[/TD] [TD]$47,300[/TD] [TD]$94,700[/TD] [/TR] [TR] [TD]Mechanical Engineering[/TD] [TD]$58,400[/TD] [TD]$94,500[/TD] [/TR] [/TABLE]

FizziksGuy

FizziksGuy

 

Book Review: The 32 Most Effective SAT Math Strategies

[ATTACH=CONFIG]149[/ATTACH]Steve Warner’s 32 Most Effective SAT Math Strategies is more than a book of secrets to help students maximize their SAT math scores… it’s also a guide to problem solving and learning strategies that extend considerably beyond the bounds of the SAT exam itself. As a physics teacher, I can strongly assert that the most effective review book for any test is the book the student will use, and that requires a friendly, concise text that is clear, easy-to-read, and well paced. Warner’s book does this and more, coaching students to maximize their results while minimizing effort. Outside the context of SAT exam preparation, the strategies detailed in The 32 Most Effective SAT Math Strategies provide a pathway to grow the reader’s general problem solving skills. Readers are encouraged to solve problems, learn independently, and attempt higher level challenges, enhancing their mathematical and logical maturity levels as they attempt to not only solve, but understand, the given problems. I highly recommend this book for anyone preparing for the SAT exam, as well as those looking to refresh their basic mathematical skills and enhance their ability to think logically. And make sure to check out his website, which has free problem sets, tips, and videos!

FizziksGuy

FizziksGuy

 

10 Quick Tips to Maximize your Regents Physics Scores!

Although by no means an exhaustive list, these 10 quick tips may help you secure that extra point or two on your upcoming Regents Physics exam. Mass and inertia are the same thing.
To find the resultant, line your vectors up tip-to-tail, and draw a line from the starting point of the first vector to the ending point of the last vector.
Any object moving in a circular path is accelerating toward the center of the circle.
Acceleration of an object is equal to the net force on the object divided by the object’s mass.
The normal force always points at an angle of 90° from the surface.
Opposite charges and magnetic poles attract, likes repel.
Gravitational forces and electrostatic forces both follow an inverse square law relationship, where the strength of the force is related to one divided by the square of the distance between the charges/masses.
The force of gravity on an object, commonly referred to as weight, is equal to mg, where g is the gravitational field strength (also referred to as the acceleration due to gravity).
The mass-energy equivalence can be calculated using E=mc^2. If a mass is given in universal mass units, however, you can do a straight unit conversion using 1u = 931 MeV.
Protons and neutrons fall into the category of baryons, which are hadrons. Smaller particles, such as electrons, fall into the category of leptons. Mesons are rare, weird particles you probably haven’t heard of.
Most importantly, use your reference table. When in doubt, write down the information you're asked to find, what you're given, and use your reference table to help you narrow down what you should be doing. In the free response part of the test, make sure to show your work in detail with a formula, substitution with units, and an answer with units. Find these and many more tips for success at APlusPhysics.com.

FizziksGuy

FizziksGuy

 

Upcoming Regents Exam... Get Your Review Books

[ATTACH=CONFIG]144[/ATTACH]For those anticipating the upcoming Regents Physics exam on June 15th, APlusPhysics: Your Guide to Regents Physics Essentials is a book designed to give you everything you need to score well on the exam in a simple, easy-to-read manner. Filled with sample problems and full solutions, the book is now only $10.07 from Amazon!

FizziksGuy

FizziksGuy

 

Book Review: Just Enough Physics

[ATTACH=CONFIG]142[/ATTACH]Prof. Allain has taken his Dot.Physics introductory blog posts and formed them into a fun and entertaining e-book covering the basic principles of mechanics. From his initial advice not to use the e-book as a table leg prop to his discussion of differential equations in chapter 15, Just Enough Physics provides students a light, simple, and concise explanation of algebra-based physics. Further, Just Enough Physics actually includes directions on basic VPython programming for simple physics simulations… if you’re like me and have been reticent to dive into simulation and programming, this text provides several code snippets with clear explanations that entice you to see what you can do by way of numerical simulation and computer modeling. As a high physics teacher and engineering professor, I highly recommend this book for beginning physics students of any age.

FizziksGuy

FizziksGuy

 

APlusPhysics: Regents Physics Essentials review book Now Available!

[ATTACH=CONFIG]125[/ATTACH]The first APlusPhysics course guide book, APlusPhysics: Your Guide to Regents Physics Essentials, by Dan Fullerton (aka FizziksGuy) is now available for direct order, and will be available in early May from major book retailers such as Amazon.com and Barnes and Noble. From the book's description: APlusPhysics: Your Guide to Regents Physics Essentials by Dan Fullerton is a clear and concise roadmap to the entire New York State Regents Physics curriculum, preparing students for success in their high school physics class as well as review for high marks on the Regents Physics Exam. Topics covered include pre-requisite math and trigonometry; kinematics; forces; Newton's Laws of Motion, circular motion and gravity; impulse and momentum; work, energy, and power; electrostatics; electric circuits; magnetism; waves; optics; and modern physics. Featuring more than four hundred questions with worked out solutions and detailed illustrations, this book is integrated with the APlusPhysics.com website, which includes online question and answer forums, videos, animations, and supplemental problems to help you master Regents Physics essentials. Advance Praise for APlusPhysics Regents Physics Essentials: "Very well written... simple, clear engaging and accessible. You hit a grand slam with this review book." -- Anthony, NY Regents Physics Teacher. "Does a great job giving students what they need to know. The value provided is amazing." -- Tom, NY Regents Physics Teacher. "This was tremendous preparation for my physics test. I love the detailed problem solutions." -- Jenny, NY Regents Physics Student. "Regents Physics Essentials has all the information you could ever need and is much easier to understand than many other textbooks... it is an excellent review tool and is truly written for students." -- Cat, NY Regents Physics Student

FizziksGuy

FizziksGuy

 

APlusPhysics Regents Course Tutorials Completed!

Whew! It’s been a long and challenging project, but I am thrilled to announce that the APlusPhysics.com Regents Physics course tutorial has been completed (well, at least the first revision). I’ve been done with the tutorial less than 20 minutes, and already I’m making notes on additions, modifications, and enhancements, but I think it’s worth taking a moment to step back and look at everything that’s been accomplished. [ATTACH=CONFIG]96[/ATTACH] A year ago I had never created a web page, and didn’t know the difference between HTML and ELMO. But, with a vision to create a resource specific to the needs of the students I see every day, and with the support of friends and family, I started picking up books, reading web articles, and making many, many designs on paper to script out what I wanted to build. As of this morning, with the upload of a question bank of more than 500 Regents Physics questions from past years, I’m amazed at how much has been created. The APlusPhysics Regents Tutorials include objectives, explanations, sample problems, FLASH animations, integrated quizzes, videos… just about everything you could ask for in an online resource tailored to a specific course. Further, as the projected progressed, I began to see potential for this resource being used outside my classroom and even outside the scope of NY’s Regents curriculum, and have begun building in further topics of interest to many introductory physics students. Even better, I learned the Regents Physics material better than I could have ever imagined (there’s nothing like digging through 10 years of old exams to help you really learn a course inside and out). I wanted this website to be an original work, so not only did I learn webpage design, I also had to learn vector and bitmap graphics, flash animation, basic flash programming, and even a little bit of PHP to make everything work in the background. For an artistically-challenged science guy, I’m pretty amazed with the quality of illustrations I was able to create after reading a few books on the modern tools available! In support of the static web tutorials, the site also features a discussion forum based on the latest version of vBulletin, integrated student and educator blogs, course notes, calendars, project activities, and even hosting for old episodes of the Physics in Action Podcast. So what’s next? I’ve said from the beginning I want to follow up the Regents Physics tutorials with the AP-1 and AP-2 curricula, but with delays from the College Board, we’re all still waiting to find out exactly what those courses will entail (and to what depth). I have been considering creating a tutorial for AP-C physics, but I’m not certain I see as great a need for such a site, as the AP-C course mirrors many introductory university physics courses, and that material is already widely available throughout the web. With these challenges in mind, I think I’m on hold for creating static tutorial pages for the time being. This feels like a blessing in disguise, however, as I’ve been quite excited to dive into several other projects. First, I want to expand the build out the Semiconductor Technology Enrichment Program (STEP), a program designed to take the weeks in class after the AP Physics exams and introduce students to basic semiconductor physics and micro/nano technology. Second, I need to spend time planning on the details of the Skills Based Grading (SBG) program I’m planning on implementing in my Regents Physics courses next year. Third, I’d like to continue my work to pre-record video lessons of all the major topics in the Regents Physics course, with the ultimate goal of spending in-class time working on hands-on lab activities, as well as supporting students individually and in small groups, and minimizing the less-effective entire-class-instruction time. Finally, several students have inquired as to whether I might take the course content material on APlusPhysics and expand it into a written mini-book / synopsis for the Regents Physics course. Though initially hesitant, the more I think about it, the more I find value in creation of the written “APlusPhysics’s Guide to Regents Physics.” And oh, by the way, did I mention the list of website enhancements I’ve already started on? The question, then, is where to start. I oftentimes prioritize items both by “bang for the buck” as well as cost to implement. SBG work will largely occur in late spring and early summer due to some outside interests and external timing constraints. The STEP program may find some external funding in a month or so, and if I can get paid to work on something, why not wait until there’s a bit of income for my time? That really leaves the printed physics guidebook, video mini-lessons, and website revisions. As much as I try to deny it, I know I’ll be working on website revisions by tonight, in tandem with my next project. So which to tackle next, the video mini-lessons, or the printed guidebook? Or both? Would love to hear your feedback and thoughts! And, as with any endeavor of such scale, allow me to again thank all my supporters, colleagues, family members and contributors. This is a huge milestone for APlusPhysics and the culmination of hundreds of hours of frustration and effort, which has already paid for itself in learning and confidence. I’ve come out all the better for it, and I hope this resource helps others say the same.

FizziksGuy

FizziksGuy

 

Vacuum may have friction after all!

From New Scientist Magazine A BALL spinning in a vacuum should never slow down, since no outside forces are acting on it. At least that's what Newton would have said. But what if the vacuum itself creates a type of friction that puts the brakes on spinning objects? The effect, which might soon be detectable, could act on interstellar dust grains. In quantum mechanics, the uncertainty principle says we can never be sure that an apparent vacuum is truly empty. Instead, space is fizzing with photons that are constantly popping into and out of existence before they can be measured directly. Even though they appear only fleetingly, these "virtual" photons exert the same electromagnetic forces on the objects they encounter as normal photons do. Now, Alejandro Manjavacas and F. Javier García de Abajo of the Institute of Optics at the Spanish National Research Council in Madrid say these forces should slow down spinning objects. Just as a head-on collision packs a bigger punch than a tap between two cars one behind the other, a virtual photon hitting an object in the direction opposite to its spin collides with greater force than if it hits in the same direction. So over time, a spinning object will gradually slow down, even if equal numbers of virtual photons bombard it from all sides. The rotational energy it loses is then emitted as real, detectable photons (Physical Review A, DOI: 10.1103/PhysRevA.82.063827). The strength of the effect depends on the object's make-up and size. Objects whose electronic properties prevent them from easily absorbing electromagnetic waves, such as gold, may decelerate little or not at all. But small, low-density particles, which have less rotational momentum, slow down dramatically. The rate of deceleration also depends on temperature, since the hotter it is the more virtual photons pop in and out of existence, producing the friction. At room temperature, a 100-nanometre-wide grain of graphite, the kind that is abundant in interstellar dust, would take about 10 years to slow to about one-third of its initial speed. At 700 °C, an average temperature for hot areas of the universe, that same speed decrease would take only 90 days. In the cold of interstellar space, it would take 2.7 million years. Could this effect be tested in the lab? Manjavacas says the experiment would require an ultra-high vacuum and high-precision lasers to trap the nanoparticles, conditions that are "demanding but reachable in the foreseeable future". John Pendry of Imperial College in London calls the analysis a "fine piece of work" and says it could provide insights into whether quantum information is ever destroyed, for example, when it falls into a black hole. He says the real photons emitted during the deceleration process should contain information about the quantum state of the spinning particle, much as the photons thought to escape from black holes as Hawking radiation are thought to encode information about the holes. "This is one of the few elementary processes that converts what appears to be purely classical mechanical energy into a highly correlated quantum state," Pendry says. Read full article here...

FizziksGuy

FizziksGuy

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