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  1. blog-0417991001397188086.jpgIn December of 2013 physicists discovered a way to approximate the amplitude of scattering sub-atomic particles in a way that is much, much simpler than the old method. The idea is that given a set of parameters and whatnot, a geometric object, which is being called an amplituhedron, can be constructed such that it's volume equals the amplitude of a scattered particle from a quantum interaction. The old method involved using hundreds to millions of Feynman diagrams, which show possible ways the particle could scatter, and summing the probability of each situation occurring. Even a simple interaction had to be modeled by a formula several billion terms long but the amplituhedron process reduces that to just a few pages of work. For example, the diagram to the left represents an 8 gluon particle interaction. If the same calculation were to be done with the Feynman method it would involve around 500 pages of calculations. The implications of this are enormous, and this may be a big step in the direction of a functional unified field theory.
  2. So, it’s been a few years since I’ve detailed how I make my screencasts, and my workflow and equipment have evolved as I’ve added a few bells and whistles in an attempt to make the screencasts look a touch more professional (and more fun).  Some things have stayed the same, and others, well, not so much.  Here’s the basic workflow.

    The Computer

    27" iMac27″ iMac

    I’m still working on a Mac platform, doing most of my work on a 27-inch 2013-vintage iMac.  I try to keep up to date with the latest version of the operating system, which is currently OS X Sierra.  The iMac includes the higher-end graphics card (NVIDIA GeForce GTX 780M 4096 MB), has an i7 processor, and I’ve installed 32 GB of RAM.  Typically when I purchase a computer I shoot for a five to six year productive life span, at which point I’ll upgrade to a newer model.  This has worked pretty well for me with respect to my Mac laptops (a MacBook Pro), as the last one was in service for about six years, but I’m anticipating this iMac may continue well past that mark.  It still looks beautiful, runs quickly, and with the amount of RAM and the built-in Fusion Drive, its performance doesn’t appear to be in any danger of slowing down in the near future.

    Pen Displays

    Wacom Cintiq 22HDWacom Cintiq 22HD

    Attached to the iMac I have a Wacom Cintiq 22HD pen display unit, which is basically an external monitor that I can “write on” with a special pen, allowing me to annotate the screen as I talk through the video.  I’ve previously used a Wacom DTU-1631, and am looking forward to trying out the newly-released Wacom Cintiq Pro 16 with a USB-C enabled MacBook Pro.  Though the Wacom pen displays are a very significant investment, I’ve been very impressed with their quality and longevity.  The DTU-1631 has lasted five years in the classroom with heavy daily use, and the Cintiq 22HD is just shy of five years of service (though a much lighter workload) and could easily pass for brand new.  These monitors also hold their value extremely well over time.

    Audio & Video

    Blue Yeti MicrophoneBlue Yeti Microphone

    I’ve gotten a ton of mileage out of my Blue Yeti USB microphone… I’ve tried a number of other mics, including lapel mics, and microphones that cost more than three or four Blue Yeti’s, but I haven’t found anything that compares to the quality of the Blue Yeti, especially at its very reasonable price point.  If you want to upgrade your audio from the built-in microphones, this is a very solid choice, and another piece of electronics that has held up well for more than five years of service.

    Canon Vixia HF G20Canon Vixia HF G20

    I’ve put together a small office in my basement to allow for a fairly quick and seamless transition to video creation mode, which includes a foam green screen (and stand).  Especially if you’re just getting started, something as simple as a green flannel blanket can work, though I have to admit, the foam green screen has held up extremely well these past few years (even with the dog sleeping on the portion that sits on the floor at least daily).  They sell rather expensive lighting clips to hold the green screen to the stand, but I found quality clips at a much more reasonable price at the local hardware store.

    Genaray SpectroLEDGenaray SpectroLED

    For illumination, I use a couple of super-cheap reflector work lights coupled with a Utilitech Pro floor LED and a Genaray SpectroLED SP-E-240D mounted on the ceiling.  With a little bit of playing, I can obtain pretty reasonable uniform green screen illumination.  I also use a couple of desktop clip-on lamps to illuminate the foreground (i.e. — my face) in the videos.

    To record my face in the videos, I’m using a Canon Vixia HF G20, saving the digital video file onto an SD card.  Most any digital camcorder or webcam can do the job, however.  While the Canon is recording my face, I’m separately using the iMac and Telestream’s Screenflow 6 (Telestream JUST released Screenflow 7, but I haven’t tried it out yet) to record the Wacom Cintiq screen, as well as recording the input from the Blue Yeti microphone.

    Recording

    Prior to any recording, however, I create my “slides” for the screencasts using Apple’s Keynote software, and export those slides as a PDF.  I then open the PDF using Zengobi’s Curio software, which is the software actively running on the Wacom screen that I use to annotate the slides.  If you haven’t tried it out, Curio is a pretty amazing piece of software that allows you to do so much more than just write on PDF slides…  if you have a Mac, it’s worth checking out for a variety of purposes!

    So, the workflow.  With everything set up, I have Screenflow 6 start recording the Wacom screen while recording the Blue Yeti mic, and simultaneously I start up the Canon video camera.  Once I’ve gone through the lesson, I stop Screenflow from recording and stop the Canon video camera.  I should now have an SD card that contains the digital video file of my face (with sound recorded from the Canon’s rather poor microphone), and a Screenflow 6 file that has video from the Wacom screen coupled with the Blue Yeti-recorded sound.

    Now it’s time to put the video all together.  First I export the digital video file from Screenflow 6, taking care to export at 29.97 fps and not 30 fps so that it will match up to the Canon digital video file.  Then, using Final Cut Pro on the Mac (coupled with the Motion and Compressor add-ons), I create a project and import both the recorded screen video file and the video camera file.  Using Final Cut, I create a combined clip from these two files and have Final Cut Pro sync them up based on the audio (although the sound from the Canon camera is poor, it’s good enough to sync the clips together).  Next, I mute the sound from the Canon camera, so that I now have my recorded screen video below my “live action” video, but using only the sound from the recorded video screen, which was recorded with the Blue Yeti mic.

    Editing

    Chroma Key EffectChroma Key Effect

    Next it’s time to edit.  First step is to take care of the green screen effect (formally known as chroma key), which Final Cut Pro does quite easily.  I remove the green color from the “live action” file using the “Keyer” effect, and tweak it as needed to get the desired result.  I then shrink the clip down and position it where I want, so that I have the live video taking up just a small portion of the screen, the background green from the video shows as transparent, and what shows through from underneath is the recorded video from the Wacom screen.

    The hard part’s done.  Final steps now involve fixing any audio issues, clip editing if necessary, adding any titles, and appending on the opening and closing video sequences, which were created using Adobe Premiere Pro, After Effects, and Audition from Adobe Creative Cloud.  Once I have the video looking the way I want in Final Cut Pro, I use Compressor to export it in multiple formats — high definition video for YouTube, and an APlusPhysics-specific size and quality for viewing directly from the APlusPhysics site.

    Next Steps

    Moving forward, I would really like to spend some time working with my old iPad to see if I can re-purpose it for use as a teleprompter.  I tend to spend a lot of time up front planning my videos, but still have yet to come up with a slick, efficient way of presenting notes to myself while I’m making a video.  I have to believe there’s a reasonable way to have my notes show up on my iPad and use some sort of remote (perhaps my phone?) to scroll through PDF notes on my iPad as necessary.  Currently I tend to tape my paper notes to the bottom of the camera, which is chock-full of problems, messiness, and opportunity for improvement.

    Back to Reality

    If it sounds like there’s quite a bit of work involved, you’re not wrong, but don’t think you have to go to anywhere near this level of complexity or expense to make quality screencasts.  My workflow has evolved over the years as I’ve tinkered and gone through a length set of try/fail sequences to learn what works for me and provides the level of quality I’m after.  Much of what I do can be accomplished in a similar manner using fairly basic tools — Techsmith’s Camtasia software coupled with a Webcam, a USB lapel mic, and most any digitizing tablet will get you pretty solid results without a huge investment.

    Even though this article is a technical how-to / what do I use, I’d still like to end with two bits of advice I’ve learned from doing things the hard way more times than I can count.

    • First, and foremost, a flipped classroom is NOT about the videos, it is about building more in-class time for active learning strategies such as hands-on activities, group problem solving, deep-dives into a topic, discussions, etc.  The videos themselves are such a tiny part of the whole equation, and are primarily a means to create more available class time.
    • Second, though it can be fun to doctor-up your videos and add all sorts of bells and whistles, realize that these embellishments and investments of time and resources have extremely minimal payback in the form of student learning and performance.  If you’re interested in doing these things, make sure you’re doing them because you want to and think it’s going to be fun, but don’t expect to see any sort of substantial learning improvement with higher quality videos (which brings me back to item one… it’s not about the videos!)

    Useful References

    The post Creating Screencasts (Mac) – 2017 Update #edtech #flipclass appeared first on Physics In Flux.

    LQzT412Hips

  3. In working through the Magnetism unit, one really good question came to surface; Is it possible to have a magnet with only one pole? What would it mean to have a monopole after all?

    Monopoles are essentially a theoretical particle, an isolated magnet with only one magnetic pole. This would mean that the particle would have a net magnetic charge. What would that mean in simple terms? The notion that the magnetic field has zero divergence would be proven wrong; in fact, magnetic particles would most likely behave even more similarly to electric particles, in that not only would magnetic particles have two opposing charges, but, in the same manner negatively and positively charged particles exist, north and south pole magnetic particles would also exist; the "south pole magnets" and "north pole magnets" would not have to cancel out, a rule already accepted in physics today.

    What do you guys think? What would the discovery of a monopole (if one exists) mean for what we already understand about electromagnetism?

  4. Did I just get hit with a dump truck or did I just take the AP Physics C exams? Turns out, I took the exams.

    Yes, they're over....and with a massive sigh of relief, I can move on with my life and enjoy the rest of my senior year.

    But I must be honest...they were the hardest exams I have ever laid my eyes on, and it came as a wake up call to me that, yes, maybe I DO have to work harder in future physics courses.

    This year in physics, although rough academically, taught me that one cannot simply understand a concept with ease at this level (with a few exceptions...)

    So as I move on with life, I will take physics at RIT at least knowning what to expect, and I'll have a working knowledge of the basics.

    But seriously, those exams hit me like a truck. And the truck had spikes and chainsaws in the front. Yes, it was pretty violent.

  5. Walking is something that we do every day, without thinking about it. Its seems very simple and straight forward. You just put one foot in front of the other and you move. But it is kind of complicated. It has a lot to do with forces. Newton's laws of motion are involved. So what do forces have to do with walking?

    Newton's third law states that every action has an equal and opposite reaction. This is relevant to walking because when you put your foot on the ground, you are applying a force to it. In doing this, the ground also actually applies an equal force onto your foot, in the opposite direction, pushing you forward.

    efthimiou-fig.5.jpg

    When running, you tend to take longer strides because you are applying a larger force to the ground, so the ground must apply a larger force onto your body. When a larger force is applied to your foot, you go farther, taking a longer step.

    Another law of motion that is at work is Newton's first law of motion. An object in motion stays moving, and an object at rests stays at rest unless an outside force acts on it. If people didn't apply forces to the ground, they obviously wouldn't move. This is because the ground then doesn't apply a force to the persons foot. They would stay at rest. But also, if it weren't for gravity, we would all float up into space the second we took one step. This is because the ground applies a force onto us, so we are set into motion. Gravity keeps this force from pushing us all the way into space.

    (there is also centrifugal force that wants to fly people off of the planet, but ehh.)

    funny-cat-on-fan-o.gif

  6. gdaunton
    Latest Entry

    blog-0282305001410276478.jpgWhat's this? New AP-C students?

    Welp a new dawn has... dawned and I have made the short stroll of 18 miles to RIT. So what has changed? Not much.

    Right now you AP-C'ers are taking, I assume, mostly college level courses and believe it or not they are actual college level classes, like no joke. With Calculus, Physics and other classes I was (and you are) taking the equivalent of a Freshman year in college. If it sounds intimidating its because it is, taking that big of a step a year early is very tough and will, at points, seem like the worst decision of your life.

    Don't get me wrong senior year is lots of fun, but remember, if a class like Calc or Physics is getting you down, hold on. At some point or another you will have to realize that not all knowledge is easy to learn and high school is the best place for that. Mr. Fullerton is amazing and he, unlike a college professor, will help you through every step if he needs to.

    Enjoy yourself and

    make it a great year!

    Oh yeah, READ THE TEXTBOOK (I have to pay for mine, use it while it's free)

    Have fun and stay classy,

    Shwiby

  7. blog-0178454001370757516.jpgThe Quantum Physics of Alice and Wonderland

    Lewis Carroll had some interesting ideas in his works, especially in Alice in Wonderland. Alice falls asleep in a meadow, dreams of plunging through a rabbit hole, then finds herself too large and then too small. She meets new and bizarre characters on her way as well, including the Cheshire Cat, the Mad Hatter, the March Hare, and the King and Queen of Hearts. She experiences wondrous, often strange adventures, trying to reason in numerous discussions that do not follow the usual paths of logic. Finally she totally rejects the dream world and wakes up. This book almost mirrors the theories of quantum physics. Things in extremes: things too small and too large. Just like the tiniest particles you can think of--quarks and electrons--and the biggest thing you can think of-- galaxies, black holes, and more recently discovered, the Large Quasar Group.

    blogentry-546-0-76859900-1370806031_thum

    http://www.livescience.com/23232-smallest-ingredients-universe-physics.html

    http://www.huffingtonpost.co.uk/2013/01/14/quasar-cluster-largest-object-einstein_n_2470562.html

    Quantum disobeys many theories in classical physics. Especially many of Newtons claims, and now even Einstein's. It reveals laws which could have the slightest bit of chaos to change entire equations already used in classical physics and logic. Alice does crazy things that would not have normally been seen as proper or normal. She gets really big, then small, falls into rabbit holes, talks to cats... And, everything in physics is about a cat as we all know, and the Cheshire Cat explains to Alice that everyone in Wonderland is mad, including Alice herself, hence it must be right. The Cheshire Cat gives directions to the March Hare's house and fades away to nothing but a floating grin. Cats can do everything. They can be alive, be dead, be alive and dead (vampire cats), not in a box, in a box, or floating in mid air with only its teeth showing.

    blogentry-546-0-30015500-1370757456_thum

    Many things in Alice in Wonderland are illogical or just confusing and weird, this is all you need to know about quantum physics. The mallets and balls in a game of croquet (in this wonderland) are live flamingos and hedgehogs. And there are illogical laws much like in quantum physics with the Queen frantically calling for the other player's executions. Amidst this madness, Alice bumps into the Cheshire Cat again, who asks her how she is doing. Obviously some cats worry. But the King of Hearts interrupts their conversation and attempts to bully the Cheshire Cat, who impudently dismisses the King. The King takes offense and arranges for the Cheshire Cat's execution, but since the Cheshire Cat is now only a head floating in midair, no one can agree on how to behead it. In the Schrodinger's cat, there is a cat enclosed in a chamber with a vial containing hydrocyanic acid, a radioactive substance. If even a single atom of the substance decays during the test period, a relay mechanism will trip a hammer, which will, in turn, break the vial and kill the cat. The Copenhagen interpretation of quantum mechanics implies that after a while, the cat is simultaneously dead and alive. (This is all in theory.) So similarly, in this case, no one can decide whether the cat is both dead and alive, or either dead or alive in this wonderland, no one can decide how to behead the cat.

    blogentry-546-0-35200300-1370757478_thum

    Alice's wonderland is much like the theories and laws of quantum physics. There could be the most structured laws in physics, but the tiniest bit of randomness occur in quantum physics which causes much stress, chaos, and a lot of calculus for scientists and science itself. Such complex theories and complex and imaginary numbers make this wonderland of physics. I can understand how Carroll, being a man of mathematics, could make such a book. Mathematics is so literal and straightforward, and makes you a little mad. Some theories make you wonder whether we are existing at all, and whether time is real. Math can make you crazy just by trying to explain how 1 is larger than 0, or how to describe a straight line in 20 pages.

    blogentry-546-0-74562900-1370757431_thum

    Alice in Wonderland is a book which has underlying tones of reality and debate over many theories of quantum physics. This does not surprise me because Carroll was a rather exceptional student of Oxford, where he studied mathematics and was great at Aristotelian logic. The author's life and work has become a constant area for speculation and his exploring of the boundaries of sense and nonsense which has inspired a number of psychological studies and novels.

    They are against Alice's common sense: 'I can't believe that!' said Alice. '... one can't believe impossible things. But the White Queen has her own principles: "Why, sometimes I've believed as many as six impossible things before breakfast.' (from Through the Looking Glass) Which is possible...and impossible! Everything, anything and nothing may and may not occur in quantum physics, but above all, only some of it is in theory, the rest is true, and there is proof and evidence backing it all up. As for Alice in Wonderland, that�s up for you to decide.

    http://www.npr.org/2010/11/12/131274183/the-spookiness-of-quantum-mechanics

  8. username
    Latest Entry

    blog-0539677001397240367.pngThe physics of tornadoes is very interesting. It all has to do with pressure and angular momentum. When air is heated it expands causing the density to decrease. This decrease in density combined with the higher density air around it causes the heated pocket to rise. The surrounding air then rushes in to fill the void and a tornado is born. The tornado is perpetuated by its own angular momentum.

    To learn more check out http://outreach.phas.ubc.ca/phas420/p420_04/sean/

  9. blog-0186348001397180170.jpgIn physics we assume that gravity is a constant. In fact we represent this constant with the letter g and the numerical value of 9.81m/s2. Almost everything we learned this year works on the assumption that gravity is constant on the surface of the earth. There is no reason to assume other-wise after all we don't just see objects floating randomly as we take a stroll down the street. We use physics and its assumption of constant gravity- on the earth's surface- to create a lot of our technology today. But what if gravity on the surface of the earth wasn't constant? Many of our technologies would be rendered useless while other would become very amusing. So here are some fun things to think about if we all woke up one day and gravity was no longer constant.

    When your alarm clock beeps in the morning waking you up for school there are many fates you may encounter. If the gravity was lower then 9.81m/s2 then you might not wake up in your bed at all. Instead you could be floating in your sleep. Just think about how much room you could save without the need for a bed! If gravity however was at a larger magnitude then 9.81m/s2 then you would be pulled down to the surface of the earth with greater force. If the force was great enough it could leave you immobile. Hey, I guess that means you don't have to go to school!

    Let go to the next phase of the day. Unfortunately, most mornings I have to walk to the school in the mornings. However with a smaller magnitude of gravity I could take less steps! Although similar to walking on the moon this process would take a lot longer. If gravity all of a sudden gravity shifted to a greater magnitude, even just lifting my foot off the ground would take tremendous effort.

    For those of you dieting I have both good news and bad news. A world in which gravity is always shifting means your weight is always shifting. Take note that its your weight and not your mass which shifts. Mass is a measure of the space you take up- how many particles. Weight is the measure of mass multiplied by gravity. If you were to stand in a spot of low gravity then you lost weight! however, take one step to the right and you've gained more weight in a single second then ever thought possible!

    Last scenario. You're in class at school and your teacher tells you to pass up your homework. In a situation with gravity of an extremely low magnitude you could argue, "I tried to do my homework last night but it kept pushing me away." In a situation with no gravity newton's 3rd law has a field day. This law states for ever action there is a opposite and equal reaction. As you try to touch you homework, your homework pushes back at you with an equal reaction. Due to the extremely low gravity the reaction might actually cause you be pushed away. Then gravity shifts to a grater magnitude and your teacher tells you to do your homework. In this scenario you simply complain, "The force of gravity was so strong that the force I exerted on my pen was not great enough. In this process of trying to create a force stronger then the force of gravity it seems I have sprained my wrist.... both of my wrists."

  10. blog-0533966001397176772.pngI attend the local Rochester parkour gym (http://www.rochesterparkour.com/) on a weekly basis. I also tend to struggle to come up with topics for my physics blog posts. But today, I had a revelation: why not combine the two. So I introduce my new series, the physics of parkour. First up is the "top-out".

    A top-out is essentially a way to go from a hanging position on a ledge (a "cat"), to having your upper body above the ledge with your palms supporting you, without clambering up with your elbow in between. Here's a mock up of it:

    blogentry-1313-0-69968800-1397175837_thu

    And a video (if you only want to watch the top-out, and not all the instruction, you can go to 5:12):

    It relies on three things: a solid footing, a good knee drive with the hanging leg, and of course maintaining a solid grip with your arms. When done properly, it requires a lot less upper body strength then you might imagine.

    For a brief overview, it consists of three parts: building upwards momentum with your legs, building a bit of forward (but mainly rotational) momentum with your arms (the reason why they play more into rotation more than anything will be discussed), and finally transitioning to the support position resting above your palms. First, and most important, is the legs. One is planted firmly, and the other is supposed to drive upwards, in order to build momentum which will later be transferred to the rest of your body. However, friction can be tricky: the tendency of your planted leg is to slip and slip, because most people will "paw" at the wall as if they were running up it. As we know, frictional force is proportional to normal force, so you actually want to kick/jab your foot into the wall, because this will allow it to stay in place. As you're doing this, you can drive your hanging leg up, generating some momentum.

    During this, you should also be pulling up/in with your hands. Simply, you want to counteract/overcome the force of your leg pushing away from the ledge, and also gather a bit more upwards momentum. However, simply due to the weaker nature of our arms, it won't contribute quite as much as our legs, which can be surprising. What is helpful, though, is the torque it creates on the body: while it is counteracting the linear momentum from our legs, it is working with the force from our legs to rotate our body over the lip, which is more beneficially, seeing as we right next to the wall to begin with. Now, with momentum built up from our knee drive and arms, and a slight rotation, our upper body will pop up and over the ledge, and rotate us into a position where we can easily re-position our hands to rest on our palms.

    From there, it is usually pretty easy to swing/climb up the rest of the way. But without proper training, this technique is very difficult, because people usually rely on their arms way too much. Yet again, it's an example of something made easier through physics.

  11. Honestly, this whole E & M section of Physics C has not been going so great for me. We're supposed to have our last unit test on electromagnetism tomorrow, but I took it today because I won't be here tomorrow. We finish it the Monday after break, and it's safe to say I left about 75% of that test blank because I didn't know the answers.

    I think I struggle with concepts more than anything. I just can't visualize the problem like I could in mechanics, so none of the processes we go through to get answers seem logical to me.

    Anyway, I need to work on memorizing formulas too. I know induced current is big and necessary, but unfortunately today I forgot that equation during the test. I also need to study capacitors and inductors and how they act in circuits, as well as how to use all those equations with e in them in the RL/LC circuits .

    I think a huge contributor to my misunderstanding is how I watch the videos. I watch them and take notes, but don't always comprehend what the point(s) of the video was/were, and then I go a couple days without looking at my notes on them and I forget almost everything.

    As you can see, I have my work cut out for me over break. I know this isn't a typical blog post, but I also know that I am running out of ideas, and this helped me work out my issues which is good.

    Until next time,

    bazinga818

  12. blog-0336975001371137334.jpgIn many of our video games and even in real life we sometimes come into contact with a hunting rifle or sniper rifle. For some games its just point and shoot and you hit him but for some games and in real life you have to compensate for the drop of the bullet. But did you also know that, that bullet you just shot and the case of that bullet as it flies out are hitting the ground at the same time? But back to the drop of the bullet when you fire. When you fire really any gun you have to aim a bit up from your target depending on the distance you are at. Gravity pulls the bullet down even if it might seem that it would take awhile as the bullet comes out of the gun gravity is acting on it and the bullet is being dragged down but slower that other objects because of the speed it is at. So next time you go hunting and you think that you are going to get the animal right in the sweet spot try aiming a little higher then where you want it to go, then it might be right on.

    But to come back to something, the drop of the bullet and the shell of the bullet. These two things drop and hit the ground at the same time. As you shoot the bullet goes flying off at high speeds, but when you pull the bolt back on the rifle and the case flies out and hits the ground, both parts of the bullet have hit the ground. They are technically experiencing the same thing its just the bullet shot is experiencing it over a greater distance with a greater speed.

  13. Everyone knows that one of their favorite past times is sitting in front of the television and watching movies, shows, or playing video games. However with this almost motionless, lazy activity comes a great deal of static physics and mechanics.

    When you are sitting down enjoying whatever show it is you may be watching, you actually have several forces acting on you concurrently. For example, by sitting on the couch with no extra weight on you, your weight is equivalent to the normal force, or the force of the couch on you. In addition to the force of the couch of you, if you are leaning on an arm or laying down, a similar force acts on you, except at an angle or incline. The general rule for laying on the couch watching television is that whatever force you exert on an object, that object exerts the same force in the opposite direction, or 180 degrees around.

    Next time you sit down and watch some television, remember that you are under the rules of static physics!

  14. After taking this class we now can all answer the question that stumped us at the beginning of the year; What is physics? its everything. The crazy part to think is that its actually true. Anything anyone could ever think of has to do with physics. Tomorrow we take our final for this class, struggling to remember every little thing we can. The crazy part is that taking that test is physics.

    If we're lucky, we'll drive to the test. How does a car run? and electric circuit. physics. Along the way you probably have to pick up a friend or two, and you use your cell phone to tell them you have arrived. Another electric circuit. Hopefully before all of this you showered, and thanks to gravity the water fell down on you instead of floating. After that you stumble around your room trying to find clothes that match thanks to all the colors we are able to see on the spectrum.

    Arriving at the school, you have to have an acceleration from sitting in your car to get into the testing room. Although some will be moving at an incredibly slow constant pace, trying to avoid the test. Sitting in your test you will put a force on the chair, which will then push up on you at the same force to keep you in that chair. Thanks to the florescent lights we will be able to see our test.

    So while you're studying, don't say you don't know much about physics! Because everything you do, even going to the test is physics!

    Best of luck!

    that-physics-test-we-took-today-created-by-aliens.jpg

  15. This year was a good year in physics. I learned a lot about a bunch of different subjects. One of my favorite subjects was kinematics because it applies to a lot of different things. Throughout these blogs posts I used a lot of different kinematic references. My personal favorite was the drifting post because not only is drifting awesome, it can apply to so many different things in physics.

    images?q=tbn:ANd9GcSfxQjY1LogJ7wwWN1Er-dRRqFaZVNzVwyTFD3KWYYwti0q3ABhCw

    The year has been really good though. I really enjoyed all of the labs we did because they were fun and they applied to everything we learned. Good luck to all of next years physics students.

  16. In early September, in the very beginning of my time in AP Physics C, I was hesitant about the workload and difficulty of the course. When Mr. Fullerton introduced integrals to us for the first time, I knew from then on that the class would be no piece of cake. The funny thing looking back is that I enjoyed the calculus parts of physics by the end of the year very much. With a solid calculus background, the "hard math" aspect of the AP did not seem so hard. For me, the hardest part of the class was reading the problems and deciding in which direction to think. I had trouble reading the questions and immediately knowing which equation to use first, which equation to use second, and so on. I tried helping myself by reading the textbook and taking notes, along with making flashcards for the equations. By the time the AP rolled around, I was nervous, but felt prepared to do well. After taking the AP, I am happy to say that Mr. Fullerton prepared us very well as he made our tests harder than the AP itself. All in all, I look forward to the physics I take in college. I hope that from the AP tests I get some college credit; but if I do not, I know that I will at least have the background necessary to succeed in physics mechanics and electricity/magnetism. I wish the best to all of my AP Physics C classmates and the future students of AP Physics C! Go Physics!

  17. blog-0380869001397237126.pngIt's been quite a while since I've seen a Star Wars movie, but I still remember the necessities from all the movies. It doesn't take a physics prodigy to understand that there are many physically-impossible aspects of the series, but its good to use the imagination every once in a while and ignore these impracticalities. Nonetheless, I can use my knowledge of physics thus far to analyze certain parts of the series. First of all, when the tie-fighters and x-wings explode in the movies, they make a tremendous amount of noise. However, knowing that sound cannot travel through a vacuum (in space) we know that the explosions would be silent. George Lucas, being a smart man, probably already knew this, but nobody wants to watch space ships silently explode. Furthermore, the concept of hyperspace is introduced in the fourth film. Through breakthrough special effects, the audience is encouraged to believe that the characters travel enormous distances in matter of seconds. Knowing that the speed of light, the fastest thing in the universe, (more so than the Millennium Falcon), is only 3.00 x 10^8 m/s, it seems highly unlikely that the characters could transport so fast.
  18. It's everybody's favorite physics problem: the elevator! One does not learn mechanics without encountering the elevator problem (as far as I know). This is an interesting, sort of different take on it though.

    http://www.cbs.com/shows/scorpion/video/46616DDC-D143-4956-909B-9B31759797B6/scorpion-i-love-machines/

    I'll be honest, the first I saw this I had no idea why Walter and Toby were tying their belts to the elevator bars. But it all makes sense about 5 seconds later when a rather...well....happy Happy stopped the elevator very suddenly. The belts looped around their arms and the elevator bars keep the duo from a painful collision with the ceiling of the elevator, a fate their captors cannot avoid. By why do they slam into the top of the elevator when its acceleration is downward, why don't they hit the ground instead?

    Let's start with what we know about elevators.

    elev.gif

    So this is pretty nifty! We are looking at the "accelerating downward" one. What we know is that while the elevator accelerates downward, the net force on the person is actually upward. This occurs due to the support force of the cable holding the total weight of the person and the elevator. We know from this that the net force (F=ma) on the person is total support force minus the force of gravity on the system. Therefore the net force on the person is less than their actual weight (thus the idea of weighing less in a downward accelerating elevator). What does this have to do with our problem from the episode? Well, we know from looking at this that person doesn't actually float (as much as I'd like that to happen) when the elevator moves down, but the contact force between the person and the floor of the elevator has lessened since the normal/net force on the person is less. Now we bring in the idea of inertia. The human body, in this case will want to stay at rest with in the elevator, so we are not seeing the people accelerate upward but rather the their bodies attempting to stay in place the elevator floor "falls out" from under them (so to speak). Their bodies will attempt to remain still as the elevator moves downward in short bursts and thus they are thrown into the ceiling. Well, Walter and Toby aren't, they have their belts. Although, I do wonder how they did not break an arm or something.

    Anyways, that's all I've got to say, so thanks for reading!

  19. Hello once again audience! Today I'm going to talk about a duo of absolutely awesome government assassins from The Avengers, Black Widow and Hawkeye (also known as Natasha Romanov and Clint Barton). Now you might be thinking, what's so super about these two people? They are just people, no super powers or anything. Well I can tell you that they are in fact super with their accuracy.

    Let's start with Hawkeye. Like his name says, his eyes are like a hawk's. But how precise is that?

    Precise enough to shoot a flying alien space craft without even looking! Hawkeye's power is this excellent accuracy with his bow and arrow.

    Next we'll move on to Black Widow. At first she seems like any other pretty girl. Wrong!

    She learned super self defense techniques with, like Hawkeye, excellent accuracy.

    Now, many superheroes seem completely unrealistic and could never be alive in real life. But Black Widow and Hawkeye are like real people. The government and other people have assassins just like the S.H.I.E.L.D. agents in Avengers. The CIA, FBI, SWAT, you name it. These super characters aren't as fictional as they seem. Lil' Bretz singing off.

  20. DavidStack
    Latest Entry

    Well this is kind of bittersweet, finally being done with blog posts but also realizing that high school is completely over, as is Physics C with a fantastic teacher. I've learned so much during the year, from angular analogs to retarding forces to induction to the sheer brilliance of Walter Lewin's ability to draw a dotted line; it's been quite a year. I've appreciated this blog posts as much as I've hated them, mostly because they forced me to truly learn the stuff that I write about. And now when I struggle with physics in college, I'll always be able to go back to APlusPhysics and ask for help. I encourage anyone and everyone to take Physics C - it's certainly challenging but I can't see how you could regret it. So, farewell APlusPhysics, I'll likely come crawling back in no time at all.

  21. blog-0695092001370015461.jpgAs many of us know Iron Man 3 has made its debet earlier this month and has many new and exciting aspects of physics in it. One scene in the movie is of Tony Stark's house being blown up by helicopters. The really exciting part isn't the house bursting into flames, but when Tony is being dragged down to the ocean floor by debre from the house. This got me thinking, would Tony and the Iron Man suit sink on its own or stay afloat?

    In order to stay afloat or have neutral bouyancy, the suit would have to have a density of at least 1 because that is the desity of water. If the desity of an object is exactly 1 it will be neutral in bouyancy. This means that the object will not sink nor float unless acted on by an outside force. With a density of more than 1 the object will sink. The greater the density the more eager the object will be to sink to the bottom. The same goes for densities less than 1.

    Being made of different types of alloys and metal the Iron Man suit will most deffinetly have a desity of more than one. So on its own with Tony in it, he would sink to the bottom....

    However this could be overcome with ballast tanks. By regulating the amount of water in these tanks the density of the object with the tanks changes. This is how submarines submerge and return back to the top. Knowing the limitless boundries of Tony Stark the capabilities of Iron Man could very well include submersion.

  22. Soooo, because this is my last blog post for this year ( :o), I thought it would be fitting to do a course reflection on the AP-C physics class this year. I thought I'd do it in a "bests-vs-worsts" top 5 format, kind of like you could find on collegeprowler.com when viewing different schools.

    Top 5 Bests:

    5.) Blog Posting [i thought this was really fun! I've never done anything like this before for a class. It brought up interesting physics applications and I thought it was fun to converse with classmates on the site :) ]

    4.) Independent Units [As uncomfortable as I was at first, independent units forced me to manage my time, work harder than usual to learn the topic, and was great preparation for college. I feel like everyone sould experience this kind of a unit before graduating]

    3.) Assigned practice problems from the readings [Assigned problems were REALLY helpful. I would've struggled a lot more than I did had I skipped doing the sample problems]

    2.) Units with Lecture & book follow-up [This is my favorite way to learn things! The read-then-lecture method]

    1.) VIDEOS <3 [Hands down the most helpful resource in Physics]

    Top 5 Worsts:

    ...I think this is my biggest beef. I really don't have 5 things to complain about.

    1.) Readings weren't assigned [When life gets busy in the middle of the year, especially with a number of APs, sports, etc., readings are the first thing to get cut out for me if they're not assigned. Confession: when the going got tough, I would often skim or not read. I reccomend assigning readings in the future. Kids will complain, but they'll thank you when they see better grades and their AP score.]

    Overall, this was a successful year. A note to future students: This is by far the hardest AP course I've taken throughout high school. If you want to succeed, you must:

    A.) Read the textbook and do some practice problems

    B.) WATCH THE VIDEOS. Whether you're confused or simply want review, these are soooo outrageously helpful. It's like being in class a second time, except in 15 minutes or less instead of 42. Plus, you can skip over any sections that you feel you know solid.

    C.) REVIEW THE EQUATIONS AND FREE RESPONSE BEFORE THE AP. I went through most of the E&M free response questions as well as both E&M and mechanics equations before the exam. KNOW THE EQUATIONS! I swear equations and key concepts are the majority of the test when it comes to the multiple choice Qs.

    Any favorite parts of the year? Things you wanted to change? Post below with your opinion!

    ...I can't believe we only have 1 more day of physics :(

  23. Light is subject to a quantum theory called wave-particle duality. This theory proposes that matter exhibits both properties of a particle and properties of a wave.

    The experiment that shows light's wave-like properties is the double slit experiment. when light was shone through two slits close together, and a screen was placed behind the slits, the impact pattern didn't look the way one would expect a particle impact pattern to look like. After going though the slits, the light diffracted, creating a wave diffraction pattern on the screen, showing light's wave-like properties.

    Light's particle properties are shown in another experiment. Light is passed through "absorber" planes, which don't affect waves. however, when the light passed through the absorbers, the wave after going through the absorber was considerably weaker. This confirmed that light has some particle like properties.

    Light is neither particle nor wave and yet exhibits properties of both, which can be experimentally observed.

  24. blog-0947931001370821242.jpgThis is completely random, but as I was pondering ideas for a blog I discovered that there is a lot of physics involved in toasters! :thumbsu:

    Most appliances that heat up, such as hair dryers, irons, and toasters, work by changing electrical energy into heat energy. Toasters are plugged into a source of electricity. From that source, the electric current runs down the wire and into the toaster. The inside of each appliance contains loops of different metals. The electricity does not easily flow through the metals. The metals slow down the electrons and hold up the current, which is resistance. Resistance is a measure of the tendency of a material to resist the flow of an electrical current, in physics. The higher the resistance, the hotter the metal will get. This happens because of the friction of the electrons.

    The wires begin to heat up and glow because they are so hot. This heat is what toasts the bread.

    Overall this is very random, but its cool to see how everyday appliances like toasters relates to physics!

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