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FizziksGuy

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Blog Entries posted by FizziksGuy

  4. FizziksGuy
    [ATTACH=CONFIG]68[/ATTACH]
    A colleague and friend of mine has offered a $20 Starbucks gift card to the student who can provide the simplest, clearest explanation of why the angular velocity and angular acceleration vectors point in the directions they do... check out the details and submit your entries in our Forums section!

    http://bit.ly/guQV0L


  5. FizziksGuy

    Unrolling Toilet Paper

    By FizziksGuy,

    In his Dec. 17 Action-Reaction blog post titled "Falling Rolls," one of my heroes of physics instruction, Frank Noschese, details an exercise from Robert Ehrlich's book Why Toast Lands Jelly-Side Down.

    The exercise, a rotational motion problem that challenges students to find the ratio of heights at which you can drop two identical toilet paper rolls, one dropped regularly, the other dropped by holding onto the end of the paper and letting it unroll, such that the two rolls hit the ground at the same time. It's a terrific, easy-to-replicate and demonstrate problem that pulls together a great number of rotational motion skills --> finding the moment of inertia, applying the parallel-axis theorem, identifying forces and torques from free body diagrams, and converting angular acceleration to linear acceleration. My students dove into the challenge with zest!

    To begin the exercise, we set our variables (H=height for dropped roll, h=height for unrolled roll, r = inner diameter, R = outer diameter), then identified the time it takes for the dropped roll to hit the ground using standard kinematics:



    Next, we did the same thing for the unrolling toilet paper roll:



    Of course, if we want them to hit at the same time, the times must be equal, therefore we can show:



    Obviously, what we really need to focus our efforts on is finding the linear acceleration of the unrolling roll. To save ourselves some time, we started by looking up the moment of inertia for a cylinder:



    Using the parallel-axis theorem to account for the unrolled roll rotating about its outer radius we find:



    Next, we can use a free body diagram to identify the net torque on the roll as MgR, and use Newton's 2nd Law for Rotational Motion to find the angular acceleration:



    Since linear acceleration can be found from angular acceleration multiplied by the radius of rotation ®:



    Finally, since we're looking for the ratio of the dropped height to the unrolled height:



    This conflicts with the results from Noschese's class, where they derived

    However, their demonstration based on their results is very convincing. Let's take a look at the difference in ratios using the two derivations:

    For a toilet paper roll of inner diameter .0095m and outer diameter R=.035m (our school rolls from the janitor supply closet):





    It appears that our derivation is correct, per our visual confirmation with a high speed video camera:




    You can follow the original blog response at Physics In Flux.
  6. FizziksGuy
    Over the river and through the words, to grandmother's house we go...
    the horse knows the way to carry the sleigh through the white and drifting snow - oh!

    [ATTACH=CONFIG]67[/ATTACH]
    As part of our family's holiday season festivities, we went on a horse-drawn sleigh ride through the woods in northwest Pennsylvania. It was a terrific time, with low winds, just a very light dusting of now coming down, and 28 degree temperatures.


    As Miss Micro-APlusPhysics (aged 16 months) drove the sleigh, I couldn't help but think what a terrific multi-faceted physics problem our trip would make... finding the force of friction the horses had to overcome to keep us moving at a constant velocity through the woods, the power supplied, and the energy consumed.




    Of course, being a physics teacher, I couldn't just leave it there:


    With nine people on the sleigh, all bundled up, I think we can estimate an average mass of about 70 kg per person (we had a couple lightweights, including the baby.) So, the mass on the sleigh was probably on the order of 650kg. The sleigh itself was made out of fairly solid boards with steel runners, and a quick attempt at lifting up a corner provided a feel for its weight -- let's estimate the sleigh at 550kg, giving us a total load of 1200kg. The weight of the load, then, settles in a 12,000N.


    The horses pulled the sleigh from a horizontal tether, so that given the equilibrium condition of the sleigh, we know the normal force had to offset the weight, so the normal force of the snow on the sleigh is 12,000N. Now, to estimate the coefficient of friction. From the NY Physics Regents Reference Table, we find the coefficient of kinetic friction for a waxed ski on snow as 0.05. This seems like a reasonable esimate for the frozen runner on the snow. Using we find the force of friction as 600N.


    For most of the 20-minute (1200s) journey the horses pulled us at a leisurely constant speed of approximately 1.5 m/s. Therefore, we can assume the applied force of the two LARGE Belgian horses as 600N. The power supplied can be calculated from P=Fv, or (600N)*(1.5 m/s) = 900W. And since they applied that power for roughly 1200s, the work done by the horses can be found from W=P*t=(900W)(1200s)=1,080,000 Joules, or the equivalent of 258 food calories (roughly the nutritional equivalent of one slice of pizza)!


    A fun holiday activity providing another opportunity to highlight physics in the world around us.
  7. FizziksGuy
    If you're interested in publicizing your blogs outside just the APlusPhysics community, and perhaps put yourself up for a Blog of the Year award in 2011, consider listing your blog at Edublogs. You can click here to submit your blog for inclusion in their directory of educational blogs. You can find your RSS feed by clicking on the small orange RSS button on the top right of your blog!
  9. FizziksGuy
    A colleague and respected writer from the physics blogosphere asked me this morning if I could explain what APlusPhysics is all about, and why it's worth the effort. Wanting to build up the APlusPhysics community, of course I jumped on the opportunity to distribute information about the project, especially to someone who has a significant following on her blog -- we can use all the targeted advertising we can get!

    I had many convoluted answers to the request, but realized I hadn't truly put them together into a "big picture" view of my vision and goals for the site. So, with the help of several friends who graciously offered their critical thinking and editing skills, I believe I have a reasonably complete answer to her question. My response, which I also posted on my personal A+ Physics blog, may be of general interest to readers here, so I'm including it below:



    My goal with APlusPhysics is to create a friendly, coherent and dynamic online resource with a consistent theme; an integrated toolset which can be easily customized to meet the needs of a diverse student and educator constituency while incorporating best known practices in physics education research. The site is designed for easy integration with physics modeling strategies, standards based grading (SBG), mastery learning, and “alternate pathway” programs which support students who, for various reasons, aren’t able to fit into the standard classroom educational model.

    It’s a work in progress. I’m learning as I go, refining, expanding, deleting and rebuilding. And then doing it all over again. I’m thankful for the support of the physics community as they provide feedback, ideas, opportunities, and constructive criticism that allow for continual refinement and growth from a variety of perspectives, and whose thoughts and ideas are the foundation of this online conglomeration. I hope you find APlusPhysics a useful web resource, and this blog an insightful journal of a developing teacher’s successes, failures, challenges, struggles, and achievements.

    Welcome one and all!

    WHO AM I?
    I’m a high school physics teacher learning something new every day. I was an engineer in industry for more than 10 years, and an adjunct college professor for eight, yet after three years teaching standard introductory (Regents) as well as AP-B and AP-C physics classes, it is obvious to me that student learning styles are changing rapidly… the standard “by-the-book” pedagogy is no longer the optimal method for teaching all students. I need to find a way to differentiate across a wide range of abilities, interests, backgrounds and habits if I want to help each of my students grow to their maximum potential in the brief time I have with them.

    I don’t have all (or many of) the answers — I don’t even have all the questions! What I do have is the energy and ability to learn, make changes, take risks, succeed, fail, and ultimately, grow. This blog details my journey.

    WHY GO TO THE TROUBLE?

    Writing is thinking. Writing forces you to organize your thoughts, to make mental connections — analyzing what’s worked, and what hasn’t. It forces you to think through your next steps, to reflect on why your experiments succeed and fail. It helps to recognize what you do and don’t know, providing a well-lighted path toward “filling in the gaps.”

    No single text or resource completely matches the way you teach. Our class text is a wonderful resource for our students, and I was even lucky enough to serve on the committee which selected the book during my second year in the classroom. It’s accurate and thorough. It aligns nicely to our district outcomes and state standards. But it’s not designed specifically to the course I teach and the method in which I teach it.

    Further, students are reluctant to learn and read independently from our text. This is troubling. The most important skill I can teach my students before they leave my classroom and go on to bigger and better things is the ability to teach themselves. Empowering them as learners requires technical reading, critical thinking, and discipline. I struggle with this throughout the entire year, and each year set a goal to extend my students’ independent learning skills through guided inquiry, discovery, and practice. Still, though, in many cases, even with our text, there are gaps.

    BRIDGING THE GAPS

    I have embarked on a project to create my own online physics resource, tailored specifically to course objectives, with as little extraneous information as possible, and consistent with the methods and organization I use in my classroom. I’m learning and changing every day, so this resource has to be dynamic. Problem solving practice with immediate and constructive feedback should be integrated into every unit. Most importantly, students should learn at their own pace. With a tremendous span of abilities, backgrounds, and learning styles, it’s obvious that one size and speed doesn’t fit all.

    Key aspects of this resource, APlusPhysics, include online discussion forums promoting discourse about concepts, applications, and new developments in science; online homework help where students can assist each other (the best way to learn is to teach!); student and educator blogs for learning logs and self reflection; course content distilled down to the “need-to-know” facts with a variety of sample problems, designed specifically to meet course objectives; built-in quizzes to allow students to test their understanding; and resources for physics instructors focusing on student-centered active learning activities.

    Many of these resources can be found, in whole or in part, elsewhere on the web. The Physics Classroom is a terrific online resource covering a wide variety of topics in physics; Cramster is a terrific resource for homework help and problem solving; Physics Forums is a terrific bulletin board system discussing physics developments and problems; Castle Learning offers students a tremendous repository for problem solving practice; and of course there are many others.

    I’m not trying to rebuild or re-create any of these terrific resources… they all have tremendous potential for the students who take the time to learn and use them productively. However, the learning curve for this expanse of resources can seem insurmountable to the new physics student already exhibiting the classic “deer-in-headlights” shock I’m sure all physics teachers are familiar with. This project is an ongoing method of delivering, refining, and reflecting upon high school physics education.
  10. FizziksGuy
    Scientists have been measuring the universal gravitational constant, G, for hundreds of years. But, how accurate are they in their measurements? Is G truly a constant? It’s a question physicists and astronomers continue to debate. Due to variations in experimentally obtained values for G, a number of postulates have been proposed which note that G may vary with time, and could be dependent on orientation, surrounding masses, even the curvature of space time!

    Complicating matters, experimental error in the determination of G is typically estimated at 1%, even with modern measuring equipment. Is G really a constant? Does it vary within this +/- 1% window? Is Newton’s Law of Universal Gravitation complete, or is there more to it? Recent studies continue to explore and debate these questions.
    [ATTACH=CONFIG]64[/ATTACH]
  11. FizziksGuy
    APlusPhysics Blogs and Forums have now been integrated with Facebook! Not only can you link your accounts, but you can simultaneously post any forum messages, blog entries, and comments to your Facebook wall by checking the "Publish to Facebook" checkbox at the bottom of your entry. Further, you also have the ability to "Like" blogs and forum posts... I'm interested to see if this encourages discourse and engagement by integrating a student favorite social networking site with classroom content.
  12. FizziksGuy
    Recently Frank Noschese, a NY physics teacher (Cornell) with a strong background in modeling and standards-based grading and author of the popular blog "Action-Reaction," was nominated for "Most Influential Blog Post" in the 2010 Edublog awards. The post, "The $2 Interactive Whiteboard," is a great resource for teachers looking to get into modeling and white boarding cheaply and easily. Help him win the award and, more importantly, spread the message about modeling in physics education by voting at: http://edublogawards.com/2010awards/most-influential-blog-post-2010/

    :einstein)
  13. FizziksGuy

    Collaboration

    By FizziksGuy,

    I had the opportunity to meet with a colleague, teacher, friend and peer on Wednesday, and I'm thrilled with how our breakfast (and work meeting) progressed. Having known each other professionally for close to 10 years now, from a time back before either of us entered education, it was a tremendous experience to sit down and talk about what's working in our classrooms, what we envision for the future, and start putting plans together to achieve that vision.

    Following breakfast, we settled down to work by looking over what had been completed so far at APlusPhysics.com. I was amazed at how closely our visions aligned... although I probably shouldn't have been since this colleague, in many ways, provided some of the grounding for this website project in the first place. We then spent the better part of four hours working on various parts of the website, each of us contributing in our own ways. I look forward to seeing what we can build together, and am very excited to have another viewpoint for input, contribution, and criticism as we move forward. Thanks Tom!
  14. FizziksGuy
    Had a busy weekend with lots of small successes on the APlusPhysics front... First off, finished up the first draft of the Regents --> Graphing Motion page (http://www.aplusphysics.com/courses/regents/kinematics/reg_graphmotion.html) with a couple more sample problems and an interactive Flash mini program demonstrating the relationship between d-t, v-t, and a-t graphs (thanks to Tom Schulte for the great graphics!!!).

    Also, spent some time on the phone with a physics teacher in Illinois working on an article that details our forensics and physics day activity -- received some terrific input and ideas that will definitely improve the article. Plus, it's always nice to make another friend in the physics teaching field.

    Then, got a start on the Regents --> Kinematic Equations page... lots of blanks to fill in and still tons of editing and re-organizing to do, but I'm feeling good about getting first drafts created and posted. Hopefully I can keep this momentum going with some time off during the holiday week.

    Finally, I'm pleased to see the "Homework Help" section of the website getting some use... not only are those asking questions getting the help they need without having to wait for class time, but those who are providing the help are reinforcing physics concepts. "The best way to learn is to teach!"
  15. FizziksGuy
    Didn't get nearly the progress made this weekend that I had hoped, as I'm definitely bogging down in the Regents Kinematics Content section of the website... taking some time to organize how best to deliver the material over an online medium. What seems so straightforward to teach in person, where you can fairly easily "hop around" to various topics to pull it all together, can get quite dicey when putting it in writing. :banghead) I also want to make sure I include plenty of sample problems, as I believe what will set APlusPhysics apart is its worked out problems. And of course, as you move into acceleration and then into d-t, v-t, and a-t graphs, graphics and animations can make all the difference. Guess I'm gonna have to brush up on these in the next couple weeks.

    In the meantime, though, as I have had a few 20 and 30-minute free spells over the weekend, I've cleaned up some of the Forum settings, fixed up the Physics In Action Podcast content page, added the Projects --> Speaker competition page, and converted my old Momentum WebQuest into the APlusPhysics template and added that under Educators --> Activities.

    Next Steps:


    Continue Regents content development
    Create a formal lab report guidelines page (not sure where best to place this yet...)
    Get the "About" pages started
    Add rating system to the APlusPhysics Forums
    Test out the Blogging System for use as a simple course management system
  16. FizziksGuy
    [ATTACH=CONFIG]45[/ATTACH]From NPR: Link Here
    A few years ago, physicist Jeff Harvey invited Eduard Antonyan to a game of poker at a friend's house. Antonyan was a graduate student of Harvey's at the time, in the physics department at the University of Chicago.

    "I invited Eduard to play because we're always looking for new victims," Harvey tells NPR's Guy Raz. "But it didn't exactly work out that well."

    It turned out Antonyan was pretty good.

    "He took my money," Harvey says. "We didn't invite him back after that."

    Antonyan would eventually find other ways to play. Today he plays online, where he says he hauled in $10,000 on his best night. But what's interesting about Antonyan and Harvey is not how much they win — but why.

    Big Game Theory

    Science writer Jennifer Ouellette (who was interviewed last year for the Physics In Action Podcast!) is married to a physicist herself. Like Harvey and Antonyan, her husband also plays poker — a connection that piqued her interest.

    "At first I thought it was just a fluke," she tells Raz.

    But a little research revealed there are a lot of poker-playing physicists, some of whom are pretty serious about the game.

    Physicist Michael Binger placed third in the 2006 World Series of Poker, winning $4 million. Two others, Michael Piper and Liv Boeree, competed last spring in a tournament in San Remo, Italy. Piper placed fourth, and Boeree won, racking up $1.6 million. Ouelette's husband, CalTech cosmologist Sean Carroll, entered a Chicago tournament in 2004 and, to his surprise, met three other poker-playing physicists, including Harvey.

    In a recent article for Discover Magazine, Ouellette says one reason so many physicists are playing poker — and playing well — is that their brains are particularly attuned to thinking about probability, statistics and modeling. In physics, those things are crucial. And in poker, they just might give you a leg up.

    "I mean — when you think about it — they build models of the world," Ouellette says of physicists.

    When her husband plays, she says, he's trying to model his opponents based on their style of play — from betting patterns to "tells."

    "He's using that to build a model — to predict them a little bit better." That model, Ouellette says, can help physicists make better decisions about their own play.

    Not Just Counting Cards

    Ouellette says that one reason poker is so intensely complicated — and thus suited for physicists — is that it's largely a game of probability.

    "If you think about throwing one die, for example, you've got six possible outcomes," she says.

    But add a second die? Suddenly your probabilities are a lot more varied: 36 possible outcomes to be exact.

    Now take your model 52 cards, Ouellette says, and you've got more than 2.5 million possible five-card combinations. And if you're playing Texas Hold 'Em — which uses seven cards? Around 133 million combinations.

    "The numbers get really big really fast," Ouellette says.

    Of course, there's no human brain capable of crunching those numbers mentally. But Ouellette says training in physics does help a player think about complex probability models in a deeper and more realistic way.

    Harvey, whose specialty is string theory, says there's another advantage that physicists might hold over their opponents. It's called "tilt" and refers to the way players let emotions get the better of them when things are going badly.

    "In physics, you have to be able to sit down and work on a long complicated calculation that may often take you weeks or even a month," he says. And sometimes, physicists have to throw that work out and start again when they realize their calculations are incorrect.

    "Being able to deal with extended periods of bad luck or things not going well is something that's also required to be a physicist," Harvey says. "I think there is an element of emotional control that perhaps physicists learn."

    Math Folds, Physics Holds

    It's been mathematicians, historically, who've held sway at the poker table, Ouellette says.

    John von Neumann, the famous Hungarian mathematician and founder of game theory, based his work on two-handed poker.

    "He was fascinated by the art of the bluff," Ouellette says. "And he founded game theory based on 'What do I think the other man thinks that I'm going to do?' "

    When it comes to physics, she says, mathematicians have done a lot of the groundwork. "Physicists are kind of catching up, and realizing that there's a lot of interesting theory at play here."

    And even though you may not have heard of most of the physicists playing poker today — there's one you probably have.

    "Einstein actually enjoyed gambling," Ouellette says.

    As legend as it, the father of relativity loved to play craps and blackjack in Las Vegas, where he once met Nick the Greek, one of the greatest poker players of all time.

    "Nick introduced him to all his gambling buddies — knowing that they wouldn't know who Einstein was — as 'Little Al from Princeton, controls a lot of the action around Jersey.' "
  17. FizziksGuy
    Hi Folks,
    If you don't get an option to upload an image file from your computer when you attempt to insert an image into your posts, you can enable this in the following way:

    Go to Settings > General Settings and set Message Editor Interface to "Show Enhanced (WYSIWYG) Editor."

    Next time you attempt to upload an image by clicking on the "Insert Image" button ([ATTACH=CONFIG]41[/ATTACH]), you should be given the option of uploading a file directly!
  18. FizziksGuy

    First Page Complete!

    By FizziksGuy,

    After several weeks of design as well as months of self-training courses, I have the first pass at an entire page for the content section complete! It took some work in Flash Catalyst, Illustrator, Dreamweaver, and MathType to put it all together, but I think it's looking swell for attempt #1. Check it out: http://www.aplusphysics.com/courses/regents/mathreview/reg_mathreview.html.
    :wave)
  19. FizziksGuy
    Work continues jointly on three fronts of APlusPhysics... I progressed through several more chapters of Adobe Illustrator CS5 Classroom in a Book (CIB), as it hasn't taken long to realize I need to greatly improve my illustration skills in order to adequately convey the message I want in the courses section of APlusPhysics.


    On off-CIB nights, I've been working through the text for the kinematics unit. More and more I'm realizing that I need to quit worrying about perfection in each section, and plow forward with the understanding that of course I'll have to come back and clean up, augment, edit, splice, etc.

    Finally, as we finished up our in-class unit on projectile motion, I took some time out to document our Forensics Day work... I believe the activity really stretched the students and gave them a new and unique challenge that is worth sharing with others. Toward that end, I wrote up a brief article and after giving it a few days and a few other pairs of eyes looking over it, may consider submitting to "The Physics Teacher" to share with others.

    Onward and upward!
  20. FizziksGuy

    APlusPhysics.Com

    By FizziksGuy,

    One of the goals of APlusPhysics.com is to provide students with the resources they need to be successful. As I'm sure you can all imagine, as educators we struggle with finding ways to set our kids up for success. And today's students face a wide variety of challenges that hamper their ability to learn through traditional means. Students who aren't in attendance, for reasons that may range from illness to family issues to special needs, are immediately at a disadvantage in technical classes in which content continues to build throughout the year on an ever-expanding foundation. Throw in the challenges of large class sizes (I'm outnumbered by students by more than 100:1), and regardless of how much time I'd like to devote to each of my kids, there's no way to meet everyone's needs all the time.

    Toward this end, APlusPhysics is designed to provide a "home base," of sorts, for all students to begin to learn to teach themselves. The forums provide an opportunity for discourse and an online student-supported "help desk," of sorts. Plus, any time you can get a student writing about what they know, they're solidifying their understanding and building critical thinking skills. If you can get them to teach others while they're at it, you've really built something special.
    The blog portion of the website is a great way to get students to develop their metacognition, writing about what they do and don't understand, creating an ongoing journal of their learning. It's also a great way to get them to really think about the essential questions in physics, organizing their thoughts to develop "big picture" conceptual understanding of what they're learning, and why.
    The main website, still under construction, will house key material central to each of the supported physics courses. I'm starting my work with the NY Regents Physics Curriculum, first, because I currently teach four sections of that course and the material I develop is directly useful to the majority of my students, and secondly, it's the simplest of the physics courses I teach, which provides a terrific sandbox for me to grow my web development skills, hopefully limiting my struggles to the technical side of web building, so that by the time I build the AP-C section out, I can balance content / pedagogical challenges with the (hopefully) less daunting technical challenges.

    I also see APlusPhysics as a great resource for the upcoming introduction of the AP-1 and AP-2 courses, being expanded out of the current AP-B curriculum. Currently it appears many of us AP physics teachers are holding in a quasi-limbo state waiting to understand exactly what will be included in each course, to what level, and how we can best integrate it into our school's offerings to provide the best possible learning experiences that will most benefit our students. But the College Board has been slow to disseminate information, updates promised in the fall have not been received, and the teachers continue to wait, as patiently as we can. My goal is to build up the AP-1 and AP-2 sections of the website so that when final announcements are made, we all have a resource we can turn to and utilize as we re-tool our physics programs.

    Finally, I want APlusPhysics to be a repository of materials for educators to share the best of our ideas, activities, challenges and successes. The Forum already has an Educators Only section, but I also want to populate the website with activities we can use to bring physics to life for our students, encompassing everything from projects and challenges to mini-programs such as the Semiconductor Technology Enrichment Program (STEP), providing students an introduction into the world of semiconductors, a discipline quite regularly neglected in educational communities despite its profound influence on our daily lives.

    So with that, allow me to welcome you to APlusPhysics. I'm hoping to continue utilizing this blog to document my progress in building this resource, both so you as customers / consumers / contributors can see what progress is being made and perhaps even help guide my work to make this a better resource for us all, to allow you to learn from my mistakes, and to organize my own thoughts around what I want to accomplish, and how I can make the vision I have for APlusPhysics a reality.

    Make it a great day everyone!

    --df

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