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VIP’s mission is to foster communication among teachers of physics and physical science as well as to provide unique learning experiences for teachers and their students. Next Meeting Location: UVA’s Physics Building Date: March 31, 2001 Time 9:00 A.M.
Please Reply ASAP if you will be attending the Spring VIP meeting. Email &emdash; asjackson@earthlink.net or mail a reply to Andy Jackson Harrisonburg High School Help us keep our lists current. New address? 395 South High Street Not coming in your name? Let us know. Harrisonburg, VA 22801 Please include your Name_____________________________________ School_____________________________ Mailing address email
There are two ways you can enjoy VIP from your computer at home or at school. There is the VIP web site maintained by Tony Wayne. You can access this at www.vast.org/vip/. Tony has collected past newsletters, and amassed a great collection of physics links all at your fingertips. The second, and newest way, is through our e-groups account. If you become a member of the Va-Inst-Phys group, then you can ask that bothersome question or recommend that great book anytime you want. I have thoroughly enjoyed "listening" to and participating in the various conversations that have gone on. Rarely does a posted question go unanswered. If you’d like to subscribe, then send an email to va-inst-phys-subscribe@yahoogroups.com and our moderator, Ron Revere, will add you to the list. No junk mail, just a pleasant amount of physics education related conversation.
This school year VIP will have had three meetings. Our first was hosted by the Virginia Science Museum in Richmond on September 23. We were provided with a conference room and free access to the museum and an I max movie. We got so tied up in discussions of physics teaching that many had to head home before touring the museum and no one made it to the movie. Those that did stay and check out the museum enjoyed discussing the misconceptions that the exhibits confronted. Our second meeting was held in conjunction with the VAST conference in Roanoke on November 10 and 11. Here VIP provided two presentations at a conference where there was a much stronger physics presence than in past years. Thanks to all who helped at our Table top Physics and our VIP Share Session. Both were fairly well attended and we received some thanks and praise from attendees. If you haven’t attended a VAST conference in a while, let me encourage you to do so. (and maybe present for VIP!)
As I started thinking about what labs, demos or lessons I could put into this issue of the newsletter, I encountered a rather interesting web of events that I had never really fully put together before. In my mind it exemplifies why I value VIP, and why I put time and energy into it. As I was sorting through labs & demos I do, and haven’t written up for VIP, my mind came to rest on a couple of days worth of lessons I do with regard to the creation of the universe. At the end of the lesson, after we have discussed the concepts of redshift, 4 K background radiation, Big Bang, etc, I read them a chapter from Mr. Tompkins In Paperback by George Gammow. I’ll explain the lesson later. My point here, is how I came to own the book. In the spring of 1985 I was a Junior taking a course in Methods of Science Teaching at James Madison University. My professor, Dr. Petus, required us to "teach" a lesson to our classmates as if they were the students we would be teaching in a couple of years. I decided I would teach a lesson on pressure. I knew one of my physics professors, Dr. Serway, had a bed of nails he had built and had used to teach this topic in a course I had earlier. I asked If I could borrow it and Dr. Serway consented. The lesson was a success. In the fall of ’87 I built my own bed of nails for my physics classes at Fauquier High School. About three years later a former student of mine was taking a physics class during a summer session at UVA. The professor was describing the physics associated with laying on a bed of nails. The student described how her high school physics teacher had actually laid on a bed of nails. The professor, Mani, looked my number up and asked if he could borrow the bed of nails for his class and for details on how to build his own. I agreed. When Mani returned the bed of nails he included a gift of thanks for me - Mr. Tompkins In Paperback by George Gammow. The lesson I teach this year (and am passing on to you) is due to the free and unselfish exchange of teaching ideas. Thank you Dr. Serway, Dr. Petus, my student whose name I can’t remember, and Mani. Your teaching and generosity is still affecting students 16 years later. I invite you to join and extend the web of sharing and educating and participate in VIP. Share your ideas and bring some new ones home. Who knows how many people you may inspire? Sincerely, Andy Jackson Physics & Astronomy Teacher Harrisonburg High School
An Elementary Capacitor Application by Tony Wayne
I’m always looking for a good application of textbook theory. This article will describe in simple terms an application of a capacitor. In the description of the circuits the charge flow is described in terms of positively charged particles because that is the definition of current. It ignores the fact that in reality negative charges flow through circuits. One of the interesting applications of a capacitor as a power source. In this manner of operation, capacitors are like batteries.
Conceptually, batteries are devices with separated charges. The charge separation occurs chemically. Charges are moved from one pole of the battery to the other pole when they travel through a circuit. Along the way each charge loses energy to the circuit. Each elementary charge loses an amount of energy in electron volts, eV’s, equal to the voltage of the power source. Once the other battery pole is full., no more charges move. No more charges move and No more energy is delivered to the circuit. At this point most people call the battery "dead." To recharge the battery charges are removed from one pole of the battery and given to the other pole. A capacitor can behave the same way as a battery. After all, a capacitor is nothing more than a device with separated charges. One plate has a net positive charge while the other has a net negative charge. The positive charges are drawn through the circuit to the negatively charged plate. Along the way they deposit some energy to the circuit. The amount of energy they have depends on the energy of the charges that were placed on the plates. One way to place charges on the plate is to use a battery. If the plus and minus terminals of a 4.5 volt battery were touched to the plates of a capacitor, then each elementary charge that was placed on the plate will have a 4.5 eV’s more energy than the charges placed on the opposite plate. How many charges can be stored and used by a parallel plate air capacitor is limited by the size of the plates. And capacitors cannot hold as many charges as a large battery. The real question is, "Why use a capacitor instead of a battery if a battery is still needed to place charges on the capacitor to begin with?"
Capacitors discharge and recharge very quickly. Capacitors can be recharged many thousands of times before noticing a change in performance. Here are two simple examples of capacitors as energy storage devices.
Example #1
Many car’s electrical systems are not designed to deliver the power demands of today’s high powered, body thumping, stereo systems. When these systems try to produce loud bass notes, the necessary power is drawn from all the car’s other electrical systems. This is why the lights in some cars dim when the radio produces loud bass notes. The power delivered to the amplifier drawing the power needs to be augmented. This is done with a large capacitor placed in the power line between the car’s battery and the amplifier.
Because the X-V Racer™ uses a DC motor, the motor can be used to generate electricity and thereby put charges back on the Hotwheels™ car. This can be done by taking a drill, turn it in on high and holding the wheels of the car to the drill’s chuck. A high speed roto tool, such as a Dremel™, may work even better. Links for further investigation For a great shockwave animation of what happens chemically inside a battery follow these links: http://www.duracell.com Click on the "Fun & Learning" link. For some details technical data on some batteries go to http://data.energizer.com/
There are three main particles that have to be dealt with, and poker chips come in three colors. In Alpha decay an alpha particle ( 2 p+ & 2n ) and gammas are released. A sufficiently large stack of red ( p+ ) and white ( n ) can be 'decayed' into the alpha particle and decay product. A chalk squiggle makes a gamma and the students enjoy being able to mark on table or lab counter tops. Beta decay can be modeled with red for p+ and a red and blue for a n. The neutrino can be represented by the separation of the red & blue n, with the blue as an e- and the process separating them as the neutrino. Unless you have a lot of poker chips, you can't model any actual decay series so you have to pretend a radio-isotope of a smaller atom and invent a decay series. If I have students who find this insufficiently challenging then I give them a decay target, a particular element and have them decay to that. For example the students can be given a stack of red & white protons & neutrons, and some loose red & blue ( which can be pair ( 1 each red & blue ) substituted for a white ( n ). Then I tell them to decay it to C-12 or B-11.
Also poker chips serve well for 1/2-life models. If you have sufficient numbers, the students can stack some, 2^n quantity of chips. I have mine start with a stack ( 16 ) all white, each chip representing an atom of radioactive material. They then construct a stack of = mass ( height ) but with 1/2 of them blue and then continue the steps until they've constructed a set of stacks of = 'mass' but with each succeeding stack having 1/2 the proceeding stacks 'radioactive' chips. If not used as a static model ( one stack all one color, the next with the top 1/2 white, bottom 1/2 blue, the next top 1/4 white, 3/4 blue then top 1/8 white and 7/8 blue etc), then they have to mix up the chips so the 'stable' chips are not in one part. Poker chips are useful because they're cheap, easily obtainable, relatively hardy and can be marked or painted for additional applications.
Name____________________ Period_____ By Andrew Jackson Harrisonburg High School
Purpose: General - How do meteorites form craters? How do different variables that meteorites have, affect the size and shape of the crater formed? Lab Specific ; What does the diameter of the crater formed in sand by a ball depend upon? Materials:
Procedure:
Mass (g) trial 1 trial 2 trial 3 average
Right now you have a graph of Diameter vs Height. Each of these is raised to the 1st power. Manipulate the exponents until you create a linear graph with a good fit. Use whole numbers for the exponents and keep them as small as possible. Why are these exponents what they are? What quantities does it indicate are involved? For example, real craters don’t fall from "a height". How do the answers to question 7-9 support your hypothesis? Write a paper that answers these questions. Provide a graph that supports your answers .
Roundtable Practice- Polly Brizzi Divide students into groups of three or four and provide each student with a piece of graph paper. Then hand them the following instructions. Graphhopscotching: Imagine the following: You are sitting in a car at a red light when the driver steps on the gas because the light has changed to green. You don’t feel like you’re being pressed back into your seat, but you can see the speedometer readings increasing for the next five seconds (t=0 to t=5). Having reached the speed limit and being a law-abiding citizen, the driver continues at the speed limit for the next five seconds (t=5 to t=10). The car now enters a zone with a lower speed limit and the driver adjusts accordingly over the next five seconds (t=10 to t=15) with enough control that you don’t feel like you’re being pushed toward the dashboard. You are now traveling at the "new" speed limit for the next five seconds (t=15 to t=20) until the driver notices that a traffic light ahead of you has just turned yellow. The drive now begins to prepare the car for stopping, gently reducing the speed to zero in five seconds (t=20 to t=25) and stops safely.
In conjunction with the IMPACT! Lab, I have my students check out a web site Thomas O’Neill shared with us at VIP at VAST last November. The site is http://janus.astro.umd.edu/astro/impact.html The "Big One"
Middle School Math/Science Teachers
The University of Virginia and Virginia Commonwealth University are in the process of receiving funding from the National Science Foundation Graduate Teaching Fellows program to offer a master's degree in math and/or science for middle school teachers. A total of 24 outstanding middle school teachers will be recruited to begin in June 2001 as students in graduate programs at Virginia Commonwealth University (16 students) and the University of Virginia (8 students) and to serve as Graduate Teaching Fellows. The program is designed for teachers to develop
Teachers will spend one academic year full time at either UVa or VCU on-leave from their teaching position and three summer semesters. They will receive a $6000 stipend for each semester and full tuition and fees (in-state) support for all five semesters ($30,000 total stipend). During the period of their full-time appointment the Graduate Teaching Fellows will:
After the period of the appointment, each Graduate Fellow will be considered for selection as a member of the Clinical Faculty at VCU or UVa. Those who are appointed may serve as lead teachers within their schools and serve as supervising teacher for student teachers and for practicum students within the Fellow’s middle school. The first cohort of teachers will begin June 2001 and spend the 2001-2001 academic year full time at either VCU or UVa. They will be in the program for the summers of 2001, 2002, and 2003. The second cohort will spend the 2002-2003 academic year full time, but may begin taking classes in summer 2001. UVa and VCU will jointly teach most of the courses. For more information to apply at UVa look at our website at http://k12.phys.virginia.edu or contact Steve Thornton at 804-924-6808 (stt@virginia.edu) or Loren Pitt at 804-924-4926 (ldp@virginia.edu) and at VCU contact William Haver (ext. 123), Reuben Farley (ext 121), or Karen Murphy (ext 155) at the number 804-828-1301.
The University of Virginia is once again offering its summer program in professional development for high school physics and middle school physical science teachers. Funding will be available for summer 2001 for stipends and housing at UVa from a SCHEV Eisenhower professional development grant. Participants are urged to request partial funding for stipends, tuition, and housing through their local school systems, which may have Virginia Department of Education's Training Initiative Grants or Eisenhower funds. The summer program is from July 9 - August 3, 2001 in Charlottesville. This summer's courses include a 4 credit hour lecture course on mechanics, heat and thermodynamics, and fluids and a separate 3 credit hour laboratory-type course teaching best practice pedagogy that utilizes graphing calculators and computers with probes. Opportunities exist for recertification, physics teaching endorsement, or graduate credit towards our Masters of Art in Physics Education degree program. Enrollment is limited, and preference will be given to teachers taking both courses. The University of Virginia Department of Physics and School for Continuing and Professional Studies is cooperating to bring this program to Virginia’s schools and teachers. For tuition information and to register for classes, call the UVa School of Continuing and Professional Studies at 804-982-5313. For more information about the program, see the website at http://k12.phys.virginia.edu or contact Richard Lindgren (804-982-2691, ral5q@virginia.edu) or Stephen Thornton (804-924-6808, stt@virginia.edu).
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