Winter Newsletter 2006 (or is it spring yet?)

Hi all! I hope your 2005-2006 school year is going great. For many of you, you know all about what the VIP newsletter is – skip ahead for the good stuff.  For some of you, you just found this newsletter and haven’t a clue. If you are in the first or second group – Come Join US!  This newsletter is just the tip of the iceberg! (hmmm, there must be lesson here somewhere…) To get the full effect of the Virginia Instructors of Physics, you need to join us on the web at http://www.vast.org/vip and join us in our list-serve discussions by clicking on the “VIPs email discussion list” button. Once you’ve experienced virtual VIP, then you just MUST experience the real deal. Come join us at our Spring Meeting and our Fall Sessions at the Virginia Association of Science Teachers Professional Development Institute. Hope to see you in Charlottesville soon and in Richmond next fall!

Spring Meeting Information

Who: Physical Science teachers and Physics teachers and professors    
When: April 29th (time agenda below) 8:30 – 4:00
Where: the physics building, Jesse Beams Laboratory. There is a good web map at http://www.virginia.edu/webmap/.  Click on “G” The physics building is #41. You may want to park behind #38 off of stadium road.
Why: ‘Cause it’s a fun way to become better at what you do! 
RSVP BY SENDING AN E-MAIL TO ajackson[AT SYMBOL]harrisonuburg.k12.va.us IF ATTENDING – FIRST 25 GUARANTEED MAKE AND TAKE EQUIPMENT
Agenda
8:30 – 9:00      Hellos and Juice, Coffee, and Danish
9:00 -10:00      Business and election of officers
10:00 – 11:30  Share Session
12:45 – 4:00    Make and Take on Electricity and Magnetism

At the spring meeting we will concentrate on creating a DOZEN different labs and demonstrations related to electricity and magnetism. Participants will construct and use the equipment and participate in a mini-lecture and discussion on the theory, physics, and pedagogy behind the equipment.

Fall Meeting

Once again we will have our fall meeting in association with VAST.  This will be in Richmond on November 15th – 19th. As part of our business meeting at UVA we will discuss our presence at the VAST PDI.  Last fall VIP and VIP members were responsible for five well attended sessions. Thanks to all who made it possible!

At the VAST meeting awards are given to outstanding teachers. This fall VIP nominated Nancy Hoover for the "Award for Outstanding Teaching" in Physics and Greg Corder for the "Award for Outstanding Teaching" in Middle School Science. Both Nancy and Greg have been active members of VIP and have contributed much to our organization. The little bit that we know of them from our twice-yearly meetings and occasional emails has shown them to be wonderful teachers. The letters that we received from their administrators to support our nominations showed that we had only seen the tip of the iceberg.  I'm proud to say that VAST chose both Nancy and Greg to recognize for their outstanding teaching.

Congratulations Greg and Nancy and thanks for sharing with the VIP community and thanks for being there for your students.

VAST & VIP

Let me take a few lines to explain our relationship with VAST. VIP is an official affiliate of VAST. By being an affiliate, we have a non-voting voice on the VAST board – Andy Jackson, representing VIP. Andy is also the Physics Standing Committee Chair on the VAST board and is thus a voting member of the board. For the last several years VAST has provided seed money for our Make and Take sessions at our spring meetings. Last year and again this year, VAST is supplying VIP with $700 to purchase materials for our spring meeting.  As VIP has matured and grown, we have been held up as a model organization. Your efforts in supporting each other in your profession are being noticed!

Tip of the Iceberg (I told you there was a lesson!)

http://www.ed.mtu.edu/esmis/id190.htm   Great lesson here. Website claims it’s for 6th – 8th. I was thinking it would be great in a physical science class. We all know that lots of an iceberg is beneath the surface, but how much? This guided inquiry lesson challenges the student to find a way to determine what percent of an iceberg sits above the surface of the water. The lesson takes this investigation and leads the student to a discussion of density and the question of how the “iceberg” would float in salt water.  If that lesson fits your physical science class, then maybe this webquest fits the bill as well. http://express.howstuffworks.com/wq-iceberg.htm

http://commons.wikimedia.org/wiki/Image:Iceberg.jpg Accessed feb. 27, 2006.

Hooked on Physics !

Robert Hooke (of discovering the cell fame) also determined something important in physics. He was attempting to design a clock that used a spring instead of a pendulum. In the process he needed to determine the nature of the force of a spring.  In this experiment we will attempt to reproduce his findings.

Materials             Set of masses             Spring             Ruler             Ring stand Procedure             Set up the ring stand and spring as shown             Hang a mass on the spring             Measure the change in length of the spring             Record the mass, weight of the mass, and the change in length of the spring

Analysis
            Plot a graph of Force vs Stretch of spring. Normally the Force would be on the
X-axis since it is the independent variable, but plot it on the Y-axis this time. This is because the slope has a particular meaning in this format.

            Fit a best fitting straight line to the data and determine the equation of the line.

Questions
            The slope of this line is known as the spring constant for this spring. What is the spring constant of your spring. Make sure and use Graphical Analysis to present the value along with its uncertainty.
Compare your spring constant with the value determined by two other groups. How do they compare?  How do the springs compare? What does this tell you?

Extension

Conduct an experiment to see if Hooke’s law applies to something besides a spring. You may select any material or object that stretches.  Write this experiment up in a formal manner.

A Conundrum ? 

“A sealed container contains a live bird. With the bird at rest on the bottom of the container, the system is weighed on an electronic balance. The bird is startled by a loud sound and flies and hovers in the air. How is the reading on the balance affected?”

Materials

• 1 kick Dis’
• 1 sealable container big enough to hold the kick Dis’
• 1 electronic balance good to the gram.

Students are given the problem stated above to consider. The Kick Dis’ ,the container, and the lid  are all massed with the Kick Dis’ turned off.  The Kick Dis’ is placed in the container with the lid under the container and students are asked to predict the mass reading when it is turned on. Reading is made and discussed. The Kick Dis’ is placed in the container, turned on and the lid is pressed on. Students are asked to predict mass reading. Reading is made and discussed.

How the physics is demonstrated

In this demonstration when the Kick Dis’ is turned on and placed in the container with the lid beneath the container, the mass reading is greater than recorded when the Kick Dis’ was turned off. When the Kick Dis’ is turned on and in the container with the lid, the mass reading is equal to what it was when the Kick Dis’ was turned off. Without the lid on, the air pushed down and is reflected back upwards and acts as an additional force pressing down on the balance. When the lid is on, this force pushes equally down on the container and up on the lid and introduces no additional external force.

Kick Dis’ is an Estes product and can be found for between $30 and $40 through a number of vendors.

Teaching Free Body Diagrams through a “Stations” Approach

 

I have observed that the talent of creating correct free body diagrams, or force diagrams, is a skill that needs a bit of practice. Obviously, for a lot of mechanics problems, if the student can’t get the forces sorted out successfully, he is stuck. Let me share with you the way I now tackle this. One thing I do that is a bit unorthodox is I don’t deal with vectors and vector math until a good ways into the course. I teach Newton’s laws, acceleration, frictions, etc all in a linear, two dimensional context.   Then after I teach universal gravitation and circular motion I get into the trigonometry of vector addition.  I work the students through a series of steps of vector addition and the basic math that is necessary. Then I introduce them to the concept of static equilibrium and the need to create a free body diagram.  I start this process with whole group instruction on a very standard issue problem.

I draw the picture to the left on the board and talk them through creating a free body diagram. I do not solve the problem, or even create a problem at this point, just create the force diagram.  After talking to the students about the process we go into the lab. In the lab I set up seven different ‘assemblies’ for the students to practice drawing free body diagrams. I explain that each diagram needs to be on its own sheet of paper to avoid what I call ‘post stamp’ sketches.  The students are to create the force diagram and measure and label the angles for all the forces. Our rules at this point are “if it looks vertical or horizontal – it is. If it looks like a 90 degree angle – it is”. Three of the ‘assemblies’ are shown below.  After the students have successfully completed the force diagrams, I then put up the “Eat at Joe’s” picture again and turn it into a static equilibrium problem by defining the mass of the sign and the angle for the chain and show them how to solve for the tension in the chain. The students are then assigned to work their way through the seven diagrams they have constructed, solving for the force provided by the part of the ‘assembly’ that was tagged with a post-it note. The students are encouraged to work together on these solutions. The difficulty of the solutions can range from quite simple to extremely difficult – so think ahead about what you build. (Note the ring stand, inclined plane, and force table – Ramp and force table are labeled w/ NDEA 1969!  I think the ring stand is older!  See you in C’Ville on April 29th!

Cool Questions: Universal Gravity

by Tony Borash
" Long, long ago, in a galaxy far, far away, the planet of Tatooine revolved around the twin yellow suns Tatoo I and Tatoo II.  Referring to the diagram below, a.) find the net force acting on Tatooine when all three heavenly bodies are aligned, and, b.) assuming that Tatooine’s orbit is centered halfway between the two stars, find Tatooine’s tangential velocity at this exact moment in its orbit.?

Tatooine ANSWER

Fluids

by Andy Jackson

r = 1.00 g/cm3 for water                       r = 11.34 g/cm3 for lead           
r = 1.03 g/cm3 for sea water (avg)        r = 2.70 g/cm3 for Aluminum
r = 0.929 g/cm3 for cooking oil            r = 0.90 g/cm3 for wood

A graduated cylinder that can be read to the 0.5 ml is filled with water up to the 75.0 ml mark.  There are three cubic objects. Each object measures 3.00 cm to a side. One is lead, one is aluminum, and one is wood. Tell what the cylinder will read when each of the objects is placed in the graduated cylinder separately.  Explain WHY each reading will be what it is. Which, if any, of these readings will change if the fluid is cooking oil?

I would love to publish a newsletter more often with MORE CONTRIBUTORS! Feel free to email me your article or contribution to ajackson@harrisonburg.k12.va.us You can count towards recertification and you’ll get your VIP dues covered for the year!

Thanks for the great job you do! Keep it up and keep improving - Andy