Spring Professional Development and Meeting ...Agenda
Ding Dong Doorbell Application
Team Problem Solving with Cooperative Learning
Constant Speed ?? (Activity)
Physics and the Men’s Pole Vault Record
Scales of Speed
Etcetera...

by Tony Wayne
by Tony Wayne
by Andy Jackson
by Andy Jackson
by Andy Jackson

Theme: waves light and sound
Who: Physical Science teachers and Physics teachers and professors    
When: April 25th (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/GMcCormickRoadArea.html The physics building is #41. You may want to park behind #38 off of stadium road. Do not park at the physics building. This is 24/7 permit parking. You may be towed is you park next to the physics building.
Why: ‘Cause it’s a fun way to become better at what you do! 
Cost: Free!!!
Sponsor: This meeting is hosted by the Physics Department of the University of Virginia and supported by funds in association with the Virginia Association of Science Teachers and Jefferson Lab.

RSVP IF ATTENDING – FIRST 24 GUARANTEED MAKE AND TAKE EQUIPMENT –  greg.mathes@fcps.edu
Agenda
8:30 – 9:00             Hellos and Juice, Coffee, and Danish
9:00 -10:00             Share session: Bring something to share. A demo, 30 copies of a worksheet or lab.
10:00 – 11:00            Dr. Bloomfield (from the University of Virginia) will speak about new lighting technologies.
11:00 – 11:30 VIP business (Officer elections and VAST participation)
12:45 – 3:00            Make and Take the junior “theremin.” (http://www.apogeekits.com/theremin.htm) The theremin combines areas of capacitance and electric fields with electronic sound production.  For a demonstration of theremin being played, see http://www.ted.com/index.php/talks/pamelia_kurstin_plays_the_theremin.html. The junior theremin is not as flexible as the typical theremin, but it just as much fun to play and demonstrate.
Bring a lesson, idea, piece of equipment- bring a friend! We will head to local restaurants for lunch together. (But as far as lunch costs – you’re on your own.)

Presenter: Tony Wayne
Albemarle High School , twayne[at symbol]k12albemarle.org

Va. SOL:
PH.12         The student will investigate and understand how to use the field concept to describe the effects of electric, magnetic, and gravitational forces.

Topic/Concept
A force is needed to move any object.
Force fields.
Magnetic repulsion

Materials
            1 - doorbell for Lowes or Home Depot. ($10)
            1 – pliers
            1 – wire cutters
            1 – piece of  wood to mount the doorbell on
            5 – 5/8” long number 6 screws
            9 – Volt battery

Safety Considerations
            Make sure the battery is not left somewhere in a position where the terminals are shorted.

Presentation

1. The completed unit is set up a station where students are asked to explain how a door bell works.
2. This could also be done as a classroom demonstration. A 9 Volt battery will ring the doorbell but it is designed for a 12 Volt battery. A 12 Volt battery rings the doorbell with more volume. A twelve Volt battery can be made from two six Volt lantern batteries wired in series.

How the physics is demonstrated
                  When the coils are energized by the battery they generate a magnetic field inside them according to Ampere's rule. The metal rods inside the coil are steel and are attacted. This pulls hte rods into and through the coil to hit a bell. When the current is turned off, the spring wrapped around the coil pulls the rod back into place and overshoots the equalibrium position and hits the other bell. before coming to a rest in the equalibrium position.

Construction

by Tony Wayne

At some point in almost physics unit, students will be working on solving word problems. I’ve come up an activity that encourages team problem solving. I use this process as part of a review for a test for many units. Here is how it is done in a kinematics unit. First I pick 4 or 5 problems for the students to work on. I choose problems that are not solved the same way but are solved using the unit’s concepts and methods. The problems are not new but they are also not identical to any homework or classwork. Typically I use this type of activity to hone students skills and knowledge. (It also makes for a good review for some AP physics topics.) I put together packets of papers. Each packet consists of 3 sheets. Each sheet has the same questions but different numbers in the problems. One third of my class receives page one of the packet. One third receives page 2 and the final third receives page 3. I make a few page 4’s to handout to fill in the gas in numbers. Students do this page for homework. I give a small grade a little larger than my typical homework grade if they completed the assignment by the next class.

This activity is the easiest to create when using a spreadsheet application like Excel to set up the worksheet. Since all the problems solve the same, each column could represent an activity sheet. The rows represent the givens and answers. This makes playing around with the numbers from worksheet to worksheet a lot easier. This sounds like a lot of work for one individual, but if you work collaboratively in a PLC group, either within your building or district you could divide up the tasks by units or even the number of questions within an activity. Go to http://vip.vast.org/teamproblemsolving to see an example. The spreadsheet is just an image wtihout any answers. It does show you how the speadsheet is set up. (Why no answers? Since my students know how to search the web, I did not want them to find the answers .)

The cart provided is advertised as a constant speed cart. Conduct an experiment to test this claim. Materials – meter sticks, constant speed cart, 4 stop watches Collect the data you need to test the manufacturer’s claim of a constant speed. Display this data and your conclusions on both the white board and on paper to turn in. Determine the average speed of the cart and describe just how constant its speed is. Display this on both the white board and on paper to turn in. The lab above represents another step I’ve taken to allow the student to have more control of his/her own learning. A step towards more of an inquiry style lab and a step away from cook book style labs.  I conducted this lab on day three of my course. The only instruction the students have had at this point is a lab reviewing measurement and significant figures, and a lab regarding experiment design.

The students began playing with the equipment and discussing how they were going to conduct the experiment. There were five groups of four students in the room. After a little bit of time (maybe five minutes) I noticed that four of the five groups were using the same approach. They had marked off a measured distance and would put the cart at the start and time how long it took the cart to complete the distance. They would then record the time and repeat. The working assumption seemed to be that if the cart completed the given distance in the same amount of time over and over, then it was traveling at a constant speed. I interrupted their work to provide the following example: “If a runner completes the 100 m dash consistently in 12.0 s, does that mean he runs at a constant speed the whole time?” This seemed to instantly click with all the students and all groups immediately broke their distance down into intervals which they timed.

When the students reported their results to each other, some groups had calculated speeds by dividing the distance interval by the time interval while others just reported the amount of time needed to move through equal distance intervals. Most groups identified any variance as proof that the cart did NOT have a constant speed and were ready to sue for false advertising. This led to a useful conversation about measurement uncertainty that was NOT expressed by the significant figures. For example the stopwatches displayed times down to the hundredth of a second, but the students quickly agreed that their procedure did not allow for that degree of precision.  The end product was that all groups were able to express the average speed of the cart and provide a bracketed range for that speed. A common form for communicating this was “23 cm/s ranging from 20 cm/s to 27 cm/s” where the groups often cited the extremes of speed they measured as being the limits of the range.  At the conclusion of the presentations to each other there was still debate about if the carts truly had a constant speed or not. I do love a good physics argument.

Buggy image from
http://www.physicstoolboxinc.com/p-62-constant-speed-buggy.aspx (The page will open in a new window.)
(Available for $6 each from the Physics Toolbox)

Let’s be reasonable – teaching constant speed and establishing an understanding of scales of speed.

Early in the physics course it is important to establish problem solving routines. One of those routines should be to check your answer for reasonableness. Many students arrive in my physics class with an understanding of metric units of length, and time of course and to a lesser degree of mass. However, I find that few of my students have a good visualization of speeds in m/s. To help with this I present a power point called what does 6.7 m/s look like? It is quite easy to put together and I use it right after we do a lab on constant speed where we measure the time for a person walking as they cover a 10 meter distance. We record the cumulative time at every meter interval and I use it to introduce graphing of distance vs time. At this point we have established that someone in our class is capable of walking a fairly constant speed and it is very close to 1.0 m/s.

The power point starts with a slide showing the value 1.0 m/s. After a click it displays 1.0 m/s and shows an image of a person walking. The next slide displays 10 m/s. After a click it displays an image of men’s Olympic 100 m dash. I work my way up to 100 000 m/s by powers of ten. The table below indicates the details.

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It doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong.
– Richard Feynman, talking to his students in PBS’s NOVA show, The Greatest Mind Since Einstein