High School Mathematics-Physics SMILE Meeting
09 November 2004
Notes Prepared by Porter Johnson

Leticia Rodriguez [Peck Elementary School]           Interactive Fractions 
Leticia passed around sheets showing wheels divided into halves, thirds, fourths, sixths, ninths, and twelfths, as well as a spinner for generating the numbers 1, 2, 3, 4, 6, 9, and 12.  We were to spin twice (say 3, 12), form a fraction by putting the smaller number over the larger (3/12), and color that fraction in one of the wheels.  The person who first colors all the wheels is the winner.  What a neat way for students to learn fractions!

Very interesting game, Leticia!

John Scavo [Kelly HS]           Stuff
John first showed a remote control car, Tip Car, obtained by Santa Claus for about $10 at Walgreens. The car moves, spins, turns, and backs.  It is closely related to a more expensive toy, the Rewinder, manufactured by Tyco Corporationhttp://www.tycorc.com/default.aspxA marvelous Christmas present for children of all agesJohn also showed us a Magnetic Construction Toy [http://www.rogersconnection.com/index.html], as well as a wind-up, spining top that could be tossed and caught from paddle to paddle while spininng.

Good toys, John!

Roy Coleman [Morgan Park HS,  physics]           Rocket Launch
Roy announced a rocket launch (outdoors) at the Williams Science Center of Chicago State University next Monday, 15 November 2004.  The rocket launch will be done by veteran SMILE participant John Bozovsky and Mel Sabella of Chicago State University: Tel 773-995-2172..

Happy (rocket) trails, Roy!

Dianna Uchida [Morgan Park HS]           Neat Book
Dianna recently obtained the book Science Explorer [ISBN 0-7566-0430-3] for $12.97 at COSTCO.  This book, published in 2004 by DK Eyewitness Books [http://www.dk.com], shows a beautifully illustrated and annotated variety of historical apparatus, and is rather wide-ranging.  She cited the example of development of bronze tools for axe blades, swords, and (ouch!) razors in primitive society. Thanks for the information, Dianna!

Fred Schaal [Lane Tech HS  mathematics]           1 +1 = 1 
Fred remains puzzled as to how the Volume and surface Area depend upon the radius of a black hole.  Apparently, the standard formulas

V = 4 p R3/ 3
A = 4 p R2
do not apply.  Why? Porter Johnson explained that, in a curved space such as near or inside a black hole, distances are not merely equal to changes in coordinates, but one must take into account the curvature of space. For example, the surface of the earth is curved, and the standard formula for the area of a triangle (on a plane) is incorrect when the triangle is on the curved surface of the earth. For additional information see the paragraph The Size of a Black Hole on the website http://curious.astro.cornell.edu/question.php?number=160/Bill Colson told us of the following statement by Stephen Hawking:
"God not only plays dice. He throws them where they can't be seen!"
Good question, Fred!

Ann Brandon and Debbie Lojkutz [Joliet West HS, physics]           Accelerometers 
Ann and Debbie first showed us the Peanut Butter Jar Accelerometer, and demonstrated how it works.  They then gave each of us a plastic straw (with a small slit at one end), a piece of string, a big paper clip, and an arrow drawn on a small piece of paper.  We tied one end of the string to the big paper clip, and tied a knot at the other end.  Then we pushed the knotted end of the string through the unslit end of the straw and out through the slit end.  Then we pushed the string through the slit, so that the knot would be caught.  Next we attached the arrow to the paper clip, so that it pointed at the straw.  We had thereby constructed our very own accelerometers, which we tested.  They worked!

Ann and Debbie handed out the following sheet:

    Accelerator Homework
  1. Take your accelerometer with you for a ride in the car. (Please -- have someone else drive!)
    When going forward, what happens to the accelerometer when the driver (a) steps on the gas pedal? (b) steps on the brake?
    When going in reverse, what happens to the accelerometer when the driver (a) steps on the gas pedal  [What is the indicated direction of acceleration?] (b) steps on the brake [What is the indicated direction of acceleration?]
    What happens to the accelerometer when the driver makes a right-hand turn? [What is the indicated direction of acceleration?]
    What about a left-hand turn? According to your accelerometer, what is the direction of acceleration?
  2. Teach your mom or dad about using the accelerometer to determine (1) the direction of acceleration and (2) whether acceleration is taking place. Have your parent fill out their report.
  3. Dear Parent,
    It's Physics Demo time for your child. They have learned a concept in Physics that is easily demonstrated and their assignment is to demonstrate and explain this concept to you.  To verify that they have done this, you should write a couple of sentences describing what they (the student) did and said.  The very bottom of the page is for any comments about this assignment or for a message to me.  Would more of these "student teaching" assignments be OK with you?  Thank you for your cooperation.
  4. My son/daughter taught me about using his/her accelerometer to determine the direction of acceleration. This is what I learned:

Ann and Debbie also called our attention to two items in a recent catalog of Frey Scientific:  The first item, an Impact Car (#05578611, $7.75) [http://store.schoolspecialtyonline.net/OA_HTML/xxssi_ibeSearchResults.jsp?type=search&minisite=10029&query=impact+car] permits the measurement of the maximum force at impact.  The second, a Large Lens Kit (#05527379, $64.55) [http://store.schoolspecialtyonline.net/OA_HTML/xxssi_ibeSearchResults.jsp?type=search&minisite=10029&query=large+lens+kit] contains several lenses with magnets on their backs, which are suitable and convenient for blackboard optics.  

Thanks, Ann and Debbie!

Rich Goberville [Joliet Central HS,  physics]           More Stuff
Rich showed us his Christmas gift (from himself!), a light-up tie obtained from the Enlighted website http://www.enlighted.com.There are various other types of novelty clothing available on that website.  Very thoughtful of you, Rich! Rich also showed us a Magic Floating Snowball (Bernoulli Machine) that he obtained for about $12 from Menards.  When the switch is turned on, a fan blows air out of a funnel-shaped hole, causing a light ball to be lifted. Neato! Finally, Rich passed around a sort of Chinese yoyo, which illustrates Newton's First Law; namely, it keeps on moving once it gets going.  This device, which consists of a long strip of paper attached to and wrapped around a shaft.  It should not be confused with the real Chinese Yoyohttp://www.chineseyoyo.org/index.htm.

Toys that show physics! Very interesting stuff, Rich!

Bill Shanks [New Lenox Environs,  at large]           Water Source Detector?
Bill brought in a device with prongs that required batteries, which can be inserted into a soft medium or fluid It looked like a very large black plastic fork, with two metal-pointed tines.  The device has the labels Well, Medium Well, Medium, Medium Rare, Rare, and Very Rare.  It is not used to determine the source of water, but to give some indication as to the temperature.  The device, a Thermal Fork, was obtained at Walgreens for about $10.  How does it work?  The following answers were given:

Thermocouple, Thermistor, Ohm Meter, Thermoresistor

For additional information see New Types of Food Thermometershttp://www.amazon.com/Taylor-1482-Digital-Fork-Thermometer/dp/B00009WE44 A Very interesting question, Bill!

Monica Seelman [ST James Elementary School]           Divisibility Test for 7 
Monica began by reviewing these simple rules to determine whether a given number is divisible by 2, 3, 4, 5, 6, 8, 9, and 10:

Number Divisibility Criterion
2 Last digit 2, 4, 6, 8, or 0
3 Sum of digits divisible by 3
4 Last two digits divisible by 4
5 Last digit 0 or 5
6 (Divisible by 2 and 3)
7 What about divisibility by 7?
8 Last three digits divisible by 8  
9 Sum of digits divisible by 9
10 Last digit 0
To consider divisibility by 7, Monica wrote down the number 1862. First, take the final digit (2), double it (4), and write it down under the second digit (6), and subtract that from the number with that final digit excised: 186 - 4 = 182. Then, repeat the process, taking the new final digit (2), doubling it (4), and subtracting that from the number with the final digit excised: 18 - 4 = 14. The number 14 is divisible by 7, so the original number is, as well. How can such a process possibly work? Let us write it out in detail:
1862 1862

- 4 OR - 42

--- ----

182 1820

- 4 - 420

-- ----

14 1400


1862 = 42 + 420 + 1400

= 7 ( 6 + 60 + 200 )

= 7 ( 266 )

We are subtracting a multiple of 7 from the original number at each stage. If we end up with a result divisible by 7, then the original numbers is, as well. Simple, non?  Now, how do we decide whether a number is divisible by 11?

Fascinating, Monica!

We did not have time for Bill Blunk to make his presentation, entitled How Smooth is Smooth?  Bill will be put at the top of the list for our next meeting, Tuesday 23 November 2004See you there!

Notes prepared by Porter Johnson