ISPP REMINDER
January 2006
HAPPY NEW YEAR ! !
OUR NEXT MEETING. . .
the Annual Tri Physics Meeting: ISPP, Physics West and Physics Northwest
. . . is at Elmhurst College
Wednesday
January 18
NOTE TIME -------- 5:30 - 9:00 p.m.
5:30 for Pizza before the regular meeting at 6:30. A map and directions are enclosed.
THE FREE GIVEAWAY . . .
. . . is always a neat thing at Elmhurst, thanks to the ingenuity of Earl Swallow and Marie Baer our hosts there! Can you guess what it will be?
FUTURE MEETINGS. . .
January 18 (Wednesday) Elmhurst College - Earl Swallow
February 16 (Thursday) Northeastern Illinois University - Paul Dolan/Joe Hermanek
Mar 8 (Wednesday) Joliet West High School - Debbie Lojkutz/Erik Jergens
Apr 4 (Tuesday) Lake Forest College - Mike Kash/Bailey Donnally
May 8 (Monday) Northwestern University - Art Schmidt
June 5 or 12 (tentative) Columbia College or Museum of Science and Industry
THE 32nd CHICAGO REGIONAL BRIDGE BUILDING CONTESTS...
...will be held on... February 7, 2006 Tuesday at IIT.
ALL information is available at http://www.iit.edu/~hsbridge, including where, how, when to get your bridge kits.
Contact Phyllis or Cathy at (312) 567-3025, IIT, to buy kits. But at the Web site you will find the Rules and all other details.
NOW is the time to get your students involved. Ask any colleagues you may meet at ISPP, Physics Northwest, Physics West meetings, and they will be happy to tell you about its value to motivate student interest, and to help you get started!
Prof. John Kallend at IIT is the contest coordinator. Contact him at kallend@iit.edu if you have questions.
Don't miss the fun! It gets better every year!
OTHER MEETINGS . . .
CSAAPT Saturday April 1, Chicago State University - Mel Sabella/Sam Bowen
ISAAPT Fri – Sat. April 7 – 8 Illinois Central College, East Peoria
AT OUR LAST MEETING. . . .
Gerry
Lietz
(DePaul
University) opened the meeting with an oldie demonstration which
happened to
appear in Tom Green’s ‘From Our File’ column in the December 2005 issue
of The
Physics Teacher. He showed us a contraption that consisted of two
bicycle
wheels 
mounted on
a common axle. He suspended the pair of wheels from an attachment point
on the
axle midway between the wheels using a cable to the ceiling. He spun up
one
wheel and then, in true ISPP fashion, asked us to predict what would
happen
when he suspended a mass from one axel end. He tried several other
arrangements; more mass, different positions. He spun up the second
wheel in
the same direction as the first and added the mass to the end of the
axle. In
most cases we could see a precession as a result of the odd mass
hanging on the
axel. When he put the weight on the opposite side the wheel precessed
in the
opposite direction.
Then Gerry spun up both wheels in the opposite direction and asked what would happen when he hung a weight on the end of the axle. The wheels tilted down as if they were not spinning at all. The opposing angular momenta of each wheel cancelled each other out. Gerry moved the pair of wheels around to show that there was no strange reaction as occurred when the wheels had any appreciable angular momentum. Gerry passed out copies of the TPT article.
Our own Earl Zwicker had authored the original TPT column ‘Doing Physics’. A then younger Tony Behof (DePaul University) appeared in the picture accompanying the article. The Aluminum axles were a free giveaway at a DePaul ISPP. Gerry first saw this demonstration by Walt Connolly at Appalachian State at the summer AAPT meeting in 1974.
John Milton (DePaul University) praised the low friction of the new a Pasco turntable with a stool mounted on it. He measured a moment of inertia. He spun up a wheel and held the axle vertical. He then inverted the wheel which caused him to rotate in the opposite direction. He explained how conservation of angular momentum causes the reaction. Then John used the wheel pair spun in opposite directions and we could see that there was no effect.
Roy Coleman liked to give his students a spinning weighted wheel to hold out from one end. They get an unexpected result as they tried to move the wheel. Roy also remembers an old 8mm film involving a suitcase in which a gyro was placed. It also gave some unexpected results to anyone trying to move the suitcase.
Gordon Ramsey (Loyola University) announced three part time teaching opportunities for the fall. Contact the department chair Asim Gangopadhyaya at agangopa@luc.edu. Roy Coleman (Morgan Park High School) also has an opening for a Physics teacher and possibly Chemistry. Roy noted that he had received a letter from Ian McKenna all the way from Scotland. Nate Unterman (Glenbrook North High School) introduced Bob Froehlich who is student teaching under him and brought our attention to a new toy with Pirate Ship Park by K-nex.
We then had all the new teachers introduced themselves. Kathleen Grimes teaches physics at the Young Women’s Leadership Charter School. Stephen Philip is at King College Prep High School. Eric Miller is at Resurrection High School. Erick Jurgens is working with Debby Lojkutz at Joliet West High School. Amy Meyers is at Lockport Township East High School.
John Milton continued the
meeting by
showing us a special yoyo he found at the Oriental Trading Company. The
yoyo
lights up when it spins. John took the yoyo apart to see how it worked.
Inside
was a centripetal switch that connected an LED to a button battery when
the
yoyo spun. Another mechanism seemed to operate as a clutch to release
the axle
when the yoyo spun allowing it to automatically free w heel at the end
of the
string. This duplicated the action of a traditional yoyo to stick at
the bottom
of its travel or “sleep” on a loop in the string. Gerry noted that the
string
on this yoyo was tied with a slipknot that tightened on the axle not
allowing
for this classic maneuver. The clutch would allow this yoyo supposedly
to do
this tricky trick easier. The yoyo was modeled after a fancy chrome
automobile
wheel sans tire. It even had the extra free wheeling spinner that you
might
have seen on fancy hubcaps, which give the illusion that the wheel is
turning
when the car is stationary. John passed out a handout that provided
several
links. One was for the Duncan Yoyo Company, which provides a lesson
plan and
free yoyos to a class www.yo-yo.com/teachers_section/teach_lesson_yoyo.html.
Great resource!
Bill Blunk (Joliet Central High
School (retired)) had spent the summer
putting a roof on his cabin in Montana and came away with a few
interesting
pieces of info which he shared in a handout. Two common roof pitches
are
designated as 4/12 and 6/12 the ratio of their rise to run. Their
respective
pitch angles are 18o and 27 o. In order not to
yield to
the gravitational force and slide down off the roof one must have a
coefficient
of friction greater than the tangent of the angle, or 0.33 and 0.50
respectively. Bill speculated that if he were laying down a plywood
roof
substructure and had sawdust afoot, according to the CRC handbook that
gives
the coefficient for wet wood on wet wood as 0.2, he would be just a
little shy
of what is needed. Watch your step!
If that weren’t incentive enough to inspire students to study friction, Bill found a neat toy in such an unsuspecting place as the Great Falls Montana equipment store. He unwrapped a package marked Fun Slides Carpet Skates ($16.95 @ www.funslides.com). The toy is an apparent application the same technology used for Easy Move carpet movers. Bill unrolled a carpet and asked Eric Jurgens (Joliet West High School) to don the skates. They simply strapped on over his street shoes. Bill used a spring scale to measure the force need to keep Eric moving at a constant speed. Having determined Eric’s weight, he determined the coefficient to be 0.17 which would mean that he would slip on a mere ten-degree slope. Bill placed the carpet on a plywood board that he shimmed up to make a 10o incline and recalling that he measured the coefficient of kinetic friction, he had Eric stand on the incline and gave him a slight push. Eric slipped easily down the slide. Neat! Bill mentioned that you could also get a carpet hockey puck but that the site suggested using regular hockey sticks. Bill balked at that suggestion as an appropriate activity for his living room.
Bill related how he had a long time Montana neighbor Richard Schwab a retired professor from Cal-Davis happened to mention recently that he attended Harvard and roomed with Tom Lehrer. He pointed us to a web site www.physicssongs.org and asked to clicking on the Physical Review which was a show apparently put on in the Harvard physics department in 1952-53 and included a collection of hilarious satirical physics related songs written by Tom Lehrer. He played us one of the songs “S is ½ g2 “. According to Bill the song was recorded on a wire recorder. It will be eerie as you read on how many times the equation of this title was referenced through the rest of the evening. It was not planned.
Art
Schmidt
(Northwestern
University) set up a
Gauss rifle (see info on web site www.scitoys.com/scitoys/scitoys/magnets/gauss.html
that consisted of a cube magnet attached with a ‘C’ clamp to a
horizontal rail
with north and south poles aligned horizontally along the rail. Two
nickel
balls were placed adjacent to the one end of the magnet and a third
ball was
allowed to roll into the empty end of the magnet. The resulting
collision fired
the end ball on the opposite side away at a surprisingly large speed.
By
lining up several units in succession one can increase the speed of the
ball
coming off the last stage. Art fired the mechanism horizontally from
slightly
above the surface of the table and, noting the time of drop to be given
by s =
1/2gt2 , the horizontal distance the ball traveled before
hitting
the table was a good indicator of how fast the ball left the apparatus.
He then
added a second stage and we saw that the ball traveled further and
therefore
faster than with just one stage. Several of Art’s students had put
together a
five-stage rifle from instructions on the web. It is an interesting
example of
energy stored in a magnetic field. It was new phenomena for most of us.
Pete Insley (Columbia College) passed out dropper poppers for everyone. They are available for $1.50 at Educational Innovations. Pete uses them in discussing potential and kinetic energy. These familiar rubber ball halves, when inverted and laid on a solid surface, spontaneously jump up to a surprising height. Pete found that if you place a loaded popper on the end of your finger it seems to go twice as high.
Roy Coleman (Morgan Park High School
(retired)) showed us his t-shirt
that had the names of colors printed in colors. The names did not
necessarily
correspond to the print color. It was a brainteaser challenge to try to
name
the color rather than read the color. He also had a t-shirt from an
APPT
meeting which read, “Don’t drink and derive.” The AAPT has t-shirts
with
several other clever science related titles at www.aapt.org/Store/products.cfm.
Roy had also found a KB Toy’s Darth Vader potato head.
Tom Senior (New Trier High School set up a conical pendulum he fabricated from an electric powered propeller driven airplane for which he had removed the main wing. You can choose from several models at www.physicstoolboxinc.com. Check it out for other neat stuff as well. Tom added a mass to the body of the plane and asked if the plane would go faster or slower as a result. It didn’t seem to make a noticeable difference.
Tom’s latest
version is,
amazingly enough, made from
a Dollar Store personal electric fan. He simple added a vertical tail
fin and
reversed the blades and batteries. He wrapped a rubber band around the
case to
attach a paper clip. The tether is attached to a central support using
a
‘fender washer’ as a bearing. He drilled a small hole in the washer to
attach
the tether. He then mounted the washer to the end of a wood dowel with
a screw
through the central hole of the washer. He stuffed the wood dowel into
the end
of a hollow steel vertical support rod. You can’t get much cheaper than
this.
Elegant! Note that Tom uses a paper clipper (black spring steel clip)
attached
to the pole to spot the vertical height of the flyer.
Martha Lietz (Nile West High School) had been collecting physics related comics that student bring her. Over Thanksgiving she scanned some 200 cartoons in and arranged them in topic categories. She showed us her favorites. A zebra running toward the edge of a cliff puts on the breaks in a cloud of dust. As the dust settles we see the zebra with all his stripes pushed to the front. In another an astronaut on a space walk takes break to crack a brew and suffers the reaction opening a pressurized beer can in space. a popular cartoon witch finds a switch labeled gravity and switches it off. She had made copies of her collection to pass out. Having some extra room on the CD she also included some funny video clips. Thanks.
Eileen
Wild
(retired) also showed us
her latest favorite cartoons. In
one the non-smoking area of a dinner is mysteriously devoid of the
smoke that
fills the rest of the area. The caption read, “Physics as understood by
restaurateurs. A Foxtrot cartoon Jason has relabeled the constellations
with
names from their computer games. She thought how apt for children to
make
things relevant.
Nate Unterman (Glenbrook North High School) over the summer working in the Material Science Center at Northwestern University had developed a LEGO model of an Atomic Force Microscope. The key part is a cantilever arm which ends in a probe ‘needle’ that is passed over various sample surfaces. The vertical position of the arm is noted and recorded by the deflection of a laser pointer beam off a reflecting surface attached to the arm. Data is entered into a spreadsheet program that takes the deflection and displays it on a surface plot in three dimensions. Features of the sample surface can be reproduced in the graph in an analogous way that the AFM functions to image atomic surfaces. Nate suggested that the surface-plotting feature of the spreadsheet could be useful in visualizing fields in other situations such as the experiment in which an electric potential of a region with an electric field is explored with a voltmeter.
Bob Froehlich (Glenbrook North High School) designed and cut out a friction block from a 2 x 6 piece of lumber ten inches long. He cut slices off the edge and glued two of them to one of the sides like runners on a sled, giving the students two different surfaces areas to test. He passed out instructions.
John Baier (Glenbar South High School) set up a ball-launching ramp (available at most science catalog for $20) with a support at the bottom that held a second ball. The support could be adjusted so that when the ball came down the ramp it just grazed the second ball enough to make it fall off the support nearly vertically while the first ball continued in a trajectory that carried it horizontally quite a distance. Both balls hit the ground at the same time as evidenced by the single click we heard as they hit the floor.
Then John showed us a second experiment he did with the ramp involving a collision. He used a plumb bob to mark a point on the floor directly below the bottom end of the ramp. He started by running the ball, he called ball A, a steel ball, down the ramp with no collision and marked where the ball landed on the floor with respect to end of the ramp. He did this by placing a piece of paper covered with a piece of carbon paper copy side down. The impact of the ball left a carbon mark on the paper below. The distance the ball traveled horizontally indicated the initial speed of ball A before the collision. (How many times have we used principle tonight?) Then he placed the second steel ball, ball B on the support such that the first ball would hit it with a angle that would carry off to one side while ball A caromed off angling off in the opposite direction, both also having a forward motion. John ran the balls in collision mode several times and marked their resulting landing locations. He repeated the experiment using a marble for ball B.
John pulled up the paper and taped it to the blackboard and drew a straight line from the plumb mark to where the ball A landed without colliding and a line to where ball a landed when it had collided with ball B, and a third line from the plumb to where ball B impacted at some 45o angle with respect to the first line. He measured the length of all three lines and showed that the length of the angled paths, sides of a right angle calculated to be equivalent to the measured hypotenuse, undeflected velocity. Since both balls had the same velocity this was equivalent of verifying the conservation of the momentum of the collision in a graphic analysis.
John showed that the velocities did not work out the same for the marble, but noted that the marble had a mass of a third of the steel ball. When considering this it did work. John could make he collisions non-elastic by adding a loop of masking tape to ball B. He handed out a sheet describing the exercise. That’s getting quite a bit out of a simple set-up.
John Milton (DePaul University) called our attention to a web sight authored by Bob Morse www.tufts.edu/as/wright_center/fellows/bob_morse_04/. In it Bob points out that next year marks the 300th anniversary of the birth of Benjamin Franklin. He has collected a series of experiments that were originally done by Ben written in his own words that the visitor is encouraged to perform with Ben as their lab partner. He also has a collection of short film clips. In one he describes how to make a film clip Leyden jar. Simple wrap the outside of the bottom of the canister with Aluminum foil. Poke a half uncoiled paperclip through the top. Fill the canister with enough water to touch the bottom of the clip when the canister is closed and there you have it! Beware; it has quite a capacity for charge. John had made one for us to see and charged it up with a plastic rod rubbed with fur. He then was able to make a fluorescent light flicker with the discharge. He passed a charged canister around and we felt a good shock discharging it with our fingers. Our free give-away for tonight was a package containing all the parts need to make our own film canister Leyden jar. Thanks John and Gerry for sponsoring tonight’s meeting.
Submitted by
Art Schmidt
For any information regarding ISPP contact Gerry Lietz at DePaul University, Physics Department, 2219 N. Kenmore Chi. IL 60614 phone: 773-325-7333 e-mail glietz@depaul.edu. ISPP home page: http://condor.depaul.edu/~glietz/ispp/ispp.html
DIRECTIONS TO ELMHURST COLLEGE
By way of Interstate 290 (Eisenhower Expressway)
Exit at St. Charles Road, just west of I-294
Travel West on St. Charles, past York Road, to Prospect Avenue
Turn right onto Prospect for two long blocks, past the front of the campus on your left, to Alexander Boulevard
Turn left, then left again, into the main parking lot
By way of Interstate 294 (Tri-State Toll way)
From the south, exit at I-290
From the north, exit at I-290 West, then exit again immediately at Illinois Route 64 West (North Avenue)
Follow North Avenue about a half-mile, past York Road, to Maple Avenue
Turn left. Follow Maple Avenue another half-mile, two blocks past railroad tracks to Alexander Boulevard. (Maple Avenue becomes Prospect Avenue after the tracks)
Turn right, then left, into the main parking lot
By way of Interstate 88 (East-West Toll way)
Exit at York Road, just west of I-294. (Take ramp marked I-294 South)
Travel north on York for about two-and-a-half miles to St. Charles Road
Turn left on St. Charles to Prospect Avenue
Turn right on Prospect for two long blocks, past the front of the campus to your left, to Alexander Boulevard
Turn left, then left again, into the main parking lot
Meet Here
