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ISPP REMINDER
September
2005
Dear Friends & Colleagues,
In case you haven't
noticed, it's just about that time of year once again. Time to start looking
over the lesson plans, dust off the books and tune up the lecture demo's.
The academic year is almost upon us. Time to start thinking again about new and
interesting ways to get your students excited about physics. But what can you
do? You need resources! You need ideas. Where can you find it all??
ISPP!!
Perhaps you already have the ideas. Perhaps you've attended
a summer workshop. You're excited about it. What now? Share them with ISPP!!
OUR FIRST MEETING OF THE 2005 - 06 SEASON . . . OUR NEXT
MEETING . . .
.
. . is at Morgan Park High School
Wednesday
September
21, 2005
6:30
- 9:00 p.m.
A map and directions are enclosed.
THE FREE GIVEAWAY . . .
. . . something you should find useful to excite student
interest in physics - and who knows? - maybe even your own!
FUTURE MEETINGS. . .
September 21 (Wednesday) Morgan Park High School) -
Roy Coleman
October 11 (Tuesday) Loyola
University, Chicago - Gordon Ramsey
October 28 - 29 ISAAPT -CSAAPT at Riverside-Brookfield High School
December 6 (Tuesday) DePaul University -
Gerry Lietz and John Milton
January 18 (Wednesday) Elmhurst
College - Earl Swallow and Marie Baehr
AT OUR LAST MEETING . . .
Pete Insley (Columbia College) welcomed us to Columbia College and then
being true to his cause, he began the meeting with a phenomenon. He showed us
the interference filter that he had received as a free giveaway at the May ISPP
meeting at Northwestern. He lamented that there had not been enough time at
that meeting to play with the filters, and felt that they were worth a second
look.
When you look through it you see blue and when you
reflect light off of it you see yellow. He displayed the filter on the overhead
projector. When laid flat on the projector stage it appeared blue but as he
rotated the filter lifting one edge off the stage with increasing angle, it
turned purple, red and then orange. Pete had looked at the colors through a
diffraction grating and did not find anything unusual. Then he suggested we
look at the filter through crossed Polaroids. “It will not be what you think.”
he cautioned us. Hmm? A single filter kit is available from
Educational Innovations for $10. Art explained that he got several class sets
with eight filters in each for $70.
Gerry
Lietz (DePaul
University) reminded us about the next ISPP meeting September 21st
at Morgan Park. He asked if there were any new attendees. Jay Coston, Joseph Haberfeld from
Columbia and Krista Sutton newly graduated from Glenbrook North, raised their
hands. Brigid Baier also introduced herself. She is John Baier’s daughter from
Glenbard South High School and will be starting teaching next year. Keith
Dvorkin is new at Downers Grove North High School. Debbie Lojkutz
presented both with New Teacher Bags.
Paul Dolan (Northeastern Illinois University) was browsing through the
local Target store looking for magnets when he discovered the Lighted Whirly.
It had an electric motor that spun a vertical shaft that had three dangling
springy arms. Each arm ended with a flashing light, one red, one blue and one
green. The arms drooped down when the motor was off, but would straighten out
into a flat disk when spun up. Neat!
Paul had found his magnets in a Magnetix kit ($15)
which consisted of a dozen or so iron balls and some magnetized connecting
rods. The rods were plastic with magnets attached at either end. The balls
could be stuck onto the ends of the rods. The balls always were attracted to
the rod ends. The rods could be stuck together but only with the right
polarity.
Several rods could be attached to a single ball. They
could be arranged in structures resembling crystal structures. He showed us
several structures he had assembled. One of the rods was missing a magnet at
one end and Paul thought this might be used to represent a broken bond. He had one of those magnetic marble
which he thought might represent an impurity. The marble was slightly larger
than the balls that came with the kit and distorted the regular pattern.
Paul attached several rods to a single ball all with the
same polarity pointing toward the ball. The interesting thing was that it got
harder to attach more rods with the addition of each rod. As he added the fifth
rod, at first it was repelled until it got really close, and then it linked up.
It reminded us of the strong nuclear force.
Paul had a few giveaways left over from previous meetings.
He had some Bill Conway vectors. These very useful vectors were made out of
bendable soda straws attached to flat magnets using a piece of clay. The arrow
end of the vector was a piece of Styrofoam stuck on the other end of the straw.
He attached the vector to the magnetic black board and demonstrated how the
straw could be oriented in any direction to represent a vector coming out of
the board. Lastly, he gave out a few remaining NASA CD’s on weightlessness.
Thanks, Paul.
Tom Senior (New Trier High School) bought a
night light fixtures that turns on a small light when the room lights go out.
He found it at the Surplus Shed ($1). Tom added a small 3 cm piece of PVC pipe
to shield the photo resistor from ambient light. He pointed the devise at the
ceiling light and it turned off. When he pointed it away from the light it
turned on. He arrange for the light from one nightlight to activate a second
light and then for that light to feed back to the first light activator.
Nothing interesting happened. When he expanded the loop to include three
lights, the lights blinked on and off in succession in a wave that moved around
the loop. Wow! He expanded the circle to include four lights, and again it
remained stable with every other light staying on. A fifth light caused the
array to flash in sequence again. Why did odd numbers flash and an even number
lock into a stable pattern? Tom borrowed it from a friend in Colorado that runs
a Little Shop of Physics.
Pete Insley (Columbia College) passed out plastic bags which contained
several elongated sausage balloons. He blew one up with a hand pump and
released it. It flew off giving a raspberry sound as the air escaped out the
end. Pete explained that while a normal round balloon flitted all over the place,
the shape of the balloon allowed them to go in a more direct path. He would
arrange to have a contest among his students to see whose could go the furthest
down their long corridor. The bags also contained a rubber band and a lesson
sheet describing how he uses them in class. One could improve on the
directionality by slipping the rubber band around the balloon near the nose to
shift the center of mass further from the center of pressure. He suggested that
fins could also be added. He got
50 balloons for $13 at Educational Innovations (the pump came free. He could
get 75 rubber bands for $1.
Gerry Lietz (DePaul University) first showed us his Harald Jensen box.
It looked like an ordinary large cardboard box. Gerry explained that the bottom
was reinforced with a piece of plywood and the top flaps folded around a second
piece that had straps and a handle. The straps wrapped around the box firmly
attaching the handle to the box for easy hauling around of equipment for a
demonstration. Then he showed us a
Dilbert cartoon in which Dilbert’s boss addresses an apparently idle worker
leaning against a wall with the trite repartee “What are you doing? Holding up
the wall?” The worker departs as
the boss relishes the moment. Then the wall falls on top of the boss flattening
him. Dilbert identifies the worker as the new structural engineer who
apparently was indeed holding up the wall. Hmm.
Gerry held up a card that had red, yellow, black and white
portions. He turned the room lights off and illuminated the card with yellow
light. We saw the colors muted but still recognizable. Then he moved over to a
second yellow light in which the reds appeared gray and the yellows appeared
white.
Gerry drew a spectral intensity plot as a function of
wavelength for the incandescent light passing through the yellow filter. It
transmitted light from the green through the red. Gerry explained that though
green and red light was transmitted, it appeared yellow. The second light was a
Sodium light which had only a narrow band of yellow light in its spectrum. When
the card was viewed in the Sodium light there was no red for the red color to
reflect, so it appeared grey. The yellow and white portions of the card both
reflected yellow and so both appeared yellow.
John Milton (DePaul University) recalled the radon experiment that Art
Schmidt had shown using a balloon. John explained that he would inflate an
ordinary balloon and charge it up using a rabbit fur. Then he would wait for a
half hour and then deflate the balloon and place it in front of a Geiger
counter and observe a count rate significantly higher than background. The
charged balloon collected the products of radioactive radon from out of the air
in the room. John did some searching on the web and found that he could also
use a Styrofoam cup. John rubbed the cup with fur and placed it on a Vernier
student radiation monitor. The activity did not seem to collect. Fortunately,
John had some data from a previous run. John mentioned that this experiment
lends itself well to a high school venue since inexpensive detectors are
available through Vernier. Although radiation sources might shunned in a high
school lab, Radon is everywhere.
John had read in the literature that the prominent
activities are from decay products of 222Ra among which are 214 Pb and 214 Bi
with 27 and 20 minute half lives
respectively. He also read in an article from the January 1992 The Physics
Teacher that a ball collected a considerable amount of radon activity after a
vigorous 4 hour game of handball with 43.9 minute half-life. Some reported a 55
min half-life using the Styrofoam cup.
John took 30 sec counts for 300 minutes. With the balloon he
got an effective half life of 45 minutes. Using a Styrofoam cup with 5 minute
counts he obtained a half-life of 55 minutes. John passed out a handout with
references.
Art Schmidt reported that his students do the experiment
with a Sodium Iodide detector and software that can take complete spectra at timed
intervals. They can then look at the half-lives of individual photo peaks in
the spectra to obtain pure half-lives of the Pb and Bi isotopes. He promised to
bring spectra to the next meeting. Art suggested that the obvious advantage of
the balloon is to present a large collection surface which can be then further
concentrated by deflating the balloon. He recommended that rather than popping
the balloon one should gently deflate the balloon by making a hole in the neck
of the balloon where there is less tension. He also mentioned that the dust
accumulated on the typical CRT monitor screen is not radioactive, basically
because the radioactivity has decayed away since the dust was deposited.
Stewart Brekke (Chicago Public School Teacher retired) reprised his
presentation at the Northwestern meeting. He used a meter stick pressed against
the top of a desk with half of the stick extending over the edge of the desk.
He taped a marker to the end of the stick and vibrated the end while moving a
card over the marker to record the vibration. He passed out a copy of the The
Physics Teacher article from the String and Sticky Tape Experiments feature
from February 1987 which he authored. The article described the demonstration.
Art
Schmidt
(Northwestern University) had recently purchased a cold heat soldering gun. The
tip is a very light graphite material that has a very low heat capacity so it
heats up fast and cools down fast as well. In typical soldering iron heat is
generated with a current passing through a resistive material. The heat is
conducted to the tip which is usually a good conducting metal. This gun has a
tip that consists of two pieces side side by side with a gap between. The
electricity to heat the tip flows down one end and back the other using the solder
to complete the circuit. As soon as you lift the gun from the work, the
connection is broken and the gun cools down rapidly due to the low heat
capacity of the tip material. Art thought that this high tech gun would be a
good stimulus for discussion of topics in heat.
Laura Nickerson (Illinois Math and Science Academy)
talked about the great resource available on line http://www.esa.int/esaSC/index.html
European Space Agency that has a mandate to do outreach. If you sign up you can
get free stuff. She received a DVD on stellar evolution using pictures from the
Hubble Space Telescope.
Then Laura
showed us a glass cylinder filled with water. Sealed in the cylinder with the
water was an hourglass half filled with blue sand. She noted that the hourglass
floated in the water. She upended the cylinder which also inverted the
hourglass within. The sand poured into the bottom of the hourglass while the
hourglass slowly ascended. Laura explained that there always was a bubble
underneath the hourglass buoying it up. The flow of water around the hourglass
as it rose kept the air bubble from moving up above the glass until it reached
the top. Laura said that you can change the rate that the hourglass ascends by
changing the size of the air bubble trapped under the hourglass. You can get a
cheap one from American Science and Surplus at $12 but she was not impressed
with the quality.
We recalled
a similar apparatus which was puzzle in which when inverted the hourglass would
remain on the bottom for a time and then mysteriously begin to rise. The
explanation was that while the sand remained in the upper part of the hourglass
it was top-heavy and jammed against the sides of the column keeping it from
rising until enough sand had moved to the bottom at which time it would align
itself in the column and begin to rise in the column.
Earl Zwicker (IIT) handed out balloons and asked
us to put a nickel or a quarter through the neck into the balloon and blow up
the balloon and then tie it off. The he told us he was going to rotate the
balloon in a circular motion and ask what we thought would happen. Some of us
recalled that the coin would roll around on the inside of the balloon. Earl
blew up his balloon and gave it a twirl. What made the coin stand on end and
roll around on the inside? Some one recalled the circus performance where a
motorcycle was driven around inside a wire mesh ball. Earl suggested using
several coins in the same balloon.
Bill
Shanks (Joliet)
told us that an effective presentation should always include a story. He began
by telling us about how when he was a kid he saw someone jump off a hayloft in
a tall barn three stories up into a pile of hay without getting hurt. This
accompanied his discussion about impulse. The pile of hay drew out the time it
took to arrest his motion of fall. On another occasion he told us about a
property line dispute which he was able to resolve to his satisfaction by
locating the surveyor’s markers at the four corners of his lot. Several of the
locations were easily found using a magnetic compass to locate the iron pin
which became magnetic over the years in the earth’s field. Several pins had
been buried in several inches below the surface. A tree had grown over the
obvious place of the fourth marker. The tree had been cut down and with a
little work he managed to find the last pin within the wood of the stump of the
tree. Then he wanted use his compass to lay out his property line. He realized
that because he couldn’t read the compass to better than 2 degrees. He could be
off by six feet by the time he covered the length of his property.
Lastly he wanted to put up some shelves above his
range and need to locate the studs behind the dry wall and couldn’t find his
stud-finder. He decided to use his compass but found that the metal range was
affecting his compass readings, due the range being magnetized in the earth’s
field. Near the top of the range the compass pointed in toward the range. On
the bottom it pointed away from the range. He decided to look at his
refrigerator and found a similar magnetization . But he also observed some
strange anomalies which he realized were due to the refrigerator magnets on the
door.
Eileen Wild (Retired) thought we’d enjoy a cartoon she read in the
Chicago Tribune. Fox Trot has a history of using math and physics references.
In this one Paige is asked what time she went to bed and responds with
√121. Jason asks her what’s
on TV and she says 4!. For the
temperature outside she tells her brother “sin-11”. And when her dad
asked her what she bought, she exclaimed that she got Sk=1¥ 1/3k. In the last panel her mother is musing
that perhaps Paige has over-studied for her math exam. Paige then asks for a piece
of 1.3416.. for snack. Have you figured them out yet?
Jim Szeszol () pulled out a few clear glass
bottles and blew across the top of each showing us how the frequency gets lower
with an increase of bottle size. He showed how with a slide whistle he could
lower the frequency by lengthening the tube. He could get a higher pitch at the
same length by over-blowing to excite a higher harmonic. He then showed us a
piezio electric buzzer he attached to a rod. A battery at the other end of the
rod powered the buzzer at a single high-pitched frequency. Jim learned of this
demo from Janet Landato. Jim lowered the speaker into a graduate cylinder and
we heard the sound intensity increase and decrease as he passed through
successive resonance points where the effective length of the tube from the
speaker to the bottom was close to a multiple of a half wavelength plus a
quarter wavelength. Jim measured about 8.7 cm between three resonances (each
resonance separated by a half wavelength) and using a speed of sound of 345 m/s
obtained a value for the frequency of 3960 Hz. The package label gave a
frequency of 3500 Hz.
Pete Insley also had another several give-aways,
electronic stencils and 12-volt transformers.
Then it was
time for the annual John Rush Award. Bill Blunk (Niles West High School) explained
the history of the award. The John Rush award is given to one of our members
for exciting ideas and 'phun' contributions to the group. John taught for many
years at Eisenhower High School in Blue Island, and coined the word
'pneumenon', a new phenomena that you haven't experienced. On the first
day of class John would show his students a strange contraption and challenged
them to discover what it was. Then Debbie
Lojkutz announced this year's winner. Nate Unterman (Glenbrook
North High School) came
up to receive the award and clamped the 'pneumenon' to the table to peel the
traditional apple.
Submitted
by Arthur 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
BRING FRIENDS BRING
IDEAS ! ! SEE
YOU THERE ! ! !
Roy Coleman Gerry
Lietz Ann
Brandon
Tom Senior Earl
Swallow Paul
Dolan
Jim McConville Ruth
Goehmann Mike
Kash
Jan Dudzic David
White Tung
Jeong
Art Schmidt Chris
Chiaverina Kevin
McCarron
Pete Insley Earl
Zwicker
. . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . .
During 2005 - 06
Coordinators: Paul
Dolan
Gerry
Lietz
Earl
Zwicker
ISPP Authors: Gerry
Lietz Data
Base Managers: Roy
Coleman
Art
Schmidt Earl
Zwicker
John
Milton
Pete
Insley
Photographers: Paul
Dolan Treasurers: Ann
Brandon
Art
Schmidt Peter
Insley
Gerry
Lietz
John
Milton
Earl
Zwicker
Special Events Committee:
Physics Day - Ann Brandon, Roy Coleman, (Co-Chairs)
John Rush Award - Nate Unterman (chair), Eileen Wild, Debbie Lojkutz, Bill Blunk (ex-officio)
Harald Jensen Award - Keith Bellof
(chair), Martha Lietz, Ann Brandon
Annual Tri - Physics Meeting -
Bruce Illingworth, Gerry Lietz
National Bridge Building
Committee - Carlo Segre
New Member Committee – Kevin McCarron
(coordinator), Ann Brandon, Pete Insley, John Milton
