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1997-2006 Academic Years Teaching Equipment |
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1997-2006 Academic Years Teaching Equipment |
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16 September 1997: Ann Brandon [Joliet West HS]
demonstrated the use of the Trundle Wheel to measure distances,
and she tried it out on the carpet in 118 SH. She laid out a distance
of 2 meters with meter sticks. When she went North, the
distance read 1.985 m, whereas going South it read 2.010 m.
Similarly, going East she obtained 2.02 m, versus 1.985 m going
West. How come?
The answer seems to relate to an asymmetry in the nap of the carpet. As a test, the distance going SouthEast was 2.01 m, whereas going NorthWest it was 1.99 m [I think!]. Verrrry interesting!!
30 September 1997: First, some important information on obtaining science materials.
13 October 1998: Bill Shanks [Joliet Central HS, retired]
Walmart [or, more precisely, Sam's Club, for members only] has a
laser for $15.00. Bill suggested that we prepare a "laundry list" of
experiments one could do with a laser, such as looking into an ice
cube, looking into a light bulb, reflecting off the gradations on a
ruler to see fringes, etc.
13 October 1998: Betty Roombos [Gordon Technical HS]
She is fortunate to have a student who has a digital Camera, and showed
pictures of physics activities taken by the digital Camera, and printed
on her color printer. It was impressive how well they looked while
printed by a Hewlett-Packard 722C ink-jet printer, and on regular
paper.
27 October 1998: Bill Blunk [Joliet Central HS]
Pasco is once again stocking the air rocket.
$24 for the complete set (Pump-Projectile-Washer)
$11 for the body only
1-800-367-6695
He showed a device and asked us what it was. It was a noise maker in 3 pieces, called a Statue noise maker. It is sold in 3 parts to make transportation and storage simpler. It is available at K-Mart for $4.95. A warning is included to not use it closer than 1 ft to one's ears. [But then, how could one possibly blow into it to make the sound?? Perhaps it is OK, because the sound goes away from the user.]
***Comment by Porter Johnson:
One should make every effort not confuse this word with the Greek word noumenon,
which is used Kantian philosophy as an object understood by
intellectual intuition, without the aid of senses [http://www.britannica.com/eb/article?eu=57768],
as opposed to a phenomenon, which is a fact, circumstance, or
experience that is apparent to senses and that can be scientifically
described or appraised. It is important to be mindful of these
distinctions, in case there are any philosophers "on the loose".
10 November 1998: Bill Blunk [Joliet Central HS]
He brought in the address of his favorite Science Store. (Should we
have a SMILE field trip??)
10 November 1998: Carol Zimmerman [Lane Tech HS]
commented that she has 6 older computers set up with Vernier
Science and Technology [http://www.vernier.com/]
programs so that the students can graph items (6 computers and 3
printers)
He showed some magnetic stick figures that may be obtained through Hearth Song Corporation: 1-800-325-2502 or 412-613-0371. Web address is: http://www.hearthsong.com/.
Another comment referred to the PAPER-RIVER talked about earlier using Stomper cars to traverse a moving roll of paper (river). Reference to Dave Drymiller of using a dot-matrix printer to pull the paper at a constant velocity (with a series of computer-generated Line Feeds).
02 February 1999: Bill Shanks [Joliet Central HS, retired]
He bought a Metronome [
http://ofcn.org/cyber.serv/academy/ace/sci/cecsci/cecsci171.html]
and found a use for it. One plan for use was to judge the speed of a
car passed, or passing. First take a starting point and getting a
timing of each up to a fixed point. [2 sec for the faster car; 3 sec
for the slower car] The ratio is 3/2, and if the slower car is
traveling at 60 MPH thus the faster car was traveling at 90 MPH
16 March 1999: Betty Roombos [Gordon Tech HS]
She had recently received the PASCO [http://www.pasco.com]
motion sensor, sill like the polaroid camera focus sensor?? This is
greatly better than the previous one. This has a greater range, and
ability to capture the distance. She showed graphical motion of a "push
and go" child's toy. The push and go was for totters and is quite
sturdy. Exhibits a fairly even acceleration. It seems to be a good
addition the store room.
20 April 1999: A Tobecksen [Richard Vocational High School]
He brought in Cuisinaire "Pattern Block Puzzles" [http://www.etacuisenaire.com]
by having groups work together solving them. The problem utilizes
cooperative Learning.
The problem is to take blocks of various shapes and colors and make a specified figure.
02 May 2000: Bill Blunk (Joliet Central HS)
showed us a physics "toy" called a ROMP [Randomly Oscillating
Magnetic Pendulum], which came from Edmund Scientific. It is
item CR82-172, available for $13.95. See the website http://www.scientificsonline.com/.
(It is also
available at American Science Center. See the website http://sciplus.com/.) It has a flat
metal base about 8 in square. A pendulum with a length of about 12
inches is suspended above the base so that, when at rest, its end is
about 1 inch above the center of the base. The pendulum is made from a
rigid, slender plastic rod, and it has a disk-shaped magnet (about 1
cm diameter) at its end. There are 9 identical disk magnets stuck
to the base by magnetic attraction; they can be arranged on the base in
any pattern one desires. Bill placed them in two concentric
circles with one at the center. When he held the pendulum out at an
angle and released it, it swung in an erratic pattern over the magnets
on the base. He used it as a model for nuclear forces. The magnet on
the end of the pendulum he likened to a neutron, and the other magnets
on the base represented particles in the nucleus. When he held the
pendulum at a high angle to represent a neutron with high energy, the
pendulum swung in its erratic pattern. But when he lowered the angle to
represent a neutron with smaller energy, the "neutron" magnet became
"captured", and centered itself over the magnet at the center of the
base. Neat!
12 September 2000 Ann Brandon (Joliet West HS)
held up a bunch of AAPT Product
Catalogs, 1999-2000 edition, and gave them away to us, reading to
us some of the useful things that were available. Ann also invited us
to get our students involved in the Physics 2000 Photo Contest,
and showed us one of last year's winners, a photo of a Coke Can
balancing on edge. And we also received an ISAAPT Flyer. Thanks,
Ann!
24 October 2000 John Bozovsky (Bowen HS)
asked us if anyone knows where to get replacement parts for a Pasco
air track setup. Where can they be found. No one seemed to know,
although there were suggestions. Porter Johnson suggested using
Pasco's websites http://www.pasco.com/
and http://www.pasco.com/products/.
John responded that he had actually talked to them on the phone,
without success. Maybe we'll find out next time!
05 December 2000 Rich Goberville (Joliet Central HS)
showed us a bunch of physics "toys," that can be used to teach/learn.
First was a colorful ball. He recalled the experiment in which the
teacher throws a ball straight up and asks the class questions about
its motion, such as: a) At the instant the ball loses contact with my
hand, is its velocity positive, negative or zero? - Most students get
this one correct and answer positive, since up is chosen as the
positive vertical (+y) direction. b) Is the acceleration positive,
negative or zero? - Most students answer that the acceleration is
negative, since gravity acts downward in the negative vertical
direction (-y). c) At the instant the ball reaches its highest point,
is its velocity positive, negative or zero? - All students get this
correct with the answer, zero. d) Is the acceleration positive,
negative or zero? - More than half the students will say acceleration
is zero!. Aha! They are mistaken, of course, since acceleration due to
gravity is always downward and therefore negative; gravity does not
turn off at the top! Now - Rich throws the ball up so it
strikes the ceiling. But it sticks there for about a second! - then it
falls down! "That is how it would look if the acceleration became zero
when the ball reached its maximum altitude!" Rich tells them.
Beautiful!
He showed us the novel behavior of the "sticky" ball a few more times. What a great way to make that point!
Rich then told us how, when he was younger, he pushed against a large (about 2 ft diameter) pipe to start it rolling downhill toward a creek where his younger brother waited to "catch" it. As it gained speed and neared his brother, Rich suddenly had an intuitive insight about what might happen to his brother - though he hadn't learned the word "inertia" yet - but before he could warn his brother, the pipe hit him! (He was hurt and suffered broken fingers - otherwise ok.) But Rich remembers his first intuition for inertia as developing from this incident.
He showed us a Chinese Yo-yo; then a Gyro-Frisbee (helicopter) launched by pulling a plastic stick that operated gears to spin its blades to high speed; a Balloon-Copter that was caused to spin by air from an inflated, attached balloon pushing out through jets at the ends of its blades; and a Balancing Bird! Then he handed out a smaller version of the bird, so we each got one. Available at low cost for a quantity. All these items came from this source:
Oriental TradingThey will send a catalog on request.
4206 S 108th St
Omaha NE 68137-1215
1 - 800 - 875-8480
http://www.orientaltrading.com/
Rich told us another story in which he got his brother to hold on to what amounted to a freely rotating gate. Rich managed to get it spinning fast enough that his brother's legs stretched out almost straight behind him - before he lost his grip and received a broken arm! Being Rich's brother wasn't easy! This was a lesson on centripetal and centrifugal force that he remembers. He then showed us a colorful sphere about 4 inches in diameter. When he held it up and made it spin by pulling a plastic strip. many colored (diode?) lights lit up inside, which was quite pretty to see. As the spin wore down, the lights gradually winked out. What made it work that way? An example of radial forces at work again?
Finally, he showed us a Skyliner. It was in the shape of an inverted L about a foot long, and he held it by its vertical portion as a handle. When he made its horizontal radius spin about its vertical axis, the end of its radius spelled out in glowing red the word PHYSICS in a circular band that appeared to be suspended in space. LEDs were being turned on-and-off in rapid sequence and persistence of vision resulted in the illusion. Available from http://www.theskyliner.com/ It may be programmed to spell out a wide variety of messages. What a great set of ideas! Thanks, Rich!
25 September 2001 Earnest Garrison (Robeson HS)
passed around a vehicle that had been made out of the following basic
ingredients:
The device worked up very well; he wound up the rubber band, which drove the propeller about its {paper clip} shaft and caused the vehicle to travel across the table. The following variations were suggested
Very interesting, and very cheap, Earnie!
11 December 2001: Arlyn van Ek (Iliana Christian HS,
Physics): Loc Liner
Arlyn, like many of us, had bought a miniature video camera from
All Electronics Corporation [http://www.allelectronics.com/]
during the past year. This camera is particularly useful for showing
small objects/experiments on a large screen TV for all the class to
see, but it is always difficult to hold the camera in just the right
place to get an image for students to see. Arlyn showed
us how he solved this problem. He mounted the video cam in a
manner similar ot a light bulb on a goose neck lamp. He made the
flexible "gooseneck" part from plastic piece called Loc Liner,
obtained from
Lockwood Products Inc
5615 SW Willow Lane, Lake Oswego, OR 97035 USA
Tel: (800) 423-1625 or (503) 635-8113
FAX: (503) 635-2844
Email: info@loc-line.com/
For more information, see http://www.thomasregister.com/olc/loc-line/home.htm. An on-line distributor is Tooling On-line: http://www.toolingonline.com/storefronts/lockwood.html, A local distributor is S&J Zenith Industrial Supply (708) 339-1708. Great idea!
23 October 2001: Bill Colson (Morgan Park HS, Mathematics)
Kitty Ball
Bill obtained the hard plastic ball from Pet Smart for
around $4. It lights up when it is shaken, or when a force is
applied to it. It does not bounce well, but certainly lights up
when accelerated. Very nice, Bill!
23 April 2002: Larry Alofs (Kenwood HS Physics) -- New "Physics
Toy": Accurate Digital Thermometer
Larry showed his new Infrared Thermometer providing a digital
readout accurate to ± 0.2 °C,
which he recently obtained at Radio Shack for around $40. The device
does require a non-standard 12 V battery, which costs about $3.
The device is shown on the Radio Shack on-line catalog [http://www.radioshack.com/],
and for convenience navigating around their site, it is helpful to use
their Catalog Number: #22-325. We used this device to
measure the following temperatures in our classroom:
| Location | Temperature [°C] |
| Room air | 23.2 |
| Aim at Lights (fluorescent) |
22.6 |
| Aim toward floor | 22.6 |
| Aim toward Ceiling | 21.4 |
| Coffee pot lid | 64.4 |
| Aim at mouth | 32.6 |
| Between cupped hands: before uncupping hands just after uncupping |
- 34.6 34.2 |
| Blackboard: before rubbing after rubbing |
- 22.6 24.8 |
A beautiful gadget, Larry!.
07 May 2002: F Lee Slick (Morgan Park HS, Physics) --
Anti-gravity Fluid No 41,086
Lee brought in a friction-reduction additive that he had obtained
from Edmund Scientific [http://www.scientificsonline.com/]
some time ago. Unfortunately, the product no longer appears in
their catalog, and seems to be unavailable. This additive may be
identical or similar to the substance Polyethylene oxide [Polyox],
which is widely used in commercial applications such as water jets and
foams. [http://www.aquafoam.com]
for friction reduction in fluids. Here is an excerpt from the second
reference:
"Foam systems could contain friction reducing agents, like polyethylene oxide, which could render roadway slopes impassable – inclined ramps to highways, for instance."
Our additive is to be mixed thoroughly and completely with water to form a clear liquid. The long polymeric molecules serve reduce friction, to the extent that, under proper conditions, one could pour the liquid from one cup to another, and set up a "pipeless siphon", with the fluid continuing to creep up the side of the top cup, even after the cup is gradually tilted back so that the fluid can no longer simply spill out. This matter deserves further exploration. Come next fall ... !
Believe it or not; this is amazing! Thanks Lee!
07 May 2002: Arlyn Van Ek (Illiana Christian HS, Physics)
Illustration of Polarization
Arlyn brought in some polarizing filters which he obtained as part
of a Microwave Optics Kit. He remarked that he seldom employed the
Microwave Optics Kit, but very often used these polarizing filters
[metal sheets about 20 cm ´ 20 cm,
with parallel slots in them], as shown:
_______________________When microwave radiation falls on this sheet, only the component that has the electric field parallel to the slits will be transmitted through the filter. When two filters are in the path with their slits perpendicular to one another, no radiation can get through. Arlyn pointed out that, if you just hold the filters up and look through them, you see a good image when they are parallel, and essentially nothing when they are perpendicular. Also, by using the scroll saw to drive the transverse oscillations of a rope, as described at the 23 April 2002 (last) SMILE meeting, these sheets serve the same purpose.
| _________________ |
| '-----------------' |
| _________________ |
| '-----------------' | Polarizing Microwave Filter
| _________________ |
| '-----------------' |
| _________________ |
| '-----------------' |
|_______________________|
We began to plan experiments with microwave ovens, as described in the article in the April 2002 issue of The Physics Teacher, (see this citation): by Michael Gallis, entitled Automating Microwave Optics Experiments [p 217ff].
Arlyn began discussing why AM radio waves bounce
off the earth's ionosphere and can be detected at great distances from
the source, whereas FM radio waves [and TV signals]
are generally limited by "line of site" from the antenna. Porter
Johnson said that the free electrons in the ionosphere, which
constitute a plasma., oscillate naturally when disturbed with a
characteristic frequency known as the plasma frequency wP.
In terms of n, the number of electrons per unit volume, the
plasma frequency is determined by the electron mass m, the
magnitude of its charge e, and the dielectric constant e0 as
The same physical principles can be used to explain why a conducting metallic sheet reflects light in, say, the silvered surface of a mirror. The density of the plasma of free conduction electrons in the metal is about 1023 electrons/cm3, so that the plasma frequency is about 1016 Hz. Consequently, the frequency of visible light lies below the plasma frequency, and it is reflected by the metallic surface. Intriguing Physics, Arlyn!
10 September 2002: Larry Alofs (Kenwood Academy, Physics) Son of
"Stomper"
Larry showed a "one speed" toy available for about $4.00 at
Meijer Department Stores. These toys were manufactured by
Newbright Quality Toys, http://www.newbright.com/,
with the following description:
Product ID : 105
Description :1:43 Scale 4XFOURS TRUCK/SUV ASSORTMENT: CHEVY AVALANCHE, TRAILBLAZER & SSR, FORD F-150 THUNDER & SUPER CREW LARIAT, 2002 DODGE RAM, JEEP LIBERTY & CHRYSLER PANEL CRUISER LARIAT. Powerful motors help these rugged vehicles climb grades up to 35 degrees! All tattooed with licensed product logos and require (1) "AA" battery, not included. Item #105
Very interesting, Larry. Ann Brandon pointed out that the original 2-speed Stompers are available again at about the same price at K-Mart Department Stores. Details??
10 September 2002: Porter Johnson (IIT Physics) handed out the following list of websites involving Microwave Ovens:
10 September 2002: Earl Zwicker (IIT, Physics Emeritus) Geckos
and Coffee Filters
Earl passed out copies of a recent newspaper article describing the
discovery that Geckos, lizard-like animals native to Asia, are
able to stick to surfaces through van der Waals forces of
attraction. For details see the Lewis and Clark College
[Portland OR] Gecko
Adhesion Website, http://www.lclark.edu/~autumn/PNAS/.
Or, perhaps you prefer the German version, http://www.spiegel.de/wissenschaft/erde/0,1518,211289,00.html.
May the force be with you, Earl.
Earl also presented the following novel uses for coffee filters, courtesy of former SMILE participant Rudy Keil [source: Wacky Uses for Mr Coffee Filters by Joey Green: http://www.wackyuses.com/mrcoffee.html].
10 September 2002: Bill Shanks (retired teacher, JJC Music
Student) White Light LEDs and Bicycling Energy
Bill showed the Princeton Tec Matrix LED Headlamp Item 656480,
which he recently obtained for about $25 from REI [http://www.rei.com]:
Energy-efficient LED headlamp provides long battery life--incandescent option gives extra-bright lighting. Tailor your light with 2 different bulb-cartridge optionsAn electron passing through an LED Diode goes first through an N [electron enriched] type semiconductor, and passes into a P [electron deficient] type semiconductor. It takes a discrete downward step in potential energy, E, in passing from N to P, and may emit a photon of energy E = h f in the process. Thus, the simple LED emits monochromatic light, except for a relatively small spread in frequencies, since the potential energy provided by the batteries is somewhat greater than the potential step E. We may translate from photon energy E [in electron Volts] to photon wavelength l [in nanometers] using the formula E [eV] = 1240 / l[nm]. Thus, with two 1.5 V batteries in parallel, one may obtain 3.0 eV ® 410 nanometers, or greater, in wavelength. By picking a specific diode material, one may tune the emission frequency to a particular value. Monochromatic diodes are commonly available in red, yellow, green, and blue. Note that the visible range lies between 400 nanometers [violet: 3.1 eV] and 700 nanometers [red: 1.8 eV]. By passing blue light through a phosphorescent material, one may make white light LEDs, which produce a rather wide spectrum of visible frequencies. These light sources are rapidly being applied throughout society, since they represent efficient conversion of electrical energy into visible light. For additional details see the Dialite website Getting to Know LEDs, Application and Solutions: http://www.newarkinone.thinkhost.com/brands/promos/daillightAppNotes.pdf. We see the light, Bill.
- Efficient high-output, bright white LED bulbs provides up to 40 hours of light on just 2 AA batteries
- Incandescent bulb option supplies 2.5 hours of extra-bright light
- Wide-beam reflector brightly lights up your surroundings making it great for all-around use
- Waterproof design works well in foul weather
- Soft, 3-piece headband system provides a non-slip, comfortable fit
- Includes 2 AA batteries and storage sack
Bike Riding on the Old Plank Road Trail. In the course of his active life in retirement, Bill laid out a slightly inclined 2 mile course on the Old Plank Road Trail [http://oprt.org/], a railroad path converted into a paved cycling/running course. He found that he could maintain a steady heartbeat [as measured on his portable heartbeat monitor] of 130 beats per minute both by walking and cycling. In walking, he covered 1 mile in 12.9 minutes while maintaining that heartbeat, corresponding to a speed of 4.6 miles per hour. In cycling he could cover a mile [averaging over equal uphill and downhill portions] in 3.5 minutes, corresponding to a speed of 17.1 miles per hour. he concluded that cycling was about 3.5 times as efficient as walking, in terms of the energy required. According to standard sources, about 30 kcal are required for each mile of cycling at moderate speed, whereas 3700 kcal are required to "burn" one pound of body fat. Therefore, we calculated that about 120 miles of cycling are required to "burn" one pound of body fat, and to burn 30 pounds of body fat one must cycle about 3600 miles, corresponding to 30-50 miles per day for 75-100 days. It was his impression that these numbers significantly underestimate the effect of long distance cycling in weight control.
24 September 2002: Bill Blunk (Joliet Central HS, Physics) Slow
Motion Climbatron
Bill showed us a genuinely new Physics Toy, which he
acquired during his most recent annual pilgrimage to the Amazing
Toys establishment in Great Falls MT. [ http://www.amazingtoys.net/
for information on the establishment and discussion of one of his
previous visits see the SMILE write-up mp091101.htm].
This robotic toy, equipped with four suction-cup feet and driven by two
AAA batteries, could climb windows, blackboards, and walls. It
even "walked" on a flat table held upside down. A primitive
internal cam converted driven longitudinal oscillation into transverse
oscillations. Thus, the suction feet moved transversely,
with those on the right side in opposite phase to those on the left
side, one small step at a time. This toy is distributed by Action
Products International, Inc; Orlando FL, and listed as Item
# 56214 on the package.
Bill remarked that physics teachers should seek, find and play
with new toys in order to maintain their enthusiasm for teaching, as
well as to keep up with the technology, etc. After all, education
is a journey of discovery, and we cannot transmit enthusiasm for
discovery to our students, unless and until we genuinely feel and
display such enthusiasm ourselves. Good point, Bill, and
thanks!
08 October 2002: Larry Alofs [Kenwood Academy,
Physics] Flying Bat Toy
Larry brought in a battery-operated Flying Bat Toy, which
he obtained at the Kane County flea market. The toy was
manufactured in China and distributed by MGN Company as Item #
8-0104. He attached the bat toy to a cord that was connected to a
pivot on the ceiling, turned on the flapping wings, and released the
bat. The bat soon executed uniform circular motion of radius
R about 1 meter, in a horizontal plane. He estimated the
speed v of the bat [about 2 m/s] by timing its
revolution, and estimated the angle q
between the wire and the vertical [about 30°]. He
then applied Newton's laws to the motion of this conical pendulum,
so that T cos q = m g, and T
sin q = m v2/R, so that
22 October 2002: Roy Coleman [Morgan Park HS,
Physics] The Wicked Witch of the South
Side [Hallowe'en is coming!]
Roy, along with his accomplice Lee Slick, took photos of SMILE
participants in the levitation apparatus. For similar photos of
1997 participants, see the SMILE website
photos/photos97.html. Roy also circulated a Smart Home
Catalog, that should meet all our needs for Halloween Horror.
For example, "Greet "trick or treaters" and party guests with
awesome outdoor gear!" or "This vicious and evil looking wolf has
piercing red eyes and gargantuous fangs that say nothing more than this
pet is ready for dinner!" The Catalog is available on the website http://www.smarthome.com/halloween2002.html.
As a sequel to Roy's very informative and unusual lesson, Bill Blunk presented us the following Physics Riddle:
Q: What happens when you cross a mountain climber with a mountain goat?
A: You can't cross them, because they're scalers!
03 December 2002: Bill Blunk pointed out that refills for the four color BIC® ballpoint refills can be ordered on the web at: http://www.bicrefills.com/. You should click on "Four Color Pen" to obtain refills for models MRM41/FRM.41.
03 December 2002: Richard Goberville [Joliet Central,
Physics] Physics Toys and Cartoons
Richard passed around a Shock Pen, a Piezoelectric
device that produces a high Voltage when one presses its
cap. It is available from Johnson-Smith Catalog, http://www.johnsonsmith.com,where
it is listed as item #26074, available for around $13.
Here is the blurb:
If "office thieves" are bugging you, here's the cure. The Shock Pen's hair-raising jolt is guaranteed to stop the "borrowing." Please do not use with young children, or anyone with a medical condition. Uses one "AAA" battery, not included.Richard also passed around a "floating globe", which he obtained at a Hobby Lobby Store for about $50. A similar device is described and shown at the websites http://www.WorldGlobes.com and http://www.tradekey.com/product_view/id/69699.htm. There is a permanent magnet on the North Pole of the globe and a piece of metal at the South Pole. What holds the globe up? Richard also passed around some interesting cartoons from Garfield, Over the Hedge, BC, and The Far Side, showing important concepts in mechanics. Don't forget about The Laws of Cartoon Physics: http://www.cc.gatech.edu/classes/cs8113f_97_spring/cartoon.html. You've got us thinking, Richard!
10 December 2002: Lee Slick [Morgan Park HS, Physics]
Physics Apparatus - Cheap!
Lee told us that with a very low budget, he made physics
apparatus "el cheapo" from inexpensive stuff, but which still
showed the physics in the phenomena that he wants his students to learn
about:
"An analog to the echoes of the outdoor rotunda is the echo tube inside The Exploratorium - a 12' diameter pipe extending some 100 feet to the ceiling. Sounds created at its opening are echoed back many times, seemingly more clearly than the original sound. Sharp impulse sounds, such as a hand clap, also produce a high pitch, similar to the stylized rifle sound used in radio and TV Engineer Larry Shaw pointed out that a similar phenomena occurs with electrical impulses in our atmosphere. The sounds, variously called "chirps", whistlers", or "the dawn chorus", can be detected by attaching a coil of wire to an ordinary audio amplifier (or a barbed wire fence, as was done by composer Alvin Lucier)."
25 March 2003: Ajay Gambhir [United Scientific Supplies,
Inc] Distributor of Quality Laboratory Supplies
Ajay passed around the catalog for United Scientific Supplies,
Inc [http://www.unitedsci.com/]
which distributes science laboratory supplies to various retail supply
houses. His company is located at 4175 Grove Avenue, Gurnee
IL 60031; the telephone number is [847] 336-7556, and their FAX is
[847] 336-7571; and the email address is rsoni@unitedsci.com.
Ajay passed around the company catalog, and indicated that they were interested in supplying more sophisticated laboratory equipment appropriate for high school physics classes. His company, a wholesaler that provides apparatus to various suppliers, is also interested in evaluating interest and relevance of other equipment that is available to them. Finally, they have a more long-range goal of developing new products, based upon the interests and requirements of teachers. Ajay is interested in establishing relationships with physics teachers, in order to get advice as to how to proceed. You may contact him directly if you're interested.
We appreciate your interest in us and our program, Ajay!
11 March 2003: Bill Blunk [Joliet Central HS,
Physics] Space Shuttle Tile
Bill passed around a trapezoidal piece that was a Space Shuttle
Tile on a previous, successful mission. The exterior of
the tile was made of a hard, dark ceramic material, whereas there was a
light foam-like interior, and the tile was very light. He held
the interior with his hand and heated the exterior with a propane
torch, until the exterior began to glow bright orange.
Interestingly, he could still hold the edge of the exterior with his
hands, while this was being done. Bill was not certain
whether it is still possible to get such tiles, but will check on this
A remarkable demonstration of the insulating properties of the tiles. Thanks, Bill!
22 April 2003 Bill Blunk: How to Obtain Space Shuttle
Tiles for Schools:
The Johnson Space Center will provide non-flown Space
Shuttle Tiles to interested schools and universities. Special
handling instructions will be mailed with the tile. In order to obtain
two tiles, schools should send a request, on school letterhead paper
and signed by the school principal to this address:
NASA / Johnson Space CenterOnce a request has been received, the school will be mailed a Use Acknowledgement Form, which must be signed and returned before the tile will be shipped.
ATTN: JB / Margaret Coward
2101 NASA Road One
Houston TX 77058
22 April 2003: Bill Blunk [Joliet Central HS, Physics]
100 Year Old Spinthariscope
Bill showed us a Spinthariscope that was marked with the
date 1903. But, just what is a Spinthariscope?
The following description is an adaptation of that taken from the Kenyon
College (Gambier OH) Physics Department website; URL http://www2.kenyon.edu/depts/physics/EarlyApparatus/Miscellaneous/Spinthariscope/Spinthariscope.html
:
Alpha particles impinging on a screen coated with zinc sulfide will produce tiny flashes or scintillations of light. William Crookes [his biography: http://www.chem.ox.ac.uk/icl/heyes/LanthAct/Biogs/Crookes.html] was one of the discoverers of the effect in 1903, along with Julius Elster and Hans Geitel.The Kenyon College web page also contains a picture of the original Crookes device.The spinthariscope [dictionary definition at http://www.bartleby.com/61/44/S0644400.html] is a brass tube with a magnifying eyepiece at one end and a screen of zinc sulfide [scintillator] at the other. A small thumb-wheel allows the alpha particle stream from a uranium compound to be directed toward the scintillator. When used in a dark room, bright flashes may be seen with a dark-adapted eye.
Bill turned out the lights, and during several minutes that our eyes were dark-adapting, he described how Ernest Rutherford, [ http://www.nobel.se/chemistry/laureates/1908/rutherford-bio.html] and his associates Geiger and Marsden, established the existence of the atomic nucleus by using such scintillations. For more details on Lord Rutherford, see the biography Rutherford: Simple Genius by David Wilson [MIT Press 1983] ISBN 0-262-23115-8. Bill handed out two spinthariscopes, which we passed around in the dark room to see the scintillations for ourselves. Great!
You showed us the light! Thanks, Bill!
09 September 2003: Roy Coleman had obtained several Quartz Sport Timer stopwatches from Oriental Trading Company: http://www.orientaltrading.com, which he offered at cost, $3.00 each.
04 November 2003: Karlene Joseph [Lane Tech HS,
physics] New Pasco Track Accessories
Karlene obtained a new Pasco [http://www.pasco.com] Collision
Dynamics Track [http://store.pasco.com/pascostore/showdetl.cfm?&DID=9&Product_ID=51512&Detail=1],
as well as various accessories. In particular, she showed us a Picket
Fence Gate, used to obtain data with the ME-8930 Smart Timer:
http://store.pasco.com/pascostore/showdetl.cfm?&DID=9&Product_ID=51477&Detail=1,
which nicely and accurately determines Time, Speed, Acceleration,
and other quantities as well. Using the same projection
system as used by Larry Alofs, she proceeded to test
the reproducibility of the launcher and determined the time for the
cart to travel about 20 cm, at about that distance from the
launch point. The times were recorded to be 0.9093
sec, 0.8497 sec, and 0.6181 sec, as an indication that the
mechanical launch system is not completely reproducible. We also
observed that it took 1.3230 sec for the cart to travel a
distance of about 50 cm .She then measured the speed of the
cart using the picket fence, obtaining 44.4 cm/sec and 51.2
cm/sec for the two trials.
Karlene next set up the cart on a slight incline [standard blackboard eraser placed under one end of the track], released the cart from rest, and measured the speed of the cart: 6.4 cm/sec and 6.5 cm/sec after 40 cm, and 50.2 cm/sec and 50.5 cm/sec after 80 cm. Then she measured the acceleration of the cart directly using the Smart Timer. She obtained 12.4 cm/sec2, in rough agreement with expectations with a 1% grade. The cart was then given a push up the track from the other end -- accelerations of -22.4 cm/sec2 and -24.2 cm/sec2 were obtained. (Should the accelerations be the same? Why?) This asymmetry between going left and right was an indication that the track was not level. We did corresponding measurements on the level track, obtaining - 2.0 cm/sec2 and -8.1 cm/sec2, for the two cases. We concluded that some friction was present, and that the track was not perfectly level, the two effects being of comparable size.
Beautiful data and nicely phenomenological, Karlene!
04 November 2003: John Scavo [Evergreen Park
HS] Batteries Revisited
John showed us a model, remote-controlled airplane, which can be
recharged in a few minutes with a docking port. The Radio
Controlled Air Hog Resistor is described as follows on the Amazon.com
website:
"With a remote control that is simple to master, this two-speed airplane is perfect as a first radio-controlled toy. The Resistor takes off from its own computer-operated launch pad with a single press of the Launch button from the remote. A large toggle button moves the plane either left or right as the plane hits scale speeds of up to 400 mph and flies up to 300 feet away. For quick speed, a Thrust button on the remote gives it a 25-percent extra power boost, and for a smooth, even landing, a Land button brings the Resistor down safely. Except for a few hard plastic components that house the engine, this lightweight plane is made almost entirely of Styrofoam, which damages easily if it hits obstacles so it's best to practice flying in open, treeless areas. This toy requires six C batteries for the charger and one 9-volt battery for the plane itself and requires only a three-minute charge in the docking station before it's ready to fly."
John also showed us a remote control car [heavily battered through use!], which he had obtained for about $5. Thanks for letting us play with your toys, John!
27 January 2004: Don Kanner [Lane Tech HS Physics
Teacher] High-Tech, Low-Tech
Physics with Microsoft Train Simulator®
Don received this simulator for Christmas last year, but was unable
to install it until he obtained a new computer, since it required
2 GB of ROM and 256 MB of RAM for proper operation. For
details concerning the program see the Microsoft website http://www.microsoft.com/games/trainsimulator/.
This simulator has certainly captured the imagination of the
railroading community, and a number of additional add-ons are
available. See the 'add-ons' section of http://www.tsinsider.com/en-US/community/Pages/default.aspx.
Don found this program to be quite valuable for various aspects of physics instruction, such as making up problems, preparing for ACT exams, giving alternate assignments, and raising open questions. The program seemed to incorporate GPS data, and to have quite realistic images of its various tracks, such as the Northeastern corridor of the United States, the Odakyu Electric Railway (Japan: Tokyo & Kanagawa Prefectures), etc.With the computer set up and running in front of us, Don set up the program so that we could determine the time necessary to hit a particular speed; 60 km/hr or 16.6 meters/second, for various throttle settings. The acceleration a could then be determined from the formula a = [16.6 (m/sec)] / t( sec), where t is the time required to reach the speed. We obtained the following data:
| Throttle Setting | t (sec) | a( m/sec2) |
| 0 | ¥ | 0 |
| 20 % | 79 | 0.21 |
| 40 % | 35 | 0.47 |
| 60 % | 23 | 0.72 |
| 80 % | 15 | 1.11 |
| 100 % | 13 | 1.28 |
Don pointed out that the radius of curvature R of the track could be determined by measuring the time T required for the train moving with speed V to go through an arc length s corresponding to turn angle q:
Don has written directly to Mr Bill Gates, founder of Microsoft Corporation®, complimenting him for developing the program, and making certain suggestions as to how this program might be more useful for instruction. For example, the information on track inclination is not directly accessible, and it would be convenient to have a "display box" containing all current operating parameters in a single location on the screen. Don is (fairly) patiently awaiting a reply!
Go for it, Don --- and keep 'em rolling!
06 April 2004: Earl Zwicker passed around a catalog from the Educational Products Division of Midwest Products Co, Inc: http://www.midwestproducts.com/. Among the product categories are Competition Flying, Helicopters, Planes, Gliders, Structures, Hydrodynamics, Steam Engines, Scale Model Kits, Tools, Wood, and Styrene.
04 May 2004: Benson Uwumarogie [Dunbar,
Mathematics]
Algeblocks
Benson showed us how he uses the ETA/Cuisenaire Algeblocks system
[http://www.etacuisenaire.com/algeblocks/algeblocks.jsp]
and associated workmats [http://www.etacuisenaire.com/algeblocks/workmats.jsp]
to illustrate the concepts and manipulations of abstract algebra by
placing color-coded plastic, blocks on panels: Basic Mat,
Quadratic Mat, Sentences Mat, and a transparent Factor
Track. Connections with algebra and geometry are more evident with
this system. For example, one may use the blocks representing x,
y, and xy to build the geometric figure of area given by
algebraic equation (x+y)2. Benson has
found this system to work quite well in his classes. Thanks
for the info and ideas, Benson!
04 May 2004: Ann Brandon also showed us a novel use for an ordinary phone cord, a coiled wire that connects the handset to the main body of the telephone. These cords are available separately at low cost -- for example, try the Dollar Store. Simply hold the cord at both ends and stretch it -- the cord can be used to display transverse waves much more easily and reliably than with our usual choice, Mr Slinky. Very nice ideas, Ann. Excellent!
14 September 2004: Lee Slick [Morgan Park HS,
Physics]
Making Vectors from a "Flotation Noodle"
Lee showed us flexible, colorful foam arrow tips. He readily
attached one to the end of a meter stick, to make a "vector".
These tips were shown at a program at Chicago State University
last summer. A teacher had cut them (by hand, using a knife!) from a
long flotation toy. Lee used a band saw to make
several dozen tips. He presented a supply of them to a new
physics teacher (Tony Svozil of Homewood-Flossmoor HS) in the
audience Presumably, either a swimming pool supply house, or a store
such as Target™ or Walmart™, might have these
items. Or, they might be related to Wacky Noodles, which are
advertised in The Pool Toy Store Catalog: http://www.thepooltoystore.com/.
These are perfect for making "Bigger and Better Vectors" Great, Lee!
14 September 2004: Fred Farnell [Lane Tech HS,
Physics] Glow
Bulbs
Fred also passed around a Glow Bulb or Glow Light,
which he had obtained at a festival for about $3.00, including
replacement batteries. The device had a small housing from which a
sparking light of various colors (white, green, yellow, red,
blue, ...) was emitted when it was turned on. It was small enough for Fred
to wear as an ear ring (using a magnet to hold it on), and looked quite
fashionable. But, what are they and where can we obtain them
for ourselves? Thanks Fred!
28 September 2004: Tony Svozil [Homewood-Flossmoor HS, Physics] purchased some arrow-tipped foam flotation rods, which are called Constroodles™, at a True Value Hardware store for about $3.00. These rods were used by Lee Slick [Morgan Park HS, Physics] at the last meeting [mp091404.html] to make arrows for vectors. Constroodles™, Funnoodles™, and Soak-A-Noodles™ are distributed by Go Fly a Kite, 11 Heritage Park, Clinton CT 06413, which is a division of Jakks Pacific, Inc [http://www.jakkspacific.com/] 1 - 800 - 243-3370. Thanks for the info, Tony!
09 November 2004: 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 Yoyo:
http://www.chineseyoyo.org/index.htm.
Toys that show physics! Very interesting stuff, Rich!
09 November 2004: 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
Corporation: http://www.tycorc.com/default.aspx.
A marvelous Christmas present for children of all ages. John
also showed us a Magnetic Construction Toy [http://www.rogersconnection.com/index.html],
as well as a wind-up, spinning top that could be tossed and caught from
paddle to paddle while spinning.
Good toys, John!
23 November 2004: Bill Shanks [Joliet Central, happily
retired]
$1.00 for 3.5 meters
Bill showed us a tape measure -- with a metric scale of more than 3.5
meters! He recently obtained it at an "ultra-cheap tool bin"
at Menards for only 99¢. Bill used
the tape measure to determine the size of wooden cubes that were being
given away. He obtained 1.27 cm [or 1/2 inch], and
calculated a volume of just over 2.0 cubic centimeters. Those
cubes looked really small! Bill also showed us some
ratchet clamps, which he also obtained from Menards for about $4.50.
A good, inexpensive method of clamping and holding things. Useful
stuff, Bill!
A general discussion occurred as to why we speak of centripetal and centrifugal forces, despite the fact that forces outside the nuclear domain are either caused by contact, gravity, or electromagnetic fields. Don Kanner indicated that every centripetal force has a centrifugal reaction force, as required by Newton's Third Law. If you twirl a slingshot over your head, there is a force pulling the sling inward and the reaction force pulls your hand outward. For the moon revolving around the earth (ignoring the effect of the sun), the earth and moon actually rotate about their common center of mass, which actually lies inside the earth. Thus, the earth and the moon each experience a centripetal acceleration, caused by their mutual gravitational attraction. Porter Johnson suggested that we use the word "centripetal" to describe the direction of the force, rather than as a source of the force itself. For example, we could say that the gravitational force produced by the earth on the moon lies in a centripetal direction.
14 December 2004: Lee Slick obtained a large supply of Constroodle flotation noodles, which he first showed us at the MP SMILE Meeting of 14 September 2004: mp091404.html. Lee had obtained them as a closeout from Galyan Sports Stores, which are reorganizing at the end of the year By coupling several of the noodles into a wide "noodle plank", Bill Shanks showed us directly that the wider noodle plank is stronger under a load than an individual noodle.
14 December 2004: Bill Shanks [Joliet environs, happily
retired] LED Lantern with 12 Super Bright White LED's
Bill showed us his latest lantern, which he obtained recently at
Sam's Club. The lantern is advertised for about $15 on the
Amazon.com website [http://www.amazon.com/],
from which the following has been excerpted:
"Light up the night with this unique power lantern. With 12 individual light emitting diodes (LED), this lantern provides bright illumination that's built to last. Unlike old style lantern bulbs, LEDs rarely burn out and can glow for up to 100,000 hours! The Power Lantern includes a dimmer switch that allows you to set your own level of illumination--from low-level reading light inside your tent, to an ultra-bright torch to help light your path."
That's a nice one! Thanks, Bill!
25 January 2005: Marilynn Stone [Lane Tech HS,
physics]
Constant Speed Buggies
Marilynn showed a novel use for constant speed buggies [mp092804.html].
She tied a loop in one end of a piece of string, and attached the other
end to the side of the buggy. She then put the loop over the
vertical shaft of a ring stand on the floor. When she turned on
the buggy motor and released it, it moved on the floor at constant
speed around a circular path. Thus, she produced Uniform
Circular Motion. She measured the radius of circular path to
be R = 0.61 m, and the time for one revolution to be T =
9.6 sec. Thus, the speed is v = 2 p
R / T = 0.40 meters/sec. The buggy moves with constant
speed, but not with constant velocity. (Its direction is constantly
changing.) It experiences an acceleration toward the center of its
circular motion (centripetal acceleration) of a = v2 /
R = 0.26 meters/sec2. This acceleration is
produced by the force of tension in the string, which
continually pulls the buggy radially inward. When Marilynn
cut the string, the buggy went on a straight path thereafter. She was
able to hit a target some distance away with the buggy, by cutting the
string at the instant the buggy was headed toward the target.
Good job, Marilynn!
25 January 2005: Rich Goberville [Joliet Central HS,
physics]
New Toys
Rich kept an eye out for presents for himself while shopping for
Christmas gifts last year, and found several interesting items. He
first showed us a flexible, dilating dodecahedron produced by Hoberman
Designs [http://www.hoberman.com/fold/main/index.htm].
This device is a variation of the more familiar Hoberman Sphere.
The gadget, called a FlipOut!, magically changes shape and
colors when thrown into the air: http://hoberman.com/fold/flipout/flipout.htm.
Rich also showed off his new HoverCopter Radio Controlled Flying Saucer: http://paranoidnews.org/2010/12/pp37-hover-copter-the-radio-controlled-ufo-flying-saucer/. It serves as a more dramatic device than a toy helicopter to illustrate Newton's Third Law as the explanation for aerodynamic lift. The downward draft of the toy helicopter is rather mild, but you can point it sideways, and definitely Feel the Breeze! The radio control permits it to go up and down, but it is rather difficult for the device to hover --- as it is for real helicopters.
Neat stuff, Rich!
25 January 2005: Bill Shanks [Joliet - New Lennox Environs,
retired]
Point n Measure Digital Tape: How Far?
Bill recently obtained Point n Measure Digital Tape
[Item W5746] at Menard's for about $9. He turned it on,
pointed its laser beam at a nearby wall, and showed the recorded
distance as 5.01 meters (or 16 ft 5 in). We then made
estimates for the area of our classroom, ranging from 60 meters2
to 120 meters2. He then used the gadget to
measure the length of the room L = 11.17 meters (36 feet) and
the width W = 7.64 m (25 ft), corresponding to an area of
85 meters2 (900 square feet).
Very nice gadget! Thanks, Bill!
25 January 2005: Roy Coleman [Morgan Park
HS, physics] Push
N Go
Roy showed us a small car, called Push N Go, which is
available in bulk at about 50 cents each from Oriental Trading
Company http://www.orientaltrading.com.
He uses this car, as well as its larger counterpart, for having
students observe its motions, and draw graphs of Displacement,
Velocity, and Acceleration versus Time, as described recently [mp092402.html].
He found that students were reasonably accurate in their descriptions
of Velocity and Acceleration versus Time, but often quite in
error for Displacement
versus Time. That graph, although most closely related to
observations, is challenging for many students.
22 February 2005: Bill Shanks [Joliet and New Lenox
environs, retired]
Laser: Cheap!
Bill showed off a new laser that he had obtained as a
"remainder" at a Cummins Tools store: http://www.cumminstools.com/index.htm.
The device contained a red laser beam driven by 3 button cell batteries,
a hologram of a swan attachable to the front, a sonic
blaster, and a Green Flashing LED. On the package it
said "This is not a toy!" -- but -- "Why does it chirp
like a bird?"
We attached the hologram to the front, and looked at the resulting
pattern. Then we compared it with a more powerful and more
expensive Green Laser provided by Bill Blunk.
Interestingly, one could see the path of the Green Laser
beam more readily than the red one, especially by standing behind it
and looking within about 10 degrees of its direction. Of
course, both
beams
were easily visible when chalk dust was scattered along the paths of
the beams.
Very impressive gadgets! Thanks, Bill!
29 March 2005: Ann Brandon [Joliet West,
physics]
Masses for the Masses
Ann showed us a set of brass slotted weights (including calibrated
hook) that she had recently obtained (cheap!) for $9.00 from a Science
Kit catalog, although the package referred to Edmond Scientific.
Since the science supply houses don't actually manufacture very many of
their products, the same items are often available from several of them.
Bill Blunk compared the mass of a 5 gram brass weight with that of a Nickel coin -- approximately 5 grams. He placed the brass weight at one end of the meter stick, placed a Nickel at the other end, and used a pencil as a fulcrum to balance the stick at the middle. The balance was good, and the stick remained balanced when the positions of the Nickel and brass weight were switched. Nice weights, Ann! Nice test, Bill!
12 April 2005: Ann Brandon provided more complete information as to the Slotted Mass Kits [13 masses total; 5 to 50 grams; B-grade Brass; with 50 g hook]. These are available from the following sources:
12 April 2005: John Scavo [Kelly
HS]
Christmas Toys, Revisited
John showed the deluxe radio-controlled car, obtained on sale at Navy
Pier for $20 -- in contrast to the usual price of $85. It
would accelerate, do flips, reverse direction, and turn around -- all
on radio command! John also explained that the
cheapest dry cell batteries often last the longest, since durability
seems to be correlated with the thickness of the metallic battery
case. A very nice gadget to give to an 8 year old, John!
John next mentioned Magnetics: a set of 250 pieces [steel balls and magnetic shafts of various lengths] that could be used for building tetrahedrons and other stick-figure geometric structures. He had obtained the set for $9.99 at Walgreens™, although more expensive sets are available elsewhere. Charlotte Wood-Harrington pointed out that the various sets may have incompatible "building blocks", as she found to her dismay when her family received several sets for Christmas.
Finally, John mentioned that the Erector Set™ is still available --- and still a classic, although it is no longer manufactured by Gilbert. Thanks for showing us your toys, John!
13 September 2005: Paul Fracaro (Joliet Central HS,
physics) CBL System
Paul demonstrated math and physics lessons on the CBL
(Calculator Based Laboratory) System. A collection of lab exercises
is available in these disciplines, as described in the following books:
Paul demonstrated the ultrasonic position detector/probe as an example. He projected the screen from the calculator onto a large movie screen in the front us, so we could follow along as he walked us through the software. The sensor was linked to an interface, which in turn was linked to a TI-83 calculator. For example, the calculator plotted a distance versus time relationship as Paul walked backward and then forward, as the sensor detected his position. Using the same setup, Paul walked forward and backward over a time interval of about 5 seconds. A plot of position versus time showed up on the calculator/screen, from which the velocity could be obtained by clicking on two points on the graph. Paul tried to walk so as to match the following graph of position versus time, using the detector to record his positions:
He found it surprisingly difficult to move with a constant velocity, although it was rather easy to be at rest. Detection probes are also available for sound, magnetism, electricity, temperature, force, etc. Paul described a nifty experiment on Newton's Law of Cooling using the temperature probe. Simply wrap the probe in aluminum foil, heat it with a blow dryer, and take data on temperature versus time, yielding an exponential curve. Neat stuff, Paul! Thanks.
13 September 2005: Ann Brandon (Joliet west,
retired) NSTA Magazine
Ann shared with us the September 2005 issue of the NSTA
Science Teacher magazine, which emphasized safety in the
classroom. There was a great article on doing chemical flame tests
safely and an article showing a sharp increase in accidents in
science labs as the number of students in a classroom grew to exceed
24. Thanks, Ann!
20 September 2005: Ann Brandon
Ann gave away some GE Magic Cubes, which she had found in
a recent housecleaning episode. These old fashioned photo flash cubes
were known as Magic Cubes because they could be flashed without a
battery, by touching both terminals with a wire. They are very
useful for studies of chemical reactions. [Flash cubes can still
be obtained from Wizard Devices Inc: http://www.wizard-devices.com/flash.shtml.]
Splendid! Thanks, Ann!
04 October 2005: Charlotte Wood-Harrington (Gwendolyn Brooks HS,
physics) Cheap
Constant Velocity Cars
Charlotte found an internet source for "flip over buggies" [http://www.joissu.com],
where they can be obtained at $1.29 each, in lots of 50.
They can also be ordered from Flinn Scientific [http://www.flinnsci.com/] for $
7.95 each. They run on a C-cell battery, which is not included. These
buggies travel along very straight paths, and are quite useful in
showing and visualizing aspects of motion at constant speed.
18 October 2005: Roy Coleman (Morgan Park HS,
physics)
Air Gyroscope made from a Bowling Ball
In 1968 Roy took a course with Harald Jenson at
Lake Forest College, which inspired him to build an air
gyroscope [http://www.physics.umd.edu/lecdem/services/demos/demosd4/d4-10.htm]
using a bowling ball. A bowling ball (with a metal rod about
10 cm long and 1 cm in diameter that was threaded radially
into the ball) sits with its bottom half resting on a hemispherical
plaster cast of itself and mounted at the top end of a metal
cylinder. A vacuum cleaner is used to flow air into a tube
leading to the bottom of the hemispherical plaster cast.
Subsequently, when the ball is placed into the hemisphere, it is
supported on a nearly frictionless film of air flowing between
it and the plaster. Once the ball is rotated with the help of a hand,
it continues to spin, and it precesses and nutates
-- both are easily seen in the motion of the rod above the ball.
Roy used this project for his Masters Thesis at Loyola
University. Roy's description of this Bowling
Ball Gyroscope appeared
in the journal The Physics Teacher [http://scitation.aip.org/tpt/]
in 1970. In a short ceremony -- and with our
applause! -- he gave the apparatus to Debbie Lojkutz , who
had used
and broken this apparatus when she was Roy's student at
Morgan Park HS some years ago. Roy remarked that, over the
years four students had severely damaged physics laboratory
equipment --- and that all four of them have become physics teachers.
Interesting! Thanks, Roy.
07 February 2006: John Scavo (Kelly
H.S.) The
Mousetrap Car
John showed a mouse trap car that he obtained from Hobby Lobby for
about $10 for his third grade son. The kit for construction of the
mouse trap car is made by Doc Fizzix: see the website http://www.docfizzix.com/. The
kit is made from simple items that you could find at hardware stores,
hobby stores, etc. (balsa wooden pieces, clear CD's for wheels,
Elmer's Glue® for assembly, etc.). A thread was wrapped a
number of times around one axle, and was hooked over a metal arm
attached to the spring mechanism of a strong, but ordinary mouse trap.
When the arm was released it moved back slowly as it pulled the string,
causing the axle to turn and the car to move. According to the
instructions, the trigger from the spring mechanism is removed, for
reasons of safety. It traveled for about 18 meters ( 60 feet),
coasting to a stop after the spring was completely unwound. This
is short of the current record of about 111 meters!
Keep on trucking! Thanks, John.
07 March 2006: Bud Schultz (Aurora Middle
School) Gonzo Gizmos
Bud shared a book he bought at American Science and Surplus
-- Gonzo Gizmos: Projects & Devices to Channel
Your Inner Geek by Simon Field (http://www.kk.org/cooltools/archives/000667.php).
This book is full of great ideas, explanations, and projects -- it
contains a lot of interesting activities involving electricity. Thanks
for the Info, Bud!
