SMILE MATH-PHYS Meeting
10 November 1998
Notes prepared by Alex Junievicz

Arlyn Vanek [Iliana Christian HS]

Students like to do things with weapons in physics labs, so he developed experiments with his bow. (His dad thought this was safer than a b-b gun, for some reason!) Hang a weight from the bow and measure the stretch.

W = fd PE = mgh KE = 1/2 mv² = PE Work is the area under the curve of force versus displacement

                                   .----- . archery bow
                                      W
                                      e
                                      i
F (Nt)  x (meters)                    g
                                      h
 00       .0                          t
 10     .020             Now plot the data, and it will be a straight line
 30     .070
 50     .122                   F  |              .
 70     .188                      |           .
 90     .255                      |       .
110     .321                      |    .
                                  | .
                                  |____________________

W = 1/2 fd = PE

If shot straight up, what is its speed and how high it will rise? [Ans ? 27 m/s and 35 m].

Ann Brandon [Joliet West HS]
remarked that the fit is not exact and any anomalies that arise could be discussed by asking the question What are the sources of error?

Carol Zimmerman [Lane Tech HS]
commented that she has 6 older computers set up with Vernier programs so that the students can graph items (6 computers and 3 printers)

He showed some magnetic stick figures that may be obtained through Heart Strong Corporation: 1-800-325-2502 or 412-613-0371. Web address is: http://www.heartstrong.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).

Larry Alofs [Kenwood Academy HS]

He showed the Pasco Mini-Launcher (circa $125 in 1997 catalog). The assembly has a spring and gimbals that allow it to be aimed. He did not initially know the speed of the ball upon launch, so he pointed it up--it traveled 143 cm high (launch speed: 5.3 meters/sec. With photocell gates it was measured to be 5.27 meters/sec) At a launch angle of 60^o to the horizontal we calculated a rise time of 0.47 seconds, or a flight distance of 2.48 meters. After launch the ball hit a pan at the distance of 2.48 meters. Next he tried 60^o and the distance was again 2.48 meters. Next he adjusted to 45 degrees, and fired... Did it again hit the dish at 2.48 meters?? Nope!!!

John Bozovsky [Bowen HS]

With the earth represented by a beach ball 40 cm in diameter, how far away would the sun be? He showed a video tape he made. He walked and drove and drove until he went from Bowen HS to (familiar landmarks??) 95th and Cottage Grove.

Distance to the sun  =   2.87 miles at perihelion [Jan 6]
                     =   2.97 miles at  aphelion [6 months later]

          X [cm]               93,000,000 mi
      _____          =    __________________

         40 cm                      8,000 mi

John went on to indicate that his geology class is studying earthquakes, and has discovered that they occur very frequently somewhere on earth. Porter Johnson commented that there is a peak earthquake season around May (thermal expansion of the earth is the suspected culprit!) but that earthquakes can happen at any time. The recent [7.0 Richter Scale] eruption of the San Andreas Fault had its epicenter at Santa Cruz, which is precisely where a team of earthquake geologists had gathered to investigate the seismic anomalies.

He slyly commented that, in an earthquake you can tell which direction it is coming from by listening to where the auto alarms are going off ... just as we had a glitch in the electric power in the building. [In LALA earthquake land it might have been the big one -PJ.]

Alex Junievicz [CPS Substitute]

He made 2 comments, First he brought a maze that helps get the difference between Distance/Displacement across. Find the route through the maze, measure it in meters (expand the relationship of cm to m) and the figure out the displacement (direct vector route) in meters and direction. remember North is zero...or use the meteorological ESE East-South-North-West, etc.

Second, he mentioned a way of keeping electrical meters from being destroyed. By placing at least 2 silicon diodes in opposite directions across the movement, thus the voltage should not exceed .6V saving the meter. if .6 V affects the full scale readings, 2 can be put in series--1.2 V. Another device used for protection is the neon bulb which fires at about 90V depending upon ambient light.

Earl Zwicker [IIT Professor Emeritus and SMILE guru]

He brought in copies of the Chicago Tribune article of 11-9-98 about Search for Extraterrestrial Intelligence. The web site is http://setiathome.ssl.berkeley.edu

Bill Blunk [Joliet Central HS]

He brought in the address of his favorite Science Store.

 19 Central Ave          (Should we have a SMILE field trip??)
Great Falls MT 59041
TEL:  1 - 406 - 727-5557