SMILE Mathematics-Physics High School Meeting
26 October 1999
Notes taken by Earl Zwicker

...John Bozovsky (Bowen HS),

rushing the season perhaps, explained wind chill temperatures to us. (handout) For example, 0oF is equivalent to -22oF in a 10 mph wind. This is cause the wind lowers body temperature byu evaporating perspiration off the surface of our skin and blowing body heat away. The effect increases with wind speed. A graph of wind chill temperature vs air temperature at any given wind speed are approximately straight lines that converge at the warm end - about 85o F or so. Using the data handout from John to make such a graph is a good exercise for students. And now we can figure the wind chill on Hallowe'en, with wind at, say, 20 mph! Thanks, John!

Larry Alofs (Kenwood HS)

had showed us "action at a distance" very real graphic. A small board (maybe 12 in long) had a clothes pin fixed at one end, and a vertical board (about 7 in) at the other end, with a cow magnet held on top. A piece of string had a paper clip tied to one end, and the other end was held by the clothes pin. The paper clip was held near the magnet, and the length of the string adjusted (using the clothes pin as a clamp) so that the attractive force between magnet and paper clip held the string stretched out toward the magnet, with no visible means of support. Striking! One could study effectiveness of the magnetic shielding of various materials using this. Larry had cow magnets for sale at cost, about \$2.50 each. Beautiful!

Bill Colson (Morgan Park HS)

told us about the Intel Virtual Microscope, and then about New Scientist Magazine (www.last-word.com) with science questions and answers. And then we learned about the Biltmore Stick for measuring tree heights. Neat! PJ Comment: It is important to distinguish the last word from the last words.

Bill Blunk (Joliet Central HS)

showed off his mini video camera (Sony NTSC color camera, CCX-Z11) \$90 plus shipping (handout: from All Electronics Corp, 1-800-826-5432, PO Box 567, Van Nuys, CA 91406-0567, www.allelectronics.com, Cat # VC-1100, includes ac power adapter, audio/video cable and instructions). He hooked it up to SMILE's 12 inch monitor and we could see ourselves "up close and personal." Using Quicktime Graphics on a PC, users can see each other! Putting a lens close in front of the camera enabled us to see an upright image; farther away the image became inverted. A bigger TV is more impressive.

Bill also showed us a rocket launcher contrived from paper clip, matches, aluminum foil. All wonderful ideas!

Bill Shanks (full time music student now; Joliet Central HS, ret.)

showed us a free ISPP Giveaway: a film canister with a 5/8 in hole in base and cap. Put plastic "drumhead" over canister and snap cap on to hold. A 3/8 in hole is on the side of the canister. Blowing in the hole generates a sound of a particular pitch. A PVC pipe to fit into the 5/8 unconvered hole enables one to effectively double the length of the canister, reducing the pitch by one octave! Innovative!

Ann Brandon (Joliet West HS)

(handout) did Physics Off the Cliff (Conceptual Physics) with us. How long would it take a steel ball bearing (slingshot amenities, K-Mart) to fall from the top of a table 0.79 m high and strike the floor? Using h = gt2/2, knowing h and g, one calculates t = 0.40 s. We rolled the ball off the end of a horizontal table, observing that it took 1.55 s to roll 1.0 m off the end, so it had an initial horizontal velocity of 1.0 m/1.55 s = 0.63 m/s. Moving horizontally with that velocity while falling for 0.40 s to the floor, it would strike the floor at (0.63 m/s)(0.40s) = 0.25m from below the table edge. On target, observed! A beautiful way to show the independence of horizontal and vertical motion!

Roy Coleman (Morgan Park HS)

showed us his GPS Locator (\$199) by Garmin. On its screen it has a resolution of 0.1 mile, it computes magnitude and direction of the speed of the vehicle in which it is mounted, and has a resolution of 5 ft. It gave us our location as 40o 50m.317 latitude, and 87o 37m.858 longitude. Works outside only, and shows the path home. Remarkable!

Earnie Garrison (Jones Commercial HS)

showed us "Pigs in Space." He used a "Mirage" (two concave mirrors facing each other, with hole at the "center" of one for the formation of a real image of an object place at the center of the other. Am Sci Ctr). A small "pig" object placed inside on the bottom mirror had its real image displayed at the hole of the top mirror. You try to grab the pig, but it isn't there! Bill Blunks mini-video camera displayed the image on the screen, showing that it is a real image! Isn't it great how one idea works to help another at the same meeting!?

Great meeting! Don't miss the next one!