Note: Porter Johnson announced that the syllabus for courses in the SMILE program is located on the SMILE website at http://www.iit.edu/~smile/syllabus.htm. A signed copy of this syllabus can be obtained at SMILE meetings.
Roy Coleman [Morgan Park HS] demonstrated a searchable CD containing SMILE and SMART lessons (written by teacher participants in these two programs) dating back to 1986. They are available from him for only $10.00 (less than one cent per lesson!) or $5.00 and an earlier version of a SMILE CD, As a bonus, he suggested that we try the following phenomenological experiment with an "unwanted CD," e.g. the free ones you get in the mail from internet service providers. Place the CD in a microwave oven and heat for 4-5 seconds (NO LONGER! unless your microwave oven is also unwanted). He promised "interesting results" but didn't say anything about wearing safety garments. Question: Did this get started by someone accidentally putting a CD in a microwave (stuck to the bottom a the mashed potato dish), or put there by a curious child (who might grow up to be a famous scientist), or .............
Registration, applications, and other admnistrivia were conducted; then Ken Schug made several phenomenological presentations from his "shoeboxes he uses when teaching the general chemistry course at IIT. We also signed up for date to share phenomenological presentations with our colleagues. (see below)
He held up a gallon size clear kitchen bag and asked for advice on how to fill it with air. When there was agreement that swooshing it was preferable to exhaling into it because exhaled breath has a different composition from air (less oxygen and more carbon dioxide), he swooshed, closed the opening with a twist tie and hung the bag on a clamp on a ring stand. He then took another bag from the same roll, poured in about 30 mL of 3% hydrogen peroxide solution, added a package of dry yeast and applied a twist tie. We observed foam forming, the bag expanding in size, and (by three teachers in the front row) a report that heat was being given off and concluded that a chemical reaction was occurring. Ken pointed out that hydrogen peroxide, H2O2, is one of only two compounds containing only hydrogen and oxygen stable under normal conditions (the other, of course, is water) and that, although it contains more stored chemical energy than a mixture of water and oxygen gas, the rate of the reaction to form these products is very slow in the absence of a catalyst. Yeast is one of many chemical or biological substances that can serve as a catalyst for that reaction.
He then lit a cigarette and touched the glowing end against the bag containing air; we observed that the cigarette melted a hole in the bag. When he did applied the cigarette to the other bag, however, the bag burst into flame, which continued for several seconds, consuming about one third of the bag. Ken asked for hypotheses to explain this event and accepted the suggestion that the higher concentration of oxygen was responsible. The higher concentration resulted in a chemical reaction fast enough to keep the fire going. (Ken pointed out that if more hydrogen peroxide had been available for the reaction, the effect would have been much more dramatic.
Ken then held up a flat bottle containing a medicine dropper floating (vertically) near the surface which several teachers recognized as a Cartesian diver. He passed the bottle around and heard several comments that the bottle seemed to made of glass; not plastic. He confirmed the it was indeed a glass bottle and got several predictions that the dropper would not submerge when the bottle was squeezed because you need a plastic bottle for Cartesian divers.. He then gave everyone a chance to test that hypothesis phenomenologically by squeezing the bottle, discovering, amid oohs and aahs, that "it worked!" After an explanation that the "diving" occurs because squeezing the flat sides of the bottle slightly reduces the volume which results in an increase of pressure inside the bottle (which is completely filled with water and is tightly capped.
Since the dropper is partially filled with air (the liquid-gas interface was just visible below the bulb) the increased pressure forces more liquid into the dropper as the volume of air decreases slightly (Boyles' Law in action!), which makes it heavier, so it sinks. [Submarines use the same principle] Instead of taking a bow, Ken said, "wait a minute, I'm not finished" and, with the aide of an assistant, extended the experiment. As the assistant pushed steadily on the front and back flat sides of the bottle to keep the diver submerged, Ken pushed on other two sides (perpendicular to the aide). We observed the diver return to the top of the battle, We decided that pushing on the edges cause a slight outward bulge of the flat sides, resulting in an increase in the internal volume, expansion of the gas in the diver (making it lighter) and causing it to rise to the surface.
Ken then opened another shoebox, took out a jar of all purpose flour and poured some on the top surface of an inverted (empty) tuna can, saying He was going to see if flour could be used as a renewable source of energy. When he held a match against the flour, there was a little charring but not a sustained flame, a necessary requirement for a successful energy-producing combustion. He then poured some flour into a plastic funnel with a long piece of rubber tubing attached to the exit, turned out the light, struck a match and led it above the funnel as he blew forcefully into the tubing. When the flour cloud reached the burning match we saw a ball of flame shooting up toward the ceiling.
After some discussion, we concluded that the difference in behavior of the flour in the two parts of the experiment was due to the fact that as a "cloud" each particle of flour has many oxygen molecules from the air surrounding it but in a pile most of the space around each flour particle is occupied by other flour particles so the reaction is slower and does not proceed fast enough to keep the combustion going,
In retrospect, the first and third experiments demonstrate the four major factors that can affect the rate of a chemical reaction:
SCHEDULE (All Tuesdays)
|September 24:||Chris Etapa||Pat Riley||Marva Anyanwu|
|October 8:||Teri Roland||Ed Scanlon||Therese Donatello|
|October 22:||Christine Scott||Lil Green|| Gary Guzdziol|
(Ed's Son, welcome!)
|November 5:||Frana Allen||Tyrethis Penrice||Carol Giles|
|November 19:||Barbara Lorde||Wanda Pitts||Winfred Malvin|
|December 3:||Carl Martikean||P. Bahl|
[ ... ... Note one week gap ... ... ]
|December 10||J. Desai|
Notes taken by Ken Schug.