Lee Slick (Morgan Park)
Lee started up a rebus, actually a series of them, each being an element: Sodium, Carbon, etc. By the way, a rebus is a set of pictographs, symbols, and operations to represent a word or phrase. For example
"picture of needle and thread" + D + "picture of a pack of gum" - G = SODIUM
Get it?? A terrific way to engage kids as they learn about the chemical elements.
Chris Etapa (Gunsaulus School)
Chris began by outlining a presentation to emphasize the importance of laboratory safety. In her class she took a raw egg and put it into a petri dish placed on the overhead projector. Then, she added 2 drops of dilute Hydrochloric Acid [HCl]. As the protein "denatures" it looked dark on the screen. This graphically illustrates the need to wear safety glasses, since our eyes contain the same types of protein as egg proteins, with the same sensitivity to acids.
Next she presented two mini-labs, which are used to get kids into a "science fair" mode.
Pat Riley (Lincoln Park HS)
Pat asked us how we might make a reaction --- such as dissolving sugar in water --- go faster. Suggestions included the following:
heating, stirring, breaking sugar into smaller pieces
As to the effect of breaking sugar into smaller pieces, we suggested a refinement, since the surface area was increased and the particle size was decreased. [In this sense the "particle size" refer to the size of individual sugar molecules]. Which of these effects is more important? She considered these two balls of the same size:
The Styrofoam™ ball has more surface area and should have more "sticking power". Similarly, the increase in surface area, although it does not change the size of each sugar molecule, is the key parameter for speeding the reaction rate.
Therese Donatello (St Edwards School)
Therese presented the following three exercises.
Then she pulled on the papers, the cuts making it easier for the paper to
start tearing. We investigated finding how to tear the paper most
easily; that is, was it better to pull slowly, quickly, from the sides, from
opposite ends, etc. If the tearing is uneven and not the same for each
layer, it may be because of the different compositions of paper in the various
layers. This illustrates how movements in the earth's crust can lead to
earthquakes. Very nice, Therese!
The paper clips were made of different materials, such as metal or plastic.
We noted that the smaller clips bent more than the larger ones, and even with
clips of the same size there was variation in bending because of the different
material composition. Also, with smaller stacks of paper the clips stretched,
but rebounded when the paper was removed. By contrast, with sufficiently large
stacks of paper the paper clips would stay deformed after the paper was
removed. Evidently, the clips had reached their elastic limit, and
their shape was irreversibly altered.
|Stretch Factor||Measured Length|
|1 ´||9.5 cm|
|1.5 ´||9.5 cm|
|2.0 ´||9.5 cm|
|2.5 ´||9.5 cm|
|3 ´||9.5 cm|
|4 ´||9.7 cm|
|5 ´||10.0 cm|
Notes taken by Ben Stark