Barbara Lorde [Attucks Elementary School,
science; grades 3-8] Making a Plastic Toy
Barbara warmed one cup [250 ml] of milk in a saucepan for a few minutes, and slowly stirred in 5 tablespoons [75 ml] of vinegar. The casein [a milk protein] and fats separated out, because the drop in pH (increased acidity) caused them to become insoluble. A rubbery mass was initially formed, but eventually it began to harden into a plastic consistency. She then added food coloring to the casein during the class, to make it more interesting. This casein-fat mass can also be squeezed or placed in a mold to produce a "toy" after hardening. She also suggested that you could bring in ratios and proportions in a practical context, as well as convert into metric units. An interesting Chemistry lesson, as well as ...
... artistic, Barbara!
Tyrethis Penrice [McKinley
Water vs Hard Water
Tyrethis called our attention to the following websites on Soft Water: http://pasture.ecn.purdue.edu/~agenhtml/agen521/epadir/grndwtr/softened.html and http://scifun.chem.wisc.edu/HOMEEXPTS/SOFTWATR.html. Then we performed the experiment described in the second website, making our own hard water by mixing 1 teaspoon [5 ml] of Epsom Salts [MgSO4] to 1 cup [250 ml] of distilled water. We added several drops of liquid dish detergent to this mixture, as well as to an equal amount of distilled water. We were not able to produce as much suds with the artificially hardened water, in comparison with distilled water. Still, the difference was not as great as we had expected. Why?
Good Chemistry for everyday life! Thanks, Tyrethis!
Chris Clausing [Bloom Trail HS]
Chris made a Powerpoint™ presentation using the interactive CD- ROM Inorganic Nomenclature, which can be used by students on their own computers, and which tabulates scores. The CD-ROM was obtained from the Johnson County Community College in Kansas. For more information contact Donnie Byers: email@example.com.
Chris modified the making compounds section of the CD by making game pieces out of cardboard to represent ions:
Monovalent, divalent, and trivalent positive and negative ions are represented by pieces, as shown, and compounds are made by fitting the pieces together. For example, the assembly dissociation of H20 is represented as follows:
Chris has also developed a program called Chemistry in the Schools [CITS], in which he teaches high school students who, in turn, teach 4th and 5th graders. They use exercises such as freezing a banana in liquid nitrogen, and then using the frozen banana to drive a nail into wood. For more information on this program, contact Chris.
Terrific stuff, Chris!
Barbara Pawela [May School,
Barbara made a presentation based upon a lesson that she developed in SMILE in Summer 2000, which consisted of the following activities:
Scheduled Future Presentations:
Notes taken by Ben Stark.