Chemical Education Today
Especially for High School Teachers by Erica K. Jacobsen
Classroom Credit
photo by Lois J. Bode
www.JCE.DivCHED.org
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Secondary School Featured Articles 䊕 A Cool Drink! An Introduction to Concentrations, by Mindy Bedrossian, p 240A—B. 䊕 Fractional Distillation of Air and Other Demonstrations with Condensed Gases, by Maria T. Oliver-Hoyo and William L. Switzer III, p 251. photo by Mindy Bedrossian
“It’s everywhere you want to be.” Readers versed in television jingles may remember the above phrase from the commercials of a well-known credit card company. While television has connected this familiar tagline with visions of retail purchases, it recently came to mind as I reflected on the different ways people use JCE Classroom Activities. This past fall, my eight year-old niece needed a topic for a science fair project. My mother was going to be guiding her through the process, and asked me for possible topics. I suggested the recent Activity “A Magnetic Meal” (1). It used the familiar substance of breakfast cereal to provide a surprising result, had suggestions for further investigation, and could be performed in the home. Did it matter that they didn’t have access to a balance with an accuracy of 0.001g? Did it matter that she didn’t know how to write a balanced equation for the reaction of iron with hydrochloric acid? No. The parts of the Activity that were too high a level for her were easily adapted. They didn’t weigh the iron obtained, but showed its presence on a coffee filter. They omitted the reaction with HCl, but included the familiar sight and color of rusted iron. The project was a success and even led my niece to seek out a book on vitamins and minerals and read it out loud to my mother, the two of them discussing the ideas as they went. With judicious adaptation, Activities really are everywhere you want to be— classroom or home, and nearly any grade level. The flexibility of Classroom Activities to cover any theme is another plus. JCE typically offers Activities that match each year’s themes for both National Chemistry Week and Chemists Celebrate Earth Day. Turn to p 240A–B for this year’s Earth Day Activity, “A Cool Drink! An Introduction to Concentrations”. Bedrossian uses the simple items of presweetened powdered drink mix (Kool-Aid), water, and disposable cups and spoons to create an Activity that touches on the varied topics of serial dilution, parts per million, molarity, and air pollution. It has students calculate how much mercury a person may safely inhale daily, according to the EPA safety levels. It ties in well with this year’s Earth Day theme of “Air: Here, There, Everywhere”. If I may borrow another credit card tagline: “KoolAid: $3. Packages of disposable cups and spoons: $2. A chemistry Activity that can be used immediately to create enthusiasm for Earth Day 2005: priceless.” Teachers using the above Activity may also wish to further extend their discussion of mercury in the environment. In their introduction, Rice et al. (p 265) discuss a site of massive mercury contamination located in the U.S. state of Georgia. Industrial tenants released in excess of 400,000 pounds of elemental mercury into the surrounding salt water estuary over
䊕 The Determination of the Percent of Oxygen in Air Using a Gas Pressure Sensor, by James Gordon and Katherine Chancey, p 286.
a period of about 20 years! The authors describe the impact on mercury levels in seafood. While high school instructors will probably not use the described lab activity because of the required instrumentation, the data and information it contains certainly provide relevant discussion material. Foster (p 269) discusses the consequences of broken mercury-in-glass thermometers, and her department’s actions to find accurate and safe thermometers for laboratory use. Students might be interested in her statement “It has been estimated that the cleanup cost of one broken mercury thermometer is about $75–$110 and that the one-half gram of mercury contained in a mercury thermometer is enough to pollute five million gallons of water.” One of this month’s Chemical Laboratory Information Profiles (CLIPs) also presents information about mercury and its hazards (p 203). Why not hand out a copy of this CLIP to students? The format is easy to follow and understand, and can lead to a discussion of acceptable exposure limits of various chemicals. ACS Teaching Excellence Endowment Last month’s issue included an announcement of a new campaign of the ACS’s Division of Chemical Education. The Division is establishing the “Teaching Excellence Endowment” to support awards for high school science teachers in every ACS Region. Their goal is to raise $300,000, with the first $100,000 in contributions to be matched 1:1 by DivCHED. This is an excellent opportunity to support and reward deserving high school teachers—those who continually motivate and encourage students to study chemistry. By the time you read this, I’ll have sent in my own contribution, in honor of my excellent high school chemistry teacher (my dad!). Please consider lending your own support. Literature Cited 1. JCE Editorial Staff. J. Chem. Educ. 2004, 81, 1584A–B.
Vol. 82 No. 2 February 2005
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Journal of Chemical Education
185
