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“Why, mom?” Does the above question sound familiar? Maybe too familiar? Questions of all kinds are part of a child’s repertoire—“When do we…” “How does it…” “What can I…”, with infinite variations. Sometimes we know the answers, sometimes we don’t. There are even World Wide Web sites devoted to answering questions. I often come across How Stuff Works (accessed Jul 2005) when searching for Web sites to recommend on the student side of JCE Classroom Activities. The site provides easy-to-understand answers to questions many of us may have wondered about from time to time. For example, a recent Activity led me to “How does glow-in-the-dark stuff work?” and its accompanying answer. This month’s JCE Classroom Activity “Colors in Liquid Crystals” might raise some questions of its own. - Why would I choose to do this activity when it requires special chemicals that are a bit pricey?
- Why would I choose to do this activity when it seems fairly high level?
- Why should I even try it?
As one who has tried the Activity, I encourage you to try it as well. Why? The materials of the Activity hold universal appeal. Most, if not all, of your students have probably used a liquid crystal at some point in their lives. The Activity mentions a few such as calculators, mood rings, and battery test strips. But even though liquid crystals are widely used, students may not have considered how they work. I have a refrigerator magnet with a liquid crystal thermometer—after testing the Activity, even I took a lot closer look at how it operates. Readers will also be interested in additional liquid crystal background information presented by Van Hecke et al. Why? The topics covered by the Activity adjust to fit any audience. Younger students can observe the order of the colors seen as the liquid crystal cools. Do they appear in the same order every time? How does it relate to a rainbow? Advanced students can handle a discussion of the Bragg equation mentioned on the Instructor Information side. The Activity is even suitable for a make-and-take outreach project. Why? It’s just fun and super cool! Students easily make their own “sandwiches” of liquid crystals, and may take them home to show to family members. The color change occurs over and over again. You’ll observe that even though you might see red when looking at the liquid crystals over a dark background, you’ll see the complementary color green when holding it up to a white light source. The chemicals cost about $75, but the amount is enough to last for multiple uses. You might wish to split the cost with another teacher, or save additional chemicals until next year (see the Activity for how to keep the mixture from degrading), or use the remainder for an outreach project or science booth. Or, might a chemistry supply company consider offering smaller amounts?
Ready for more questions and answers? Turn to “An
Interview with Annis Hapkiewicz, 2005 Award Winner”. An interview
with each year’s James Bryant Conant Award for high school chemistry
teachers typically appears in the September issue. It provides a great model
and inspiration for teachers returning to the classroom and its demands.
Scharberg shares stories from presenters at the spring ACS symposium “Teaching
High School Chemistry as a Second Career”. One of the presenters mentions
the question “…why would one choose to teach?” There are
many interesting answers—what’s yours?
C&EN CLICs: A New JCE Online ResourceCLIC, the high school portion of JCE Online, has a new feature: C&EN CLICs. CLICs connects JCE readers to selected articles from the ACS publication Chemical & Engineering News. The feature editor, Kevin Cunningham, has extensive experience as a high school chemistry teacher. He reads each issue of C&EN and selects articles of interest to high school teachers and their students. He then creates a shorthand record that allows teachers who are short on time to quickly determine whether the article meets their interests and current classroom needs. A link in the record takes JCE subscribers directly to the article online. Thank you ACS for making these links available. See more details in News & Announcements. ACS Fall National Meeting—Washington DCHigh school teachers able to attend the ACS National Meeting in Washington DC (Aug. 27–Sep. 1) will find many of the planned symposia directly useful in their classrooms. For example, teachers will hear many exciting ways to celebrate National Chemistry Week 2005 during the Wednesday afternoon symposium “TOYing with Chemistry—National Chemistry Week—Let’s Go!” Teachers interested in becoming more involved in research will want to drop in Wednesday morning at “New Frontiers at the Interface between High School and University Teachers”. For full symposia listings and a program schedule, please see the August
issue of JCE.
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