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February 25, 2008
Volume 86, Number 08
p. 56

School Buzzers

College students often get a buzz out of the many extracurricular activities available to them. But one university has decided that a device similar to a game show buzzer can enliven those endlessly long???and dare we say boring????SCIENCE LECTURE CLASSES.

Buzzers: Enlivening large lecture classes.

Within three years, the University of Edinburgh plans to give every student a handset that allows professors to pose multiple-choice questions to up to 400 students at a time. Students can beam their answers via the remote units, and software quickly calculates the percentage of correct answers. The system is already being used in the school's science lecture halls.

The system provides a buzz that no cup of coffee alone can deliver. Simon Bates, a physics teaching coordinator, tells Scotland's national newspaper, the Scotsman, that the device "keeps students engaged by breaking the monotony of listening to someone talk for 50 minutes."

Use of the device assures students, in an anonymous way, that others in the class may not understand a particular topic. Misery loves company.

The buzzers are a wake-up call for teachers, too, since they provide instant feedback to the lecturer, who can adjust presentation materials on the fly as he or she discovers whether the course material makes sense to the large majority of students.

The updated system, to include all the school's large lecture classes, will require handsets likely to cost as much as $50 each. That's not a significant cost, says the school's dean of learning and teaching for science and engineering. "It is affordable compared to a textbook," he tells the newspaper.

Fingerprinting Diamonds

For 19th-century poet Emily Dickinson, hope is the thing with feathers that perches in the soul. For humorist Woody Allen, the thing with feathers isn't hope at all but his nephew in dire need of a psychologist. However, there is no mistaking the HOPE DIAMOND. It is truly unique.

Smithsonian Institution
Hope Diamond: Red Phosphorescent ID.

Shine a white light on the Hope Diamond and the brilliant blue gem will dazzle you. Shine an ultraviolet (UV) light on the distinguished gem and it will glow red-orange for about five minutes. A research team from the U.S. Naval Research Laboratory, the Smithsonian Institution, and Pennsylvania State University says the phosphorescent property of blue diamonds can distinguish synthetic and altered diamonds from the real thing.

They teased out these facts and more by wheeling in a portable spectroscope to examine the 45.52-carat Hope Diamond on display at the Smithsonian's National Museum of Natural History. Scientists had to do their work in the morning and evening while the museum was closed. The diamond is one of the museum's most popular exhibits.

Blue diamonds, like the Hope Diamond, emit light even after the UV source is extinguished, the scientists found. However, other colors of diamonds do not phosphoresce, but instead fluoresce, emitting only as long as the stone is illuminated with UV radiation.

And all blue diamonds have a red phosphorescent component that is unique to each, say the scientists in the January issue of Geology (2008, 36, 83). Spectroscopic analysis of the red phosphorescent component allows scientists to individually identify each blue diamond.

Natural blue diamonds have boron impurities that make diamonds appear blue under natural light, the scientists say. Under UV light, high levels of boron and low levels of nitrogen impurities cause blue diamonds to phosphoresce.

Penn State scientist Peter J. Heaney is interested in spectroscopic methods to "fingerprint" diamonds. The technique could be an adjunct to the current Kimberly Process Certification Scheme, a not entirely successful effort by the diamond industry to combat trade in diamonds used to finance African conflicts.

This week's column was written by Marc S. Reisch. Please send comments and suggestions to newscripts@acs.org

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Chemical & Engineering News
ISSN 0009-2347
Copyright © 2009 American Chemical Society


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