Blackberries Power Chemistry Class

What do blackberries have to do with math? Sophomore chemistry students at Ridgewood High School learned that fruits like blackberries can power their math lessons—or at least their calculators.

With help from teachers Dr. Lillian Labowsky and James Tuohey-Kay, regular chemistry students have powered calculators using nanocrystalline solar cells.

All sophomores are required to take the subject, but often, "Students are turned off to chemistry, but we really want to generate interest... One student's mother told me he now says his future is in nanotechnology," Labowsky said.

The calculator project combines a skill learned in biology—slide construction—with chemistry fundamentals, while remaining safe and engaging. "We started to look at this project, and as it turned out, it's one of the hottest areas out there," said Labowsky, a converted university professor who studied under Nobel Prize winner John Bennett Fenn.

Entirely funded by the National Science Foundation—which purchased a new chemistry oven for the school—the project pits two graduate fellows from the Stevens Institute of Technology with the high school students. While Tuohey-Kay and Labowsky's classes help with experiments, the fellows also gain teaching experience.

Doctoral candidates Huang Tang and Ishan Wathuthanthri study nanotechnology, and the Ridgewood class used their expertise to build a solar-powered calculator.

The class constructed two slides that, when influenced by a light source, could power the calculator. On the first slide, the white powder titanium oxide (not too different from a powdered doughnut) is baked onto the glass and coated with a plant's dye.

To gain a counter charge, carbon soot and an iodine solution are used on the other slide. Combined with the first slide, the substances will power the calculators when a light source is introduced, in this case an overhead projector.

The class needs four slides to power a calculator. Tuohey-Kay said two should be enough, but it's tough to get the maximum potential out of a slide.

Despite using several different combinations of blueberries, raspberries, cranberries, pomegranate, red cabbage and poinsettias, blackberries proved to be the most potent specimen. Tuohey-Kay said that isn't surprising, as the darker fruit absorbs more light from the sun.

The sophomores meet at least once a week during lunchtime, and 10 seniors help the underclassmen with the project. Although Tuohey-Kay and Labowsky executed some of the more technical tasks, the class "got pretty good at producing the slide," Tuohey-Kay said.

Seniors Nick Francis and Derek Loren handle procedure and aid sophomores when difficulties arise.

"The object is to get the most energy out of the slide," Francis said. "This is a great experience in building a solar cell. Everyone says solar technology is the future, but it's good to see it ourselves."

Loren highlighted solar energy for being "environmentally-friendly, made with cheap chemicals that aren't harmful. Solar has a big upside."

Both seniors look to go into different engineering fields—Francis, mechanical; and Loren, civil.

Students will present their project at Super Science Saturday March 6. For that presentation, some students will produce a video over the February break next week to illustrate the process. After Super Science Saturday, some seniors may continue research on the project.

Nanotechnology employing solar energy is already available for consumers, if only on a novelty basis, Tuohey-Kay said. People can buy tennis bags or backpacks that will charge their iPods or cell phones in the sun, as highlighted by a recent New York Times article.

Larger scale projects involving medical devices or cells woven into fiber are expensive and a little ways off, but are in the works.