Science projects that use a cute switch, a tiny light bulb and a 12-volt battery to demonstrate electrical conductivity, or that require dropping Mentos in a Coke bottle to illustrate propulsion, won’t get you to first base here in the 21st century. Not by a long shot.

The project at the Intel Science Talent Search that came closest to the light bulb and battery effort of yore was titled “Facile, Single Step Conversion of Biomass to Electricity.”

It would be a ridiculous oversimplification to say it uses yeast to generate electricity.

“The electron mediator goes into the yeast and grabs the electrons, and they catalyze on the other side and pass through a reverse osmosis membrane that we need because [otherwise] the ions would fog up the membrane between the anode and cathode,” said Pavan N. Mehrotra, 18, of Simi Valley, Calif.

If his invention ever gets into production, “I’d like it to help power the [electrical] grid.”

An exhibit hall at the National Geographic Society’s downtown headquarters was filled with 39 other projects of a complexity that rivaled his own. Each came with a high school student eager to brief the people milling through the hall on the research involved, and each exhibit had a title that would baffle virtually anybody who lacks an advanced science degree.

“Polyoxovanadate-based Surfactants: The Search for an Effective Heterogeneous Catalyst” was among the shorter titles.

The projects on show in Washington are the end result of a competition among 1,712 high school seniors nationwide. The 40 finalists were competing for $630,000 from Intel. Each one of them will go home a winner, said Intel’s Lisa Malloy, with scholarships ranging from $7,500 to $100,000.

The crowd was a mix of anxious parents sizing up the competition and serious adult science wonks whose questions verged on cross-examination. This did not seem to faze the contestants.

“I built a predictor of exactly when one class of proteins will combine with another class of proteins,” explained Jonah Kallenbach, 17, a senior at Germantown Academy in Fort Washington, Pa. “We will be developing a new class of drugs which could target disordered proteins with ordered proteins.”

The notion of dealing with the “Interactions of Intrinsically Disordered Proteins” came to Kallenbach over the summer, though he said he has been interested in proteins since middle school.

Alexa Victoria Dantzler’s exhibit may have been drawing particular attention because its title contained five consecutive words to which a layman might relate: “Residues in Dry Cleaned Fabric.”

Those residues are a problem, or, at least, they might be, the senior from Bishop O’Connell High School in Arlington County explained.

The chemical perchloroethylene is the culprit, a toxic substance already banned by dry cleaners in Philadelphia and Germany, and soon to be banned in California, she said. After developing a new means of testing for the residue in dry-cleaned garments, she trundled around to 48 dry cleaners in the Washington area to have something cleaned.

Her test found no perc, as she calls it, in 71 percent of the test garments. But there was a notably measurable amount in 21 percent. She also found that the residue built up each time an item was cleaned.

Now she’s working on a test for “dermal absorption” to judge how much of that residue gets into the body. Does she suggest that people keep taking their clothes to dry cleaners who use perc?

“Until we know the dermal absorption, it’s hard to say,” Dantzler said. “Personally, I wouldn’t.”