Temptation to learn

The 1982 vintage of Lafite-Rothschild is among the most storied wines of the last few decades. To the serious collector, it is worth several thousand dollars a bottle, Robert J. Levis explained to his listeners.

Unless, of course, something goes wrong with the cork, and the precious fluid turns to vinegar. But how to tell without popping the cork?

The question was a hypothetical one - and not just because Levis didn't have a bottle of the fine bordeaux on hand. Most of his audience wouldn't be allowed to drink it anyway.

Levis is chairman of the chemistry department at Temple University, and the Rothschild conundrum was an extra-credit question in his new class for non-science majors: the Chemistry of Wine.

At many schools, there is a long tradition of watered-down science courses - heavy on memorization and low on true understanding - for students who seek merely to fulfill a graduation requirement. Physics for Poets, say, or Rocks for Jocks.

That's not the goal in Temple's Beury Hall.

Levis and his colleague David Dalton want their charges to grasp the why and how of science - to ask their own critical questions and devise a way to find answers. And if the students were attracted to the course by its nontraditional topic, that's OK.

"The price for that is they have to learn the chemistry behind it," Levis says.

Such efforts to boost scientific literacy are afoot elsewhere. The University of California at Berkeley, for example, offers a rigorous course called "Physics for Future Presidents," in which students must demonstrate their mastery of concepts by writing essays.

But education experts say the push needs to start well before college. Last week, it was announced that the performance of American students on the most recent international science test had declined. And researchers have found many students do not retain what they've learned, says Sarah Miller, codirector of the Wisconsin Program for Scientific Teaching, at the University of Wisconsin in Madison.

Some fault could lie with the instruction, she says - particularly in cases when science is presented "as this known quantity of information that must be memorized, which is the antithesis of the scientific endeavor."

How to answer one of the questions in the Temple chemistry class, on the other hand, was an unknown quantity.

Students were instructed to take several plastic bottles and fill them partway with grape juice, then add yeast. The goal: to measure how much carbon dioxide was produced as the sugary juice was being converted into alcohol.

The teachers suggested that the gas be trapped in a balloon, but after that the students were on their own. Most decided to submerge the balloons in water, correctly reasoning that the volume of gas would be equal to the volume of the water displaced, Dalton says.

But that process was not entirely straightforward. The students could not simply turn their balloons upside down to dunk them in water, as the fermenting juice would spill into the balloon.

Most solved this problem by pinching the neck of the balloon each time before submerging it.

A few others approximated the volume by assuming the balloon was roughly the shape of a sphere, Dalton says.

Then they measured the circumference with a string and used that to calculate the volume.

No matter the method, the volume had to be measured several times over the course of the experiment, in order to see how the rate of the reaction varied with temperature.

"The concept is that there is an experimental approach to many things that young men and women can use to engage their intellect," says Dalton, whose sense of humor can be as dry as a glass of chianti.

Lectures are part of the course, too, but they are not of the traditional stand-behind-the-podium variety.

In one recent class, Levis bounded up the stairs of the auditorium to illustrate how red wine gets its color. He was pretending to be a molecule of a pigment called malvidin, which jumps to a higher energy level (a higher "stair") when struck by light.

The molecule absorbs some of the light, from the blue-green end of the spectrum, whereas the color red passes through. So that's the only color we see.

Levis, a serious wine buff who makes wine in his garage, carried a ball of tinfoil in his hands as he leapt up the stairs. The ball represented a unit of light called a photon, which is emitted when the molecule goes back to a lower energy level. So when Levis jumped back down to a lower stair, he "emitted" the ball, tossing it at student Paige Gilbert. She was unfazed.

"He's very animated," she said of Levis afterward. "It didn't surprise me at all."

The same day, Levis posed his query on the 1982 Lafite-Rothschild. Without opening the wine, he asked, how can a prospective buyer be sure it hasn't gone bad?

He told the students that the answer involved nuclear magnetic resonance, the same concept used in an MRI machine. To earn extra credit, they'd have to do some research and write an explanation of just how that could be done.

(A partial answer: When placed in the magnetic field of a nuclear magnetic resonance spectrometer, vinegar and alcohol will absorb radiofrequency waves differently. That is, each has its own spectrum.)

While Levis doesn't mind if his students develop an appreciation for his favorite beverage (once they come of age), he stresses that alcohol must not be consumed recklessly. Indeed, four students chose to do their final presentations on how alcohol impairs the brain.

Besides the immediate reward of knowledge, the class comes with another benefit down the road - drinking the class project.

Sitting at the front of the lecture hall are two five-gallon bottles of fermenting liquid - one a Riesling, the other a Chateauneuf du Pape blend. The juice came from Procacci Bros., a Philadelphia purveyor of wine grapes.

Levis says the end result will taste more like an educational exercise than a fine wine.

Still, at a reception more than three years from now, the professors and their students - provided they are of age - will raise a glass.

Perhaps someone will make a toast to scientific literacy.