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Jumping Bean Bounces Back : C'mon--you remember the fun of holding one in your hand. Now the little curiosities are hot once again.

September 11, 1994|BENJAMIN EPSTEIN | SPECIAL TO THE TIMES

In chaos theory, past observations enable the observer to make short-term predictions.

"Any time you're below this magic 62 degrees, the beans jump chaotically," Kriebel said. "If you know the pattern, you could amaze your friends by predicting the next movement."

That type of amazement is what he hopes will lead the beans to do no less than revolutionize the field of education. It is a field that he and a group of fellow New York scientists see as increasingly geared toward preparing students for the SATs and little else.

"I teach at a medical school, and over the last 25 years, I've seen a real fall-off in general-interest biology," Kriebel said. "Many students have not had hands-on experience with something alive. Instead, there is a fascination with computers, as if computers will ask and solve problems. All the teachers try to do now is teach for the SATs. There's a lack of real-world activities, and we're heading toward a monoculture."

Kriebel and his colleagues began to look for hands-on activities that would combine various disciplines such as math, biology and physics. Using piles of popcorn to monitor earthquake phenomenon was one. The jumping beans, which exhibit circadian rhythms and are sensitive to temperature and vibrations, were another, and results of experiments could be easily replicated.

With the help of Science Kit and Boreal Laboratories in Tonawanda, N.Y., the scientists hope to see their educational project introduced in high schools and colleges by next year.

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The bean made its jump to the United States from Mexico with a big push from Clement, the primary importer.

"Back in the early '60s, my husband was a traveling candy wholesaler," Clement said. "One day he came home with jumping beans and said he wanted to start selling them. I told him he had rocks in his head. I'd grown up with them in the Texas Panhandle, and I didn't see people spending money for them. The next year we were in business. It's a very odd business, to say the least."

Indeed. Because the jumping bean is both animal and vegetable, it's fraught with a unique set of problems.

It's an insect, so the population will fluctuate like any population. It's a crop, so it's weather dependent: If there's too little rain or if rain doesn't come at the proper time, the shrubs don't bloom--and for Clement, that's crop failure.

"Jumping beans are always popular, but we've lost customers because we can't guarantee our ability to ship every year," she admitted.

The beans are harvested from the desert floor and shipped by Clement to the United States. They are also sold unpackaged as a curio along the border, but in Mexico itself, the jumping beans are less of a novelty.

Away from Mexico, even delivery of the beans can cause excitement. A United Parcel Service driver abandoned his truck when he decided he was carrying a rattlesnake; explosives experts were called in and a building evacuated when a shipment passing through O'Hare Airport was thought to be a ticking bomb.

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Jumping beans don't bite or explode, but they have their share of other quirks.

Light makes the pod snap back and forth. Put it on a hot plate, it'll jump real fast. In nature, the pod's ability to jump may allow it to move off a hot rock or away from hot sand into the shade. "If the pod were to sit in direct sunlight, it could roast the larva inside," Kriebel said.

The pod has one rounded surface and two flat surfaces, joined at a 120-degree knife-edge--a common packaging angle found in nature. The larva crawls about inside the pod, weighting it asymmetrically.

Kriebel calls the "crochet hooks" on the caterpillar's legs the "original Velcro system." The larva can make the pod jump by jack-knifing its body and snapping it back and forth; it anchors its rear end with the hooks, stretches, bends over backward, contracts and releases. Not unlike a rubber band.

The larva is about a third lipid (a nice word for fat), a third water and a third protein. The lipid is converted into carbohydrate, the carbohydrate into an energy source.

"Given the amount of lipid, we've calculated that the beans have the capability of doing about a million jumps," Kriebel said. "But they turn into moths before that happens."

In fact, the larva jumps about 500,000 times before it pupates into a chrysalis. In a cool room, the larva will jump from August to December. In a refrigerator it can remain in the larval stage until spring.

"Put them in a refrigerator, take them out in January and they'll still be jumping," Kriebel said. "You've slowed down their clock."

Before metamorphosis, the larva makes a one-millimeter escape hatch in the shell wall. After its transformation, the adult moth pushes through the hole, abdomen first, and flies away in hopes of beginning a new generation of jumping beans. Clement believes that only the strongest survive the process, while Kriebel believes that most of the larva turn into moths.

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