Indy's best: young scientists cross the finish line.

Just 2 weeks before race-car enthusiasts will flood Indianapolis for the Indy 500, thousands of high school students zoomed into the city for a more cerebral, yet also lucrative, competition. The 2006 Intel International Science and Engineering Fair (ISEF) offered some $4 million in scholarships, internships, science trips, and other prizes to a field of nearly 1,500 competitors.

The students, from 47 countries, created full-throttle experiments and inventions, and judges gave green flags to the most impressive ideas.

Setting the pace were the three winners of the Intel Foundation Young Scientist Award. The fair's top honors and $50,000 scholarships went to Madhavi Gavini of the Mississippi School for Mathematics & Science in Columbus, Meredith MacGregor of Fairview High School in Boulder, Colo., and Hannah Wolf of Parkland High School in Allentown, Pa.

Inspired by her grandmother, who practices holistic medicine called ayurveda, Gavini, 16, examined extracts of the herb Terminalia chebula, a relative of the walnut that has been used as an antiseptic. Gavini found that the substance kills the drug-resistant infectious bacterium Pseudomonas, which can be fatal to people with compromised immune systems. "No treatment on the market can do that," she says.

MacGregor, 17, discovered that both convection and air pressure produce the "brazil nut effect," in which shaking moves the largest particles in a container of granular materials to the top and the smallest to the bottom.

By measuring, photographing, and mapping zones of soft-sediment deformation, Wolf, 16, revealed sources and patterns of seismic activity within the Grand Staircase-Escalante National Monument in Utah.

Weeklong trips to the Stockholm Youth International Science Seminar and Nobel Prize Ceremonies in December went to three students: John Moore IV, 18, of Dayton Christian High School in Miamisburg, Ohio, for his creation of a fixed-wing micro air vehicle (MAV) and a flapping-wing MAV that carries a video camera; Shannon Babb, 18, of American Fork (Utah) High School, for a continuation of her research on a newly erupted sulfur spring; and Yi-Chi Chao, 18, of the Affiliated Senior High School of NTNU in Taiwan, for his work on orb-weaving spiders.

Thanks to their insights into how sleep deprivation, selective serotonin reuptake inhibitor antidepressants, and caffeine combine to influence long-term memory in fruit flies, Mary Douglas and Alison Liu, both 17, of Manhasset (New York) High School are headed to September's European Union Contest for Young Scientists in Stockholm.

The best-team-project award and a July trip to the European Youth Science Exhibition in Tarragona, Spain, went to Victor Shia, George Chen, and Frank Chuang, all 17, of Monta Vista High School in Cupertino, Calif. The young men designed a symmetric, 512-bit, block computer code that's simple and flexible.

The first-place finisher in each of the competition's science-topic categories received a $5,000 scholarship and an Intel laptop computer, while the schools and the fairs that these winners represented each received $1,000. Best-of-category winners included Wolf for earth science, Moore for engineering, Gavini for medicine and health, MacGregor for physics, and Chao for zoology. Other category awards went to Maya Wolpert, 18, of Hathaway Brown School in Shaker Heights, Ohio, for the behavioral and social sciences; Adrian Veres, 16, of College Jean-de-Brebeuf in Montreal for biochemistry; Caroline Lang, 14, of Independence Home School in Yardley, Pa., for botany; Chen Tsai, 16, of the Affiliated Senior High School of NKNU in Taiwan for chemistry; Maria Godinez, 16, of CBTis No. 139, San Francisco del Rincon in Mexico for computer science; Erica David, 16, of Pinedale (Wyoming) High School for environmental sciences; Michael Viscardi, 17, of Josan Academy in San Diego for mathematics; Andrew Warren, 16, of Lake Highland Preparatory School in Orlando, Fla., for microbiology; and Terik Daly, 16, of Oak Grove High School in San Jose, Calif., for space science.

"The Intel ISEF attracts the most talented young scientists in the world. It is impossible to come away from the Intel ISEF without renewed optimism for the future of science," says Elizabeth Marin-cola, president of Science Service, which publishes Science News and has organized ISEF since its inception in 1950.

Intel is the title sponsor of the competition and provides support along with other corporations, universities, organizations, and government agencies.

GROW FOR IT A newly discovered protein called oncomodulin prompts injured rat-nerve cells to regrow significantly farther (top) toward the right than did cells not getting the protein (bottom).

FAST TRACK Top honors at the science fair in Indianapolis went to (left to right) Hannah Wolf of Allentown, Pa., Madhavi Gavini of Starkville, Miss., and Meredith MacGregor of Boulder, Colo.