Kiara Nirghin was leafing through a newspaper one day when she noticed several stories about farmers struggling with drought. Nirghin, a high school junior in Johannesburg, had known South Africa was in the midst of an intense drought, but in that moment she realized the problem extended far beyond her country: “It's affecting the whole world. And to this point, there hasn't been something that has revolutionized drought.”

Nirghin set about brainstorming on how to ensure that crops have access to water—even during the most severe stretches of dry weather. Her simple solution earned her the grand prize at the Google Science Fair in September. (Scientific American co-sponsors the awards.)

For her project, Nirghin created a biodegradable and superabsorbent material that can be “planted” alongside crops to create “mini reservoirs of water in the soil,” she explained in her presentation. First she boiled orange peels in water to produce a liquid rich in pectin, a highly absorbent carbohydrate. Then she combined the pectin with pieces of dried orange peels and avocado skins, baked the mixture to remove moisture and crushed it all into a powder. Finally, she mixed the powder with more peels and skins. The resulting polymer could hold 300 times its weight in water. In tests, the invention kept soil moist—and plants grown with it were taller and healthier and produced more flowers.

Nirghin hopes her material will help drought-stricken communities improve their food security. “Nirghin's project was inspiring for the judges,” says Mariette DiChristina, Scientific American editor in chief and chief judge of the Google fair since its inception in 2011. “They were impressed with her excellence of method, the project's capacity for impact and her passion for improving the world through science.”