Teen scientists turn weeds into crop food and algae into clean water — and South Africa noticed

Rudra Patel is in Grade 11, and she's already inventing fertilizer. Her project turns extracts from invasive alien plants into biostimulants that feed crops — good enough to win the top senior prize of R75,000 (about $4,600) at the 2026 Eskom Expo International Science Fair. The junior crown went to Grade 8 learner Denica Swartz, who found that a lactic acid treatment cut chlorophyll-a — the green gunk of algae — in pond water by 77.92%. The four-day fair at Birchwood Hotel drew young scientists from South Africa, Tunisia, Ghana, Russia, Brazil, China, Turkey and Namibia. The problems on the table were local and real: weeds, dirty water, struggling crops. The solvers were schoolchildren.