Former science television personality Bill Nye hosted a live online video stream of the experiments on Thursday.
It marked the culmination of the YouTube Space Lab competition that challenged kids to design a science experiment to be conducted by astronauts 250 miles above Earth.
Dorothy Chen and Sara Ma were named winners in March in the 14- to 16-year-old age group. The Troy High School students' experiment asks the question: "Could alien superbugs cure disease on Earth?" Amr Mohamed from Egypt won the 17- to 18-year-old age group for an experiment about spiders.
YouTube, Lenovo and private space exploration company Space Adventures organized the competition.