A Chinese astronaut orbiting 340 kilometers above Earth gave a live video lesson on gravity to school children in China on Thursday.
Wang Yaping, China's second female astronaut, is one of three crew members sent to space last week on the Shenzhou-10 spacecraft.
She delivered her lecture from the Tiangong-1 experimental space lab, which China views as a prototype for a full-fledged space station.
Wang participated in a question-and-answer session with students in a Beijing school. She also conducted a series of experiments demonstrating how objects react in zero gravity.
State media said more than 60 million students and teachers were expected to watch the lecture, which is the first of its kind for China.
Although it remains behind the U.S. and Russia, China's space program has made major breakthroughs in a relatively short time. In 2003, China sent its first astronaut to space. Five years later, it completed its first spacewalk.
Beijing views the latest 15-day mission, its longest ever, as an important step toward the building of a permanent space station, which China hopes to complete by 2020.
It is not involved in the International Space Station project, partly because of objections from Washington, where many view Beijing's military-backed space program with suspicion.