Chinese astronauts conducted a science lecture to millions of students on Dec. 9,2021 from the Tiangong space station. The three astronauts, Hai Zhigang, Wang Yaping and Ye Guangfu, showed life in space and conducted experiments in microgravity.
It was the first lecture of the Tiangong Class, China's first extraterrestrial（地球外的）lecture series. Its goal is to popularize space science.
"The laboratory of the space station has many conditions that the Earth laboratory does not have, such as the environment of weightlessness and radiation," said Wen Xin, a professor at Nanjing University of Aeronautics and Astronautics. He said that important jobs for astronauts in the space station include cell observation and maintaining plant life.
In the lecture, Ye demonstrated experiments related to cell growth in a weightless environment. He compared the growth and shape of cells in artificial gravity and zero-gravity to study their changing principles in space.
Another experiment in the space lecture was shown by Wang Yaping. She illustrated how a paper flower "bloomed" on the surface of water in Tiangong space station. She explained that the surface tension of water is magnified（放大）in space due to zero gravity.
One of the examples of surface tension on Earth is that some insects can "walk" on water. They use surface tension to "stand" instead of falling through water.
Surface tension plays a key role in product development. Researchers around the world are measuring surface tension to improve the quality of their products, according to Biolin Scientific, a science company. Paints are tailored to stick better on the surfaces they are applied to. Surface tension also has impacts in drug development.
Although the astronauts are thousands of miles away, their research does influence our life. Shi Yi, a teacher at the Beijing No. 101 Middle School, told China Daily that the space lecture was "an eye-opening experience that would arouse students' interest in science".
