The third lesson of "Tiangong Classroom" is scheduled to start at 15:45 p.m. on October 12. Astronauts Chen Dong, Liu Yang and Cai Xuzhe of the Shenzhou 14 flight crew will give lectures in space to young people, and CCTV will broadcast live to the world. The space teaching activity will continue to be conducted in the way of interaction between heaven and earth. Three astronauts will introduce and display the working and living scenes of the China Space Station Sky Quest Laboratory Module on orbit, demonstrate the capillary effect experiment in microgravity environment, the experiment of water polo becoming "lazy", the space interesting drinking water, the wrench that can turn around, and the introduction of plant growth research projects, and interact with the ground classroom (the introduction of the teaching content is attached), It aims to spread and popularize the knowledge of manned space flight and stimulate the interest of young people in science. Since the launch of the "Tiangong Classroom", two space lectures have been successfully held, and good social response has been achieved. In the early stage of the course content collection activity, all sectors of the society, especially the majority of young people, actively offered advice and suggestions through the news media, the "learning power" platform and the manned space engineering official website. Many good creative designs have come to the fore, and will continue to be displayed in this lecture and subsequent activities. Chinese astronauts sincerely invite young people to try to carry out relevant experiments on the ground synchronously, so as to perceive the mysteries of the universe and experience the fun of exploration from the differences between heaven and earth. (Liu Xinshe)