The fourth "Tiangong Classroom" set up five sub classes in Beijing, Inner Mongolia, Anhui, Zhejiang, and Shaanxi. At 15:48 Beijing time on September 21, 2023, the fourth lesson of "Tiangong Classroom" began on the Chinese space station. Newly appointed "space teachers" Jing Haipeng, Zhu Yangzhu, and Gui Haichao brought a wonderful space science popularization lesson to young people. This is the first time that Chinese astronauts have taught in the Mengtian Experimental Module. During the approximately 48 minute lecture, astronauts Jing Haipeng, Zhu Yangzhu, and Gui Haichao from Shenzhou 16 vividly presented the working and living scenes of the space station's Mengtian experimental module, demonstrating the spherical flame experiment, the wonderful "ping-pong ball" experiment, the momentum conservation experiment, and the "see again gyroscope experiment", and vividly explaining the scientific principles behind the experiment. During the teaching period, astronauts had real-time interactive communication with teachers and students in the ground classroom through video calls. This teaching activity has set up 5 ground classrooms in Beijing, Alxa League in Inner Mongolia, Yan'an in Shaanxi, Tongcheng in Anhui, and Ningbo in Zhejiang, with approximately 2800 student representatives participating in the on-site activities. The Central Radio and Television Station conducted a live broadcast throughout the entire process. The teaching activities are jointly organized by the China Manned Space Engineering Office, the Ministry of Education, the Ministry of Science and Technology, the China Association for Science and Technology, and the Central Radio and Television Administration, with support from research and testing units related to manned space engineering. During the application and development phase of the space station, "Tiangong Classroom" will continue to carry out space teaching activities. The China Manned Space Engineering Office will continue to widely solicit ideas and suggestions on the "Tiangong Classroom" through platforms such as the media, "Learning Power", and the official website of manned space engineering. We welcome the active participation of all sectors of society, especially young people. (New News Agency)