"Flying dreams never lose weight, and the tension of scientific dreams is infinite". On the afternoon of March 23, the third "Tiangong class" was held as scheduled. On the 400 kilometer high orbit around the earth, Zhai Zhigang, commander of Shenzhou 13 crew, joined hands with astronauts Wang Yaping and ye Guangfu. In the nearly one hour teaching process, he not only demonstrated a variety of scientific experiments, but also answered the questions raised by students in the ground class by connecting heaven and earth. Through multiple channels and several new media platforms of China National Radio and television, the "Tiangong classroom" was broadcast live to the world at the same time. "Tiangong classroom" began on June 20, 2013. At that time, with the cooperation of astronauts Nie Haisheng and Zhang Xiaoguang, Wang Yaping, a member of the Shenzhou 10 crew, gave China's first space lecture in the Tiangong-1 space laboratory, demonstrated the unique physical phenomena in the weightless environment for more than 60 million primary and secondary school students, and conducted the interaction between heaven and earth. Since then, "Tiangong classroom" has become a well-known national brand for the popularization of scientific knowledge in China. With the successful launch of the Tianhe core module, China's Tiangong space station has entered the stage of on orbit construction, and the "Tiangong classroom" has become active. The three astronauts in the Shenzhou 13 crew opened classes successively in December 2021 and recently. They turned into well-trained science teachers, demonstrated a number of carefully designed scientific experiments to the global audience and revealed the scientific truth behind them in nine days, It has stimulated the enthusiasm of people all over the world, especially young friends, to explore scientific laws and the mysteries of the universe. In this process, China's science popularization has also reached a new height. The experiment is colorful Interaction is booming The mascot of the Beijing Winter Olympic Games, "ice pier pier" doll, did not fall and fall along the parabola direction, but gave people a sense of uniform motion along the straight line. A supersaturated solution is extruded from the bag along the short tube, forming a liquid ball at the end of the short tube, and then suspended in the air. When touched by a short rod, the liquid ball is like being enchanted, and soon the whole body "freezes" into an ice ball. Squeeze a little water on the two small plastic plates to form two small water balls, which are then gently approached. The two small water balls are integrated and a small liquid "bridge" several centimeters long is formed between the plastic plates. Vegetable oil and water blend and mix in a small bottle, but they can't separate themselves. Instead, tie one end with a rope and throw it up with your arm for a while. After that, water and oil are successfully separated The exciting moments of the third "Tiangong class" make many students think and aftertaste. Indeed, the phenomena demonstrated in the microgravity environment of these space stations are so different from those seen on the ground that they completely exceed the daily experience and perception. Many students are still thinking and pursuing the scientific truth behind them with interest. "After watching the live lecture, my child wrote a diary and asked several questions about space. I think this is the best diary he wrote. These days, he has been looking for information and answers. The space class really opened his eyes. Thank the astronauts and teachers on the Chinese space station!" One parent wrote on social media. "Tiangong classroom" is not a one-way explanation and demonstration of the experiment by teachers "from top to bottom", but a two-way interaction with questions and answers. Teacher Wang Yaping left questions to students: what kind of motion should be seen from the ground? Why does the liquid metal ball glow again in the cooling process? Netizens and students in the ground class asked the astronaut teacher a number of questions. For example, what is the feeling of tears in the space station? What research can the container less experimental cabinet of the space station be used for? The astronaut teacher gave detailed answers and explanations to these questions. "Tiangong" has its own flow Classroom design Looking at the three teaching activities that have been carried out, it is not difficult to find that the "Tiangong classroom" is carefully set, vivid and attractive, which shows the intention and professionalism of the organizers and implementers. "Tiangong classroom" is undoubtedly its own "flow", which is naturally attractive. However, if the selection and design of classroom teaching content, especially the selection of demonstration experiment, the teaching effect may be greatly reduced. It is understood that the teaching content of "Tiangong classroom" is to carefully select the contents and projects that are easy for astronauts to operate, easy to observe the experimental effect and have a great contrast with the ground effect on the premise of ensuring absolute safety. Therefore, people see that the "Tiangong classroom" presents some experiments related to object motion, liquid buoyancy, liquid surface tension and so on in the microgravity environment, which are deeply attracted by novel space phenomena such as "diving table tennis", the "super water polo" of the reflection portrait, and the "Chinese knot" attached to the water film. A good example of "effervescent film" is to add the teaching content of "effervescent film". The original idea of the experiment came from a question raised by a child. When screening, the parties concerned were worried that the gas emitted from the water ball might cause the liquid to splash on the devices in the cabin, so they did not include it. However, Wang Yaping thought the experiment was very creative and successful, so he demonstrated it in class, which was refreshing. Careful selection of teaching tools is a major feature of "Tiangong classroom". In the 23 day's teaching, the "Star" ice pier pier flashes on the Beijing Winter Olympic Games. Wang Yaping and Ye Guangfu carry out parabolic experiments in space by throwing ice dolls and dolls together. It is understood that the ice pier dolls are one of the "blind boxes" sent by the manned spaceflight team when they embark on the spaceflight crew. Many people were impressed by the origami flowers in full bloom in last year's "Tiangong classroom" water film tension experiment. It was specially made for the experiment by Wang Yaping and his daughter. It was a colorful and affectionate flower of "science and technology". At the "Tiangong classroom" on the 23rd, it was also noted that when introducing the high and micro gravity experimental cabinet, the astronaut teacher showed the video data of the previous experiment, which further expanded and enriched the classroom teaching content. It is understood that teaching activities through experimental videos will become one of the development directions of "Tiangong classroom". Work together to build Promote development and evolution "Tiangong classroom" is a national brand of popular science education jointly created 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 Corporation, with the support of the China Science and Technology Museum and relevant research and test units of manned space engineering. Its success is achieved through the joint efforts of all parties. Tiangong-1 space laboratory and Tiangong space station are prerequisites for space teaching and science popularization. According to the "three-step" development strategy, China's manned space engineering has made a historic breakthrough, and its eight major systems, including astronauts, space applications, manned spacecraft, launch vehicles, launch sites, TT & C communications, landing sites and space laboratories, have made major achievements. At the end of 2011, the China Association for science and technology proposed to the China Manned Space Engineering office that astronauts teach science courses to teenagers in space by taking the launch of Shenzhou 10 and docking with Tiangong 1 as an opportunity. This proposal received a positive response from the China manned space office. After the successful completion of the rendezvous and docking mission between Shenzhou 10 and Tiangong 1, the "Tiangong classroom" opened for the first time. "Tiangong classroom" develops and evolves with the progress of manned spaceflight technology. It was found that compared with the first class, the pictures of the last two live broadcasts of "Tiangong classroom" were clearer and the sound delay was significantly reduced. This is due to the development of the relay communication satellite that undertakes the data transmission between heaven and earth, namely TIANLIAN satellite. TIANLIAN satellite has developed from three satellites of the first generation a few years ago to five satellites at present, and the second generation 01 satellite has been successfully launched. The data transmission capacity and stability of "TIANLIAN" have been greatly enhanced, and the presentation effect of "Tiangong classroom" has been significantly improved. School students are the main objects of the "Tiangong classroom" service. Educational administrative departments at all levels and primary and secondary schools have taken action to mobilize and encourage students to participate in the "Tiangong classroom" through various ways and media through temporary curriculum adjustment and other measures. For example, the Ministry of Education released a prompt about watching "Tiangong classroom" on its official website two days in advance, predicting the opening time and teaching content. Local science and technology museums and other popular science institutions have also taken positive action to organize local primary and secondary school students to watch the "Tiangong classroom". Some also arrange scientific and technological experts in relevant fields to do pre class preview and post class Q & A for students according to the teaching content. It is worth mentioning that the "Tiangong classroom" has driven the popularity of science and popular science. Some scientific and technological experts spontaneously produced popular science video programs around the teaching content of the "Tiangong classroom" and widely disseminated them through our media. Expand ground class Focus on Cyberspace Through three lectures, people noticed that "Tiangong classroom" formed an interactive mode of "Tiangong + ground classroom", and the setting of ground classroom changed every time. For the first time, the ground class is arranged in the middle school affiliated to Renmin University of China in Beijing. During the second teaching, the ground classroom is further divided into ground main classroom and ground sub classroom. The former is arranged in the China Science and Technology Museum in Beijing, while the latter has four, respectively in Nanning, Guangxi, Wenchuan, Sichuan, Hong Kong and Macao. During the third lecture, the ground classroom used the main classroom and sub classroom. The position of the former remained unchanged and was still in the China Science and Technology Museum. The latter has two, respectively in Lhasa, Tibet and Urumqi, Xinjiang. The setting, adjustment and change of the ground sub classroom undoubtedly expanded the coverage of the "Tiangong classroom", allowing students in more places, including the Special Administrative Region, to have direct communication and interaction with astronauts and teachers, especially the opportunity to directly put forward their own scientific issues of concern to them. It is worth noting that while trying to expand the coverage of the ground classroom, the "Tiangong classroom" also focuses on the infinite and broad network world, pays attention to and responds to the questions raised by the majority of netizens. For example, in the third class, before answering the questions of students in the ground class, the astronauts first answered two questions raised by netizens, which will further stimulate netizens' enthusiasm to explore scientific knowledge. (Xinhua News Agency)