Guangming Daily reporter Zhang Wen Guangming Daily correspondent Zhan Kang
March 23 was the 159th day of the shenzhou 13 crew astronauts Zhai Zhigang, Wang Yaping and Ye Guangfu in orbit. On the way back, three astronauts taught the second lesson of the "Tiangong Classroom" to the teenagers on the China Space Station. The main ground classroom is located in the China Science and Technology Museum, and the sub-classes are located in Lhasa, Tibet and Urumqi, Xinjiang. In the afternoon of the same day, the reporter walked into the China Science and Technology Museum and listened to this wonderful space science lesson with the teenagers in the main classroom on the ground.
At 15:44, the "Tiangong Classroom" officially opened.
On March 23, students listened to the "Tiangong Classroom" in the main classroom on the ground of the China Science and Technology Museum. Guangming Daily reporter Zhang Wen photo / Guangming pictures
On March 23, at the No. 70 Middle School in Urumqi, Xinjiang, students watched the second lesson of the "Tiangong Classroom" while conducting water and oil separation experiments. Xinhua News Agency
"Space exploration is endless, hello everyone, I am 'space teacher' Wang Yaping, very happy that we have met again, today is the second lesson of our 'Tiangong Classroom'..." "I am The commander Zhai Zhigang, continue to take on the filming work." "I am astronaut Ye Guangfu, and I am very happy to be able to share the scientific knowledge in space with you again."
A familiar voice sounded, and the figure of the "Space Teacher Team" appeared in the "Tiangong Classroom" again, immediately "bringing" the students into the wonderful space.
Lens one is doing "ice and snow" experiments on the Chinese space station
Not long ago, the Beijing 2022 Winter Olympics and Paralympic Winter Games let people appreciate the charm of ice and snow sports. "Space Teacher" Wang Yaping first showed the space "ice and snow" experiment. Only to see her take out a transparent bag containing a saturated sodium acetate solution, with a straw attached to the mouth of the bag. She then carefully squeezed the solution out of the bag, and after several attempts, a transparent ball of liquid gradually formed at the mouth of the straw. "It's about to be the time to witness a miracle." Wang Yaping gently touched the sphere with the hair root that had been dipped in the crystal nucleus in advance, as if by magic, and the transparent ball quickly turned into a crystal ball, looking like an "ice ball".
"Sodium acetate solution has a very large solubility in water with higher temperatures, and it is easy to form a supersaturated solution, in which as long as there is a little crystalline nuclear particle, it can break its steady state and precipitate a large number of crystals." Wang Yaping revealed the mystery, and when the crystals are precipitated, heat is also released, so this "ice ball" feels hot to the touch.
Inside the space station, the surface tension of the liquid in the microgravity environment causes the extruded liquid to form a full and uniform liquid ball. In order to show the surface tension more intuitively to the students, Wang Yaping then did a second experiment. I saw that she was holding two plastic plates in her hand, and Ye Guangfu was holding a bag containing drinking water and squeezing a water ball on the surface of the two plastic plates. At the same time, the students in the main classroom on the ground are doing the same experiment. Wang Yaping leaned the two water balls together until they melted, and then slowly pulled them apart, a strange liquid bridge was built.
At the ground main classroom site, the reporter observed that the same phenomenon did not appear in the hands of the students. Chen Zheng, a member of the "Tiangong Classroom" teaching expert group and an associate professor at Beijing Jiaotong University, told reporters that the liquid bridge is formed by the water connecting two plastic plates under the action of surface tension. In the microgravity environment of the space station, water can form a liquid bridge with a little surface tension. There are gravity factors on the ground, which need to be achieved by using conditions such as high pressure, and the experimental principles of the two are not the same.
Scene 2 "Ice Pier" unveiled in "Tiangong Classroom"
In the subsequent buoyancy experiment in space, Wang Yaping encountered a "problem". Seen on the screen, she is holding a small bottle containing two liquids, transparent water and yellow cooking oil. After Wang Yaping and the students shook and sat the bottles in their hands together, a completely different phenomenon appeared in the Heaven and Earth Classroom: the liquid in the bottles in the students' hands gradually formed layers, while the water and oil in Wang Yaping's bottles were still mixed together.
What to do? Wang Yaping asked the students in the ground classroom for help. A classmate proposed to use a rotation method to separate water and oil by centrifugation. "Artificial centrifuge" Ye Guangfu immediately demonstrated, only to see him tie the rope to the mouth of the bottle, quickly rotate the bottle, and in a short while, the water and oil mixture in the bottle was layered.
After showing the wonderful liquid phenomenon in space, Wang Yaping began to carry out the last experiment - space projectiles. At this time, a small and cute Beijing 2022 Winter Olympics mascot "Ice Pier" appeared in the "Tiangong Classroom". It is understood that this top-notch "teaching assistant" was stationed on the Chinese space station last year with the Shenzhou 13 crew.
Only to see Wang Yaping gently push with his fingers, the "ice pier" slowly drifted straight to Ye Guangfu not far away. After Ye Guangfu caught it, he pushed it towards Wang Yaping, and the "ice pier" made a nearly uniform linear movement back and forth between the two of them.
"Flat throwing motion refers to the movement of throwing an object at a horizontal initial velocity and subjected to gravity without regard to air resistance." Zhang Jian, the main classroom teacher of the "Tiangong Classroom" ground and a physics teacher at the Second Affiliated Middle School of Beijing Normal University, told reporters, "The 'ice pier' can do nearly uniform linear motion on the space station because in the microgravity environment of the space station, the object is almost unaffected by gravity." ”
Shot 3 The "Space Teaching Aids" science experiment cabinet debuted
After the interesting experimental demonstration, two cool scientific experiment cabinets on the Chinese space station - high-micro gravity experimental cabinet and containerless material experimental cabinet debuted, through the on-site introduction and experimental video playback, the "space teachers" used the "space teaching aids" experimental cabinet to visually display the progress of space science in this mission.
"Scientific experiments are an important means to help scientific research, scientific experiment cabinets are the main facilities for us to carry out scientific experiments on the space station, and after the Launch of the Wentian Experimental Module and the Dream Experiment Module into orbit, more experimental cabinets will be added to carry out more scientific experiment projects." Zhang Wei, director of the Application Development Center of the Space Application Engineering and Technology Center of the Chinese Academy of Sciences, said that there are more than a dozen scientific experiment cabinets such as life science experiment cabinets and microgravity fluid physics experiment cabinets in the Chinese space station, which will support large-scale scientific experiments in the future.
"At that time, Chinese and foreign scientists can rely on experimental cabinets to carry out research, and our Chinese space station will become a space science platform that benefits all mankind." Ye Guangfu said, "Students, we are also eagerly looking forward to your own scientific experimental ideas, maybe the next time we will show your experimental project in space." ”
The four shots interact with the heavens and the earth, and the excitement continues
Space experiments are unending, and the wonderful interaction between heaven and earth continues.
"Do tears on the space station stretch long out of the corners of the eyes like jelly or will they jump out and float up one by one?"
"Is the moon seen on the space station the same as what is seen on Earth?"
"Can water in space boil?"
"How do you become a scientist who goes to the space station to do experiments?"
…………
In the interactive session of heaven and earth, netizens and students in the ground class threw out many interesting questions, and the 3 astronauts patiently answered in detail.
Wang Yaping shared with the students the feeling of tears on the space station: "Flying in the space station for so long, we have also experienced many emotional and even tearful moments. But the tears can't flow down as naturally as they do on the ground, but swirl in the eye sockets, or in the corners of the eyes. So it may be hard to hold back tears on the ground and pretend to be strong, but it's easy to do it in space. ”
Ye Guangfu even encouraged the students to go to the space station to do experiments in the future, and they could also submit their experimental projects to the space station and then operate remotely on the ground. He said: "Students, all you have to do now is to study hard, exercise well, be brave to chase your dreams, and believe that everything is possible in the future." ”
Soon, it was time to say goodbye, and the 3 astronauts sent their blessings and expectations to the students.
Zhai Zhigang said: "Students, the future belongs to you! ”
"Exploring the vast universe, developing the space industry, and building a space power are our unremitting pursuit of the space dream." I hope that the students will only strive for the day, live up to Shaohua, and move forward firmly on the road of pursuing their dreams! Ye Guangfu said.
Wang Yaping said: "The flying dream never loses weight, and the tension of the scientific dream is infinite. I hope that the students will continue to work hard to learn scientific knowledge, improve scientific literacy, explore the mysteries of science, and the future space station will be built by you! ”
After class, Xu Yihang, a student at Beijing Middle School, told reporters that he was very happy to use the physics knowledge he learned to help "space teachers" solve the problem of water and oil separation. "This exchange with the astronauts was very memorable for me and ignited my scientific dreams. I am extremely proud and proud of the development of China's aerospace industry! Xu Yihang said emotionally.
The stars are vast and the exploration is endless. Just as the astronauts' blessings, flying dreams and scientific dreams will lead the dreams of more teenagers, inspire them to explore the unknown, plant the seeds of scientific thinking, take root and sprout...
Guangming Daily (2022-03-24 08 edition)
Source: Guangming Network - Guangming Daily