China News Service, Beijing, March 23 (Ma Shuisha and Guo Chaokai) At 15:44 on March 23, the second lesson of "Tiangong Classroom" was held at the Chinese Space Station. "Space teachers" Zhai Zhigang, Wang Yaping, Ye Guangfu gave another wonderful class space science class.

This is the third space lecture for Chinese astronauts and the second space lecture for the Shenzhou 13 astronaut crew.

  During the 45-minute lecture, Zhai Zhigang, Wang Yaping and Ye Guangfu cooperated with each other to vividly demonstrate the space "ice and snow" experiment, liquid bridge demonstration experiment, water-oil separation experiment, and space parabolic experiment in a microgravity environment, explaining the scientific principles behind the experimental phenomena in simple terms. , while showing some space science facilities and introducing the working and living conditions on the space station.

  On the ground, water and oil naturally stratify, with oil on top and water on the bottom, but on the space station it's very different.

In the water-oil separation experiment, after Wang Yaping shook a transparent bottle filled with water and oil, the water and oil did not naturally stratify in the weightless environment of space, but mixed together.

How to separate water and oil?

Ye Guangfu revealed the answer, and saw that he quickly rotated the bottle, acting as an "artificial centrifuge", which generated centrifugal force through the rotation, and the water and oil in the bottle were successfully layered.

  In the space parabolic experiment, Bing Dundun, the new "top-class" mascot of the Beijing Winter Olympics, made a surprise appearance as an "assistant".

I saw Wang Yaping threw the mascot Bing Dundun gently. It did not fall like it was on the ground, but moved forward at a constant speed along the direction it was thrown from.

This is the most intuitive manifestation of the microgravity environment of the space station, which vividly demonstrates the difference between the parabolas of heaven and earth.

  During the lecture, the astronauts interacted with teachers and students on the ground through video calls.

In the interaction between heaven and earth, when talking about whether the skin will get better in space, Wang Yaping said that because the space station has no sunlight, the temperature and humidity are also controlled within a suitable range. In addition, in a microgravity environment, human body fluids will be distributed upward, and the skin will It will also improve upwards, "so I feel that my skin is in good shape in the space station."

  This space class has a main ground classroom in the China Science and Technology Museum, and two ground sub-classes in Lhasa, Tibet and Urumqi, Xinjiang.

During the construction and operation of the space station, the "Tiangong Classroom" will continue to carry out space teaching activities, and conduct space science education in various forms and rich contents.

Platforms such as the Manned Space Engineering Network will continue to solicit creative suggestions on the "Tiangong Classroom", and all sectors of society, especially young people, are welcome to actively participate.