Complete success!”Tiangong Classroom” second lesson full of dry goods

2022-04-25 0 By

Astronauts Zhai Zhigang (C), Wang Yaping (R) and Ye Guangfu (R) of the Shenzhou 13 mission give lectures at the China Space Station in Beijing, capital of China, March 23, 2019.When sending (xinhua xu had taken) on the afternoon of March 23,, “tiangong” classroom lesson two station began in China, the shenzhou number 13 crew astronaut zhai zhigang, ya-ping wang, Ye Guangfu interaction teaching, demonstrates the space orbit “ice” experiment and demonstration experiment, oil water separation, liquid bridge space parabolic experiment and a series of cool and fun.In the space “ice and snow” experiment, Wang Yaping made a “ice ball” with solution on the space station.The space “ice and snow” experiment is actually an anhydrous sodium acetate experiment on the space station.What’s the difference between doing this in space and doing it on the ground?Wei Hongxiang, a researcher of the Institute of Physics of the Chinese Academy of Sciences and director of the Committee of popular Science of the Physical Society, explained that there are two main differences.”The first one is the gravity environment. In the space station, it’s microgravity. In that environment, the crystallization is quite different from the ground.”Wei Hongxiang said.Then there is the container.The space “ice and snow” experiment on the space station has no container and is spherical, in which case crystals can develop outwards;If it’s in a container, because of the container, it can only crystallize inward.”In our space station, there is a material cabinet with or without containers. In fact, containers have a great influence on the growth of materials, because in the process of material growth, the shape of containers, surface crystallinity, surface roughness, lattice structure, defect, purity and so on have a great impact.”Wei Hongxiang said.Liquid bridge Demonstration Experiment In the liquid bridge demonstration experiment of Tiangong Classroom, water under the action of surface tension, builds a “bridge” between two plastic plates.”The liquid-bridge experiment taught in space shows very vividly the properties of surface tension of liquids.”‘There is no way to make a liquid bridge as big as the one in Tiangong on the ground,’ said Li Xiaotong, a teacher at Beijing No. 13 Middle School who teaches tiangong’s main ground class.Yes, there are differences between the liquid bridge experiment on the space station and the liquid bridge experiment on the ground.Chen Zheng, associate professor at Beijing Jiaotong University and a member of the Tiangong class expert group, explained that the liquid bridge experiment on the space station is a complete expression of surface tension, while the liquid bridge experiment on the ground introduces a new mechanism of dielectric polarization. Although the phenomenon looks similar, the principle is not the same.”Fluid is actually a very important part of modern life.By doing such a surface tension experiment, we can give you the opportunity to pay more attention to and discuss the fluid, and to understand more about the fluid.The Neville Stokes equation, which explains fluids, is still one of the world’s six biggest unsolved mathematical problems.”Chen Zheng said.”Microgravity fluid physics is actually a new discipline of fluid physics.”According to Kang Qi, a researcher with the Institute of Mechanics of the Chinese Academy of Sciences, liquid bridge experiments on the space station are the scope of microgravity fluid research. The core module of the Chinese Space Station is equipped with more than a dozen experimental cabinets, two of which focus exclusively on microgravity fluid science.Space parabolic experiment this tiangong classroom, the Top flow of the Beijing Olympic Games “ice pier pier” also high-profile appearance.When it was thrown from the space station, it did not curve like it did on the ground, but flew horizontally.That makes sense, considering that in the space station’s microgravity environment, objects are almost immune to gravity.But why would you do such a simple experiment on a space station?”Flat throw movement is very common in our life. It seems simple, but it contains a lot of science.”Zhang Jian, a physics teacher at the second high school affiliated to Beijing Normal University, said.Zhang Jian introduced that the flat throwing movement refers to the movement of the object under the action of gravity after it is thrown out at a horizontal initial speed without air resistance.Consider this thought experiment: if we do a flat throw on a high mountain, an object will fall to the ground;If you throw an object at a higher speed, it will fall farther.So, if the velocity of the ejection is high enough, is it possible that it could become a satellite orbiting the Earth without falling back to earth?”The idea was first suggested by Isaac Newton, so we call it Newton’s Mountain Gun experiment.”Zhang said the “sufficiently large” speed could be calculated using his knowledge of middle school physics: about 8,000 meters per second.”This speed is called the first cosmic speed, which is the minimum launch speed for a satellite and the highest orbit speed of any satellite in orbit.Our space station is running close to the first cosmic speed.”Zhang jian said.Source: Science and Technology Daily, Beijing, March 23, read: Sun Shijian