Recently, some foreign netizens claimed that the water cup used by Chinese astronauts in the "Tiangong Classroom " teaching experiment and the water contained in it did not float in a weightless environment, questioning that the location where the video was shot was not in space. On June 30, China Aerospace Science and Technology Corporation, China Aerospace New Media Matrix "Our Space" and China Association for Science and Technology Science and Technology Communication Center collectively mobilized to answer questions on Zhihu official account: The water cup is for convenience During the experiment, it was fixed on the table; if the water in the cup did not spill out, it was because the surface tension of the water was at work. These knowledge points have been explained in previous Tiangong classes. "Our Space" lamented: "Read more, watch more previous videos, and have the ability to think independently..."
I believe that after reading the official explanation, you may still not understand: What role does the surface tension of water play? ? Why do foreigners think that China Space Station is fake?
The reason is very simple, because the glass of water does not look like it should in a vacuum environment and in a weightless state. Under normal circumstances, liquids float in space and take on an almost perfect spherical shape, which is one of the most standard shapes for liquids in space.
Why doesn’t the liquid in the water cup in our heavenly palace float in space?
The cup is fixed on the table and adheres to the wall of the cup by surface tension (that is, the water does not leave the cup, and there is an adhesion between the cup wall and the water). The reason for this phenomenon is also very simple. There is infiltration of water and other objects. and non-infiltration conditions. To put it in a better way, will the water stick to it?
When water comes into contact with the surface of an object, non-wetting means non-adhesion. The attraction between water molecules is greater than the attraction between water molecules and the surface of the object. This in turn causes the water contact surface to tend to shrink, and the liquid becomes round and can even move freely. Aren’t the water drops on the lotus leaf able to roll around freely?
Wetting means that water can adhere to a solid, and glass is a material that water can wet. When water is placed in a glass, water molecules adhere to the walls of the bottle. That is, the attraction between water molecules and the wall of the glass bottle is greater than the attraction between water molecules. In this way, the attraction of water molecules cannot pull themselves into a spherical shape. Is this explanation of
acceptable to everyone? Do you think it is correct? Discussions are welcome.
