On the afternoon of March 23, 2022, China Space Station "Tiangong Classroom" started. Teacher Wang Yaping used a table tennis ball and a glass of water as props to vividly explain the principle of buoyancy and how buoyancy "disappears" in space. . The Tiangong Classroom is fascinating and has benefited a lot from us who are eating melons on the ground. The video was made into an English version and circulated on the Internet. It also attracted the attention of many foreign viewers. Many people praised "this is excellent" and can "better understand." science".
Tiangong Classroom is popular all over the world
However, what is unexpected is that three months later, this video suddenly became "popular" again, because some foreign netizens discovered a "shattering secret" - it was probably shot on the ground Yes, this means that the Chinese astronauts did not go to heaven at all, and the space station is also fake!
What on earth is going on?
If you look carefully at the above picture of space classroom teaching, it is not difficult to find that the three Chinese astronauts are standing steadily in the space station, and the "eagle-eyed foreign netizens" even noticed that the water in the cup on the table is also flat. , exactly the same as on the ground. So he tweeted: "Faking Space is a Television Show" followed by the expressions of clowns and devils:
"Foreign netizens" questioned the staged photo over a glass of water
Foreign netizens' This "important discovery" quickly aroused enthusiastic responses from some domestic accounts, and they all began to use their imaginations to ridicule "landing at the Hengdian Space Center" and "should be changed to goose-stepping."
Although these ignorant comments seem ridiculous, doubts about science must be answered with science after all, so today we will seriously talk about why the water in the cup is flat and does not float in space; Tiangong Is the classroom really a "Hengdian work"?
If you have watched Teacher Wang Yaping’s space lectures , you should be deeply impressed by her action of picking up the cup from the class surface. Wang Yaping held the cup with both hands, carefully lifted it up, exerted force, and finally "pulled" the cup off the table.
Wang Yaping "drags" the cup away from the table
Why is it so laborious to pick up a water cup in space? Because there is Velcro on the bottom of the cup, and the strips on the table are also Velcro straps, the cup used in the experiment can be fixed on the table with Velcro, otherwise it will float away.
In fact, there are similar Velcro straps in many places in Chinese and foreign space stations. They are also found on pens, forks and spoons used by astronauts, bags for food and drinking water, and tools and items. As long as they are attached, they will not Flying everywhere.
Velcro is widely used in the space station
Some friends said, why not use magnets or magnetic patches? Wouldn’t that be more convenient? This may be because the space station is mainly used for various space science experiments and needs to maintain a relatively "clean" electromagnetic environment. Using too many magnets may cause interference to some sensitive measuring instruments and equipment. There is no interference problem with Velcro. It has glue on the back. You can stick it wherever you need it and just tear it off when not in use.
Similarly, in order to maintain body posture in the space station, astronauts will always insert their feet into the buckles on the inner wall of the cabin to stabilize themselves, otherwise they will float around and be unable to work.
Now let us talk about the "buoyancy loss" experiment in space.
When the table tennis ball is pushed down, the horizontal plane is disturbed and tilts.
It is said that there is weightlessness in space. Why does the water stay "honestly" in the cup and the water surface remains as horizontal as on the earth?
Many people think that in the weightless state of space, water will naturally form into a spherical shape. It should not stay in the cup, but will float in the air, just like what the Russian astronaut once demonstrated:
Russian astronaut demonstrated Swallowing water balls in space
When water does not come into contact with other objects in the space station, it will indeed automatically form a round ball.This is because the space station is flying around the earth, and it and all the objects inside it are in a " microgravity " state, which is physically similar to an "inertial reference frame". In the inertial reference frame, since there is no gravity or other acceleration changes, the force of hydrogen bond between water molecules plays a dominant role, which is macroscopically represented as " surface tension ". This surface tension will pull the water into a spherical shape. .
Surface tension comes from the force of hydrogen bonds between water molecules
Because of surface tension, will water only form a spherical shape under microgravity? Not so.
After we wash our hands, it is difficult to get rid of all the water just by shaking our hands. The hands will be wet because the water will stick to the skin. If you carefully observe Wang Yaping's space course, you will also find that when she puts the table tennis ball on the water surface of the cup, the ball will obviously "sink".
The table tennis ball "sinked" obviously after contacting the water
Through the screenshot of this video, we can easily see that even if Wang Yaping did not "press" the table tennis ball, the part of the ball submerged in the water was more than one-third of its diameter. one. The reason for this phenomenon is the "infiltration effect" of water. Similarly, even under the microgravity conditions of space, water will be restrained in the cup due to the infiltration phenomenon and cannot float out.
Water infiltration phenomenon
Water molecules are polar molecules, because the only electron of the hydrogen atom in the molecule is occupied by oxygen, causing an imbalance in the charge distribution on the surface of the molecule. The hydrogen atom end has a weak positive charge, while the oxygen atom Because it "robbed" two electrons, it becomes negatively charged. In this way, hydrogen bonds are formed between water molecules because of the attraction between positive and negative charges. But the molecules on the surface of the glass or table tennis ball have a stronger attraction to the water molecules, so the water molecules are pulled to the surface of the glass or table tennis ball. This is the wetting phenomenon.
Due to the existence of wetting phenomenon and the surface tension between water molecules, as long as you carefully pour water into the cup, it will form a "horizontal surface" like the ground and will not escape easily. This is why it’s impossible to drink water from an ordinary cup in space.
This "horizontal plane" is not caused by the earth's gravity, but the result of the interaction between infiltration and water surface tension.
The water will not spill out when the cup is rolled
Because the space station is a microgravity environment, infiltration and surface tension play a leading role. Even if we turn the cup over in the air, the water will not spill out of the cup. This is the magic of science. .
As for the questioning and ridicule of a few "foreigners" or some "smart people" in China, it may be because they have little knowledge of science, or it may be a deep-seated stereotype . As long as they don't feel embarrassed, it's okay. There it goes.
#The official response to the external website questioning that China’s space station is fake#
#China Aerospace official responded to the external website’s questioning and said to read more#
