Eight years ago in the cloud space classroom, were you there? What are you doing now after listening to the class?
As a national space laboratory and an important space science education base, the Chinese space station contains unique and rich educational resources. On June 20, 2013, Shenzhou 10 astronaut Wang Yaping, the first space teacher in China, with the assistance of Shenzhou 10 astronauts Nie Haisheng and Zhang Xiaoguang, opened a space-earth interactive space class for more than 60 million primary and secondary school students across the country, and carried out five basic physics experiments: mass measurement, pendulum motion, gyro experiment, water film experiment and water polo experiment.
Eight years ago, a class of nearly fifty minutes made countless teenagers feel the charm of science and technology. The power of role models is infinite, and Wang Nan, a sophomore who watched the live broadcast at the time, was deeply attracted by the combination of space environment and physical experiments, and this year she successfully fulfilled her dream and joined the aerospace industry.
December 9, 2021 at around 3:40 p.m
Version 2.0 of our Space Lessons is officially launched
Still led by Teacher Wang Yaping,
Shenzhou Thirteen commanded Zhai Zhigang
and astronaut Ye Guangfu
"Feel Good" multiplier participates in the lesson
Image source: CCTV News
The "Feel Good" team demonstrated eight space-taught projects for audiences around the world, including cytology experiments in weightless environments, object motion, and liquid surface tension. Didn't see the live stream? It doesn't matter, Hangzhi sorted out this hour-long course for everyone, from knowledge points to videos are sorted out for everyone, quickly collect this free space course, and astronauts feel the charm of space and science together!
1. Astronauts in orbit work and life scene display
At the beginning of the course, Mr. Apin "floated" and took us to visit the interior of the space station, including the work area, living area, science experiment area, fitness training area, etc.
2. Experimental demonstration of space cytology research
Then, Teacher Ye Guangfu showed us the miraculous changes of cells in space. We can see relevant studies of cell growth and development under weightless conditions. The following figure can also see the cells beating.
3. Space turns
In this experimental part, Mr. Apin and the children do an interaction. Let the children try to stand up and turn back and then turn back, the children are extremely easy to complete. But it is this extremely difficult action on the ground, but it is extremely difficult in space, and the action is extremely distorted.
Through The demonstration of teacher Ye Guangfu, we can know that when we turn around in space, the upper body and the lower body will show the opposite direction. In fact, there is a physical knowledge in the middle, called angular momentum.
Chen Zheng, deputy head of the Science Popularization Lecturer Group of the China Science and Technology Museum, said in an interview with the Global Times that angular momentum is a physical quantity that describes the rotation of an object. What this test shows is that in a microgravity environment, the astronauts in the case of not touching the space station, similar to the ideal state to verify that "there is no external moment, the object will be in the conservation of angular momentum." Therefore, when the astronaut's upper body is rotated to the left, according to the principle of angular momentum balance, the lower body will turn to the right.
Another action is when the astronaut stretches his body, because the mass distribution is farther away from the axis of rotation, the rotation inertia is relatively large, so the angular velocity is slowed down, and the speed of the turn will slow down. When the limbs are withdrawn, the rotational inertia is small, and the angular velocity increases, so that the rotational speed becomes faster. Teacher Wang Yaping also jokingly said that this action is very similar to the movement of a figure skating competition.
Buoyancy disappearance experiment
This experiment is both simple and intuitive, and we all know that the reason why the ship can run on the water is because of buoyancy. In this section, Teacher Wang Yaping asked the students to press the ping-pong ball under the water with chopsticks on the ground, and then when they released their hands, the ping-pong ball would quickly float back to the water. But through the experiment of teacher Ye Guangfu, we can see that when the ping-pong ball is pressed into the water in the space station, the ping-pong ball will not float back to the surface.
What is the reason for this?
In fact, the physical knowledge behind this is called "buoyancy and gravity.". Buoyancy arises from the difference in pressure of the liquid at different depths caused by gravity. When gravity disappears, the internal pressure of the liquid is the same, and the buoyancy is also gone. Therefore, under the condition of weightless space station, buoyancy will disappear, and the ping-pong ball will naturally not float up. Water film tension experiments & water balloon optics experiments
In both experiments, we are talking about physical phenomena related to "water."
Wang Yaping conducted a water film experiment
First, in the weightless environment of space, the water droplets shrink under the influence of surface tension into a water ball that is close to a perfect sphere, rather than the water droplets we see on Earth.
Second, we just mentioned that buoyancy in space is almost zero. Chen Zheng said that when the astronauts punch a bubble into the water balloon, the reason why the bubble will not float upwards is precisely because there is no buoyancy. We can see that the water balloon is transformed into two parts by the bubble, and the bubble is surrounded by water. The astronaut's face is presented separately upright and upside down.
In fact, the reason for this is because the two parts of the water balloon at this time become two lenses, and the outer ring is a convex lens, so it presents an inverted image, and the inner ring is equivalent to a combination of two concave lenses, and at this time there is another upright image. Therefore, you can see two images of one positive and one upside down at the same time in the water balloon.
Effervescent tablet experiment
We know that throwing an effervescent tablet into the water on Earth will produce countless small bubbles that will float up to the surface of the water and then disappear into the air. However, throwing an effervescent piece into the water in space has very different results.
This phenomenon stems from the biggest difference between space and Earth: space is a microgravity environment. We just mentioned that space is a place with almost no buoyancy, so throwing an effervescent piece into the water on the space station, the bubbles it produces will not float, but squeeze each other, and the water balloons will be held up by the bubbles, which is extremely beautiful.
Interactive communication between heaven and earth
In the final question-and-answer session, students from Nanning, Guangxi, Wenchuan, Hong Kong, Macao, and Beijing all raised their own questions to the astronauts: such as whether astronauts can walk normally like on the ground in the space station, whether astronauts will float up when they sleep, whether they will dream, how to solve the water of the space station, and other interesting questions, and the astronaut teachers have also answered one by one. Since there are many questions, interested readers can click into the video to see the answers.
"The flying dream never loses weight, and the tension of the scientific dream is infinite!"
Compared with 8 years ago, our technology, heaven and earth communication equipment, etc. have been greatly improved. For young people, science and technology science is still the top priority. The seeds of China's aerospace dream are being sown among the stars, and it is also expected that more and more teenagers will join the construction of China's aerospace industry. If the youth is strong, then the country is strong!