Top News·Henan Business Daily Chief Reporter Han Zhonglin Reporter Yang Xiaoyan Intern Zhang Jiaqi
On October 12, three astronauts including Chen Dong , Liu Yang , Cai Xuzhe and other three astronauts will bring you the third section of Tiangong Classroom . Interesting and exciting content is worth looking forward to.
The first space teaching in 2013 has been around for nearly 10 years. China's aerospace technology has made continuous breakthroughs. On this basis, Chinese astronaut has served as a "space teacher" many times, bringing scientific space teaching to the people of the whole country, and forming a unique space science popularization education brand "Tiangong Classroom".
Space teaching has given countless children the wings of dreams, helping mankind to accumulate strength on the road to conquering the stars and seas.
2013 space teaching. Data picture
The first space teaching has been taught nearly 10 years
"Hello everyone, I am Wang Yaping . This lecture is taught by me..." On June 20, 2013, a kind voice came from the Tiangong No. 1 experimental cabin, more than 300 kilometers from the ground.
Astronaut Wang Yaping gave a space lecture for the first time with the assistance of Nie Haisheng and Zhang Xiaoguang. This lesson lasted about 50 minutes.
This space teaching is mainly for primary and secondary school students. The "space teacher" demonstrated experiments such as mass measurement, single pendulum movement, gyroscope movement, water membrane and water balloon production, allowing children to understand the characteristics of object movement under weightless conditions, the role of liquid surface tension , and deepen their understanding of basic physical concepts such as mass, weight, and Newton's law.
mass measurement
gravity is caused by the attraction of the earth. How to weigh mass in weightless space? What is the principle of the use of weighing equipment in space? Space teacher Wang Yaping told us that the constant force generated by the "spring-cam" mechanism and the grating speed measurement system measure the acceleration of body movement, and according to Newton's second law (f=ma) the body's mass is calculated.
Single pendulum motion
On the ground, the thin rope on the bracket is tied to a small ball to form a single pendulum system. Pull up the ball and let go, and the ball begins to swing back and forth, and the movement cycle is related to the length of the rope and the acceleration of gravity. Finally, the ball stopped swinging under the action of air resistance.
But there is no gravity in space and does not cause swing; if the ball is given a small initial velocity, the ball can move around the bracket axis, but a sufficiently large initial velocity is required on the ground to achieve it.
Gyro movement
High-speed rotating gyro's rotation axis will remain unchanged in the inertial space. In space, touch the high-speed rotating gyro and the stationary gyro with your hands. Although the high-speed rotating gyro will cause slight shaking, the axial direction of its rotation axis remains unchanged, while the stationary gyro will roll. Because the high-speed rotating gyroscope has good directionality, the spacecraft can use gyroscope for spatial orientation.
The force that makes water film and water balloon
The force that acts on the liquid surface and reduces the surface area of the liquid is called liquid surface tension. The water film formed after the metal ring is inserted into the water bag will not break. If a "Chinese knot" is pasted on the surface of the water film, the water film will still be intact. This is the result of the highlighting of the surface tension characteristics of liquids in a weightless environment in space.
Inject water into the water film, and the water film quickly turns into a large crystal clear water ball. Such a perfect spherical shape can only exist in a microgravity environment, because the surface tension of the liquid on the ground is difficult to resist the influence of the earth's gravity, and the water ball will inevitably deform.
Nearly 10 years have passed since this space teaching. Back then, more than 60 million primary and secondary school students watched the live teaching broadcast across the country. Now they have grown up, and the seeds of the space dream have also thrived in their hearts.
"Many children like aerospace because of this, and some children apply for the aerospace major because of this. Some children have even become my colleagues now, which is also something that makes me very proud and proud." Wang Yaping once said in an interview.
2021 space teaching. Data picture
China's first space science popularization education brand "Tiangong Classroom", launched
With the long-term operation of China's space station , in 2021, China's first space science popularization education brand "Tiangong Classroom", was launched in a series, with Chinese astronauts serving as "space teachers", and they were carried out through collaborative interaction between heaven and earth.
At 15:40 on December 9, 2021, the first lesson of "Tiangong Classroom" started, and was taught on the China Space Station by "Space Teacher" on Shenzhou 13 .
This lecture set up a ground main classroom in the China Science and Technology Museum, and a ground sub-classroom in Nanning, Guangxi, Wenchuan, Sichuan, Hong Kong and Macau.
The first "Tiangong Classroom" project includes eight items such as the display of astronauts' in-orbit working and life scenes, space cytology research experiments, space turn, buoyancy disappearance experiments, water membrane tension experiments, water balloon optical experiments, effervescent tablet experiments, and interactive communication in the world.
Space Cytology Research Experiment
When the cells are placed in the case of gravity or the is completely weightless, the growth morphology of the cells will be different.
Live cardiomyocytes will produce bioelectricity during their life activities. Bioelectricity will stimulate the fluorescent substances in fluorescence microscope , and fluorescence can be observed through the display screen. Cardiac myocytes have the characteristics of automatic rhythmic contraction, so they can be observed rhythmically under a microscope.
In space, its function and gene characterization will change. After returning to the ground, the gene characterization will basically return to the ground state, but the characterization of some genes will still change.
Space Turning
Turn, this ordinary action with zero difficulty coefficient on the ground, to be implemented in space, one side of the arm needs to be drawn in circles. When the body rotates, the rotation speed of the arm retracts will become faster. In the environment of
microgravity , astronauts do not contact space station , similar to the ideal state to verify that "there is no external torque, the object will be in the conservation of angular momentum." When the astronaut turns the upper body to the left, according to the principle of angular momentum , the lower body will turn to the right.
When an astronaut stretches his body, because the mass distribution is far away from the rotation axis and the rotational inertia is relatively large, the angular velocity slows down. In layman's terms, it turns slowly. When the limbs are retracted, the rotational inertia is small and the angular velocity will increase. The intuitive feeling is that the rotational speed becomes faster.
buoyancy disappearance experiment
On the ground, if the ping-pong ball is put into the water, it will float to the water surface. So do the same experiment in space. Table tennis ball "float or not"? The answer is: not floating!
This experiment shows the phenomenon of buoyancy and gravity. Buoyancy comes from the pressure difference of the liquid at different depths caused by gravity. When the gravity disappears, the internal pressure of liquid is the same, and the buoyancy disappears. However, it is difficult for the earth's surface to disappear, and this experiment is difficult to visually display. Under the microgravity conditions of the space station, the associated relationship between buoyancy and gravity can be clearly manifested.
water film tension experiment
Wang Yaping put the origami flowers made by her and her daughter on the earth into the water film, and the beautiful flowers bloomed instantly.On the ground, the surface tension of the liquid in the water droplets is affected by the earth's gravity, and the experimental effect is not obvious; in a space weightless environment, there is only one liquid surface tension on the section of the water molecules on the surface of the water film, and the water droplets are spherical. When the flower is close to the surface of the water film, the flower gradually expands under the action of the surface tension of the water film and .
Water balloon optical experiment
Inject water into the water film, and a water balloon was obtained. Then, a bubble was injected into the water balloon. Through the water balloon and the bubble, you can see two images of one positive and one negative.
On the ground, the water droplets are affected by the gravity of the earth, and they are small on the top and large on the bottom. In space, due to the microgravity environment, water droplets appear transparent balls under the action of surface tension. The spherical water droplets are equivalent to two convex lenses combined together. The light refracts twice through it, thus forming an inverted portrait; when a bubble is injected into the water balloon, the light refracts four times through it, thus forming a standing portrait, where the inverted image is the result of the light refracting twice in the water balloon, and the upright image is the result of the light being shot into the bubble four times. These are all optical phenomena caused by the refraction principle of light.
effervescent tablet experiment
In the ground environment, throw the effervescent tablets into the water ball, and you can see the bubbles floating up. However, in the weightless environment of the Chinese space station, due to the disappearance of buoyancy, the bubbles generated by the effervescent tablets thrown into the water no longer float up, but squeeze each other. The water ball will also be supported by bubbles, and you can see the effect of the water ball expanding little by little.
2022 Space Class . Data picture
In March this year, the second lesson of "Tiangong Classroom" came as scheduled
On March 23, 2022, the second lesson of "Tiangong Classroom" came as scheduled. The "space teacher" is still taught at the China Space Station by the astronauts of the Shenzhou 13 crew, Zhai Zhigang, Wang Yaping and Ye Guangfu.
This space teaching will set up a ground main classroom in the China Science and Technology Museum, and two ground sub-classrooms in Lhasa, Tibet and Urumqi, Xinjiang.
During the teaching for about 45 minutes, the "space teacher" demonstrated the space "ice and snow" experiment, liquid bridge demonstration, water and oil separation, and space throwing experiments.
Space "Ice and Snow" Experiment
Gently squeeze the water bag containing supersaturated sodium acetate solution , and a liquid ball with blisters slowly "run" out of the tube mouth and hovered in the space station cabin. Then, after touching the liquid ball with a small stick stained with powder, the liquid ball with blisters began to "freeze".
On the ground, crystallization using saturated liquid is a method of isolating and purifying solid substances. The small sticks stained with powder act as the role of condensed nucleus , and the small crystals also begin to condense quickly and crystallize with water molecules to form crystals of hydrated sodium acetate, and at the same time release a large amount of heat.
Liquid Bridge Demonstration
Liquid Bridge is a piece of liquid connected between two solid surfaces. In the liquid bridge demonstration experiment, Wang Yaping held two transparent plastic boards in his hand, and Ye Guangfu squeezed water on the surface of plastic board . The two plastic boards gradually approached, and the water connected a "bridge" between the boards. What’s amazing is that Wang Yaping then gently pulled the plastic board with both hands, and the “bridge” was still not broken. The surface tension of the liquid is very weak. On the ground, gravity will pull the liquid downward, making it difficult to achieve the liquid bridge phenomenon.
Water and oil separation
On the ground, water and oil are naturally layered after mixing, and the oil is on the upper and lower water. So in the space station, will water and oil be naturally layered? The answer is: No.
Under the same volume, the density of water is greater than that of oil and the mass of water is greater. According to the centripetal force formula F=mrw2, when the angular velocity w and radius r are the same, the mass m is large, and the greater the centripetal force required by the water droplet, that is, the greater the equivalent centrifugal force , so the larger the water is thrown to the bottom of the bottle.Water and oil are stratified.
space throw
In the space throw experiment, the top stream "Bingdundun" appeared. Wang Yaping and Ye Guangfu threw "Bingdundun" in turn. It did not fall along the trajectory of parabola , but moved forward at a constant speed in the original direction. This is because in the space station cabin, objects are almost not affected by gravity. No matter which direction they are thrown, they can almost be regarded as a linear motion at a constant speed, because objects are only affected by weak air resistance, and the changes in velocity direction and size are very small.
Space teaching gives children the wings of dreams
Stars and seas never stop, ask the sky and the fire is passed down. Behind this step by step "the road to heaven" is the wisdom and hard work of generations of astronauts. "Tiangong Classroom" tells children not only the knowledge points of scientific experiments, but also the exploration of the unknown aerospace spirit.
Wang Yaping once said in an interview that space teaching has created a new model and new method for popular science education and primary and secondary education in our country. It can be said that so far it is the world's most widely-received, largest and longest teaching live broadcast activity.
Three space teachings have inspired countless children's enthusiasm for science, interest in research and exploration, and courage to pursue their dreams. Children believe that astronaut Wang Yaping said, "Dreams are like stars in the vast universe, which seem out of reach, but as long as you work hard and persist, you will definitely be touched." The
space station is also an important space science popularization education base. It contains unique and rich educational resources and has special advantages in inspiring the public, especially young people, to promote the scientific spirit and love the aerospace industry.
Shenzhou 14th flight crew will continue to carry out the "Tiangong Classroom" on October 12. According to China Manned Space Engineering Office , astronauts interact with the ground and carry out some popular science activities during flights on the space station, which will become normal in the future.
