1, Space Turn Experiment In the Tiangong Classroom, astronaut Ye Guangfu performed "Space Turn". The first attempt to turn around normally failed-every time he twisted his upper body, his lower body would involuntarily twist in the other direction. Why?
The reason why we can move forward and turn around easily on the earth is because there is friction on the ground. Without the help of friction, it is naturally difficult for astronauts "floating" in the air under weightlessness to turn their bodies. Because the angular momentum of astronauts is conserved, the upper body turns left and the lower body turns right.
In the second attempt, the astronaut achieved body rotation by rotating his arm. This can also be explained by the conservation of angular momentum. ?
2. In the disappearing buoyancy experimental space station, astronaut Wang Yaping put a ping-pong ball into the water and found that it could not float.
This is because the essence of buoyancy is the pressure difference between the upper and lower surfaces of an object, and the premise of buoyancy is the existence of gravity. In weightlessness, buoyancy will fail, so table tennis in space can sink into the water, which is impossible on earth.
3. Water film tension experiment The water on the earth will flow from high to low due to gravity. However, in the weightless environment, astronauts transferred water to a special iron ring, and because of the surface tension of water, a crystal clear water film was formed, which would not break.