Why don't the water in the space station not float from the cup?

Generally speaking, in the heavy environment of space, water should float in the air to present spherical shape, just like the figure below.

However, during the teaching of Shenzhou 13 space, a photo of a water cup made everyone a little doubtful. It can be seen from the picture that the water in the water cup seemed to be "locked" firmly and did not float. What is the scientific principles behind this? Xiaobian will open the doubts in my heart today.

Water does not float from the cup, it is the tension work

Water cannot float out of the water cup. Behind this phenomenon is actually the surface tension of the water. Even if the cup is inverted, the water will not flow down. This is the characteristic of water in the heavy environment of space. In fact, on the ground, the liquid also has surface tension, but it is affected by factors such as gravity and is not easy to be observed.

As we all know, when the cup is full, the water will flow down the wall of the cup, but if you observe it carefully, you can find that when the cup will be full, the horizontal plane will gradually rise. When the cup is higher, the water will not fall. The surface of the water is like a bulging balloon. As the water increases, it is slowly plump, and it is not until a certain degree of high cups that the water will flow off the cup wall. When the water will not fall, the water surface is tightly covered with a layer of water film to prevent the water from flowing down. This is the surface tension of the liquid.

How do astronauts drink water in space?

In the environment of space loss, since the water does not flow to the low point, how can the astronauts "pour" the water into the cup? Aerospace experts introduced that there are many ways to put water into the cup. For example, first seal the cup with a film, then use a needle tube to push the water. After the water is attached to the cup, remove the membrane. If you drink water in a cup in space, the astronauts can fly out with their mouths, so the water will fly out immediately.

As for why the water cup can be placed on the table smoothly as it is on the ground? This is actually easy to achieve, as long as you stick to the bottom of the cup and the desktop.

China Space Station Space Lecture is a new way of opening a new popular science education. Netizens can observe these details, which shows the importance of global space science popularization. In space lectures, almost every detail reflects the differences between heaven and earth, breaking people's daily life experience and original cognition. It allows the public to think about the common phenomenon of the public about the common phenomenon of life, and to convey the attitude and spirit of respecting science in virtue.

Source: Chinese Aerospace

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