Social media controversy over a glass of water that doesn't float on the Chinese space station: what science says

Recently, a video recorded on the Chinese space station Tiangong caused a stir on social media. It shows a glass of water sitting still on a table, which many people found suspicious and began to claim the video was fake, as water should float since there's no gravity in space .

Despite these beliefs, the video is real , as it was recorded three years ago during a class for schoolchildren in which astronauts were demonstrating how water behaves in space. According to space researcher Jordan Bimm, who spoke to AP News , what happens is that, even though there is no gravity, water doesn't just fly away .

Why doesn't the water come out of the glass?

Water molecules tend to stick together thanks to a property called surface tension , and they also "stick" to the glass of the cup, so the water can easily stay inside. It's also worth noting that the cup was attached to the table with Velcro , a common practice on space stations to prevent objects from floating away and getting lost.

Astronauts do other very interesting experiments

Throughout the video, they conduct various experiments, such as placing a ping-pong ball in water to demonstrate that it doesn't float, because without gravity, there are no buoyant forces. In another, they create a film of water that acts like a magnifying glass . And in one of the most striking experiments, they form a sphere of water with a bubble inside , which reflects the astronaut's image like a mirror.

All of this serves to illustrate how the properties of water change when gravity is removed , but the problem is that many of those who criticized the video didn't see these experiments and only focused on the image of the glass that wasn't moving. Hence the erroneous conclusions.

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