At 15:40 on December 9, 2021, the first lesson of "Tiangong Class" was officially taught. It was the first time for Chinese astronauts to teach in space after eight years. "Space teachers" Zhai Zhigang, Wang Yaping and Ye Guangfu gave a wonderful lesson on space science to young people in China's space Station. This was the first space teaching activity in China's space station. The three astronauts demonstrated six space science experiments, including space cell, space turn, loss of buoyancy, water film tension, water balloon optics, and water effervescent tablets
Experimental phenomenon: A lot of bubbles will be generated when the effervescent tablet meets water. Then what happens when the effervescent tablet meets the water balloon in space? Wang Yaping injected the blue pigment liquid into the water balloon and turned it into a blue water balloon. The effervescent tablet was inserted into the blue water balloon. Most of the bubbles generated by the effervescent tablet were wrapped in the water balloon and turned into a bubble ball, like a blue earth. As the bubbles increase, the water balloon gradually becomes a "bubble ball" filled with aromas.
Principle interpretation: The effervescent tablet usually contains sodium bicarbonate and citric acid (or other weak acid). When it is thrown into the water cup on the ground, the acid and water react to produce carbon dioxide bubbles. Due to the existence of buoyancy, the carbon dioxide bubbles rise quickly and then disappear on the surface of the water. Inside the space station, the bubbles spread evenly, unaffected by buoyancy, with most remaining in the balloon and a few breaking through the surface and spreading into the air.
