China's Shenzhou-23 crew gave students from Hong Kong and Macao a science lesson from the Tiangong space station on Wednesday morning, with Lai Ka-ying, the first astronaut from Hong Kong, demonstrating the phenomenon of wringing a wet towel in space.
Hundreds of students from the Hong Kong Special Administrative Region (HKSAR) and the Macao Special Administrative Region (Macao SAR) gathered at Tsuen Wan Public Ho Chuen Yiu Memorial College in the HKSAR for the special "Tiangong Class."
The event featured interactive communication between the astronauts and students on the ground.
"Look, the water doesn't drip down. It clings to the surface of the towel. Let me squeeze harder. Now it looks like a glove. This is because in a microgravity environment, water's surface tension plays a dominant role. Water molecules hold tightly together and adhere to the surface," Lai said.
She then explained the proper way to handle a wet towel aboard the space station.
"Actually, we don't wring wet towels like this up here, because it's easy to accidentally shake off small water droplets, and collecting them would be quite troublesome. Can you guess how we deal with a wet towel in space? The correct way is to let it air-dry naturally, or seal it and dispose of it," she said.
Commander Zhu Yangzhu and astronaut Zhang Zhiyuan also took part in the event.
The three astronauts were launched aboard the Shenzhou-23 spacecraft on May 24.
Chinese astronaut demonstrates towel-wringing in Tiangong space class
Chinese astronaut demonstrates towel-wringing in Tiangong space class
