王亚平太空授课，演示水膜变水球
China's second female astronaut, Wang Yaping, has delivered the country's first-ever video lecture from space.
Speaking to students via live video, Ms Wang used spinning tops, a ball, water and a fellow astronaut to explain physics in zero-gravity.
She was speaking from the Tiangong -1 space laboratory, where the Shenzhou spacecraft is currently docked,
China's fifth manned space mission, Shenzhou -10, is scheduled to end around 25 or 26 June. The crew is also expected to attempt a manual docking later on Thursday.
This will involve getting back inside their Shenzhou capsule, unhooking from Tiangong and then flying around the lab to re-attach the capsule to the laboratory.
Ms Yang used difference experiments to demonstrate the concepts of weight and mass in space.
After showing how normal scales did not work in space, she used a special scale to measure the mass of crew commander Nie Haisheng, using Newton's second law of motion - measuring the mass of an object through force and acceleration.
At another point, to show how objects move in the microgravity environment of space, she asked her colleague to help her rotate 90 degrees, and then 180 degrees, from the floor of the laboratory.
Spinning tops were used to create gyroscopic motion in space, and a ball attached to a string to demonstrate pendulum motion.
Towards the end of the class, Ms Yang made a film of water using a metal ring, explained by the increased surface tension of water in space. She then turned the film of water into a water ball by pouring more water onto it, to wide applause from students watching in China.
Around 330 primary and secondary school students watched the lecture from a special classroom in Beijing, where they could also ask Ms Wang questions through a live video feed, state media said.
In response to a student's question, Ms Yang described what she could see in space.
" The stars we see are much brighter, but they do not twinkle," she said, explaining this was due to the lack of Earth's obstructing atmosphere.
" The sky we see isn't blue, but black. And every day, we can see the sun rise 16 times because we circle the Earth every 90 minutes."
An estimated 60 million students and teachers around China were also expected to watch the lecture live, the Ministry of Education said.
【新闻快讯】 6月 20日上午 10时许，神舟十号航天员进行中国首次太空授课，女航天员王亚平担任主讲，成为中国首位“太空教师”。神舟十号航天员在天宫一号展示了失重环境下的物理现象。
在大约 40分钟的授课中，航天员通过质量测量、单摆运动、陀螺运动、水膜和水球等 5个基础物理实验，展示了失重环境下物体运动特性、液体表面张力特性等物理现象。他们讲解了实验背后的物理原理，并通过视频通话与地面课堂师生进行互动交流。
地面课堂设在位于北京市海淀区的中国人民大学附属中学。包括少数民族学生、进城务工人员随迁子女及港澳台地区学生代表在内的 330余名中小学生参加了地面课堂活动，全国 8万余所中学 6000余万名师生通过电视直播同步收看。
