Wang Yaping, the second Chinese woman in space, demonstrated how a variety of objects — from a spinning toy to a bubble of water — behave in space. Xinhua

Commander Nie Haisheng made a show of crossing his legs in the air in a meditation posture — which only a martial arts master can do in the movies, but is impossible for people on Earth.

Wang smiled as she pushed Nie into the wall of the module with a gentle nudge of her hand, and went on to gulp down a floating drop of water.

"Thanks to the weightless condition, we're all masters," she joked.

The two then conducted a string of experiments that demonstrated how objects behave in low gravity — from a bubble of water to a spinning toy.

Wang started with a question of how astronauts measure weight in the weightless orbiter.

Nie demonstrated by measuring his weight on the special scale onboard the orbiter, which was designed on the basis of Newton's second law of motion, or measuring the mass of an object through net force and acceleration.

It was followed by an experiment where she held out a small ball tied to a string. "What will happen if I let the ball go?" she asked.

The ball did not swing as it would on Earth but stayed suspended. When she pushed the ball gently, the ball moved in a circular motion, which stirred the classroom a bit.

Wang later pushed a static gyro and a moving gyro to change the way they move.

What appeared to excite students most were the experiments with water.

Wang made a film of water with a metal ring, and then a ball of water to explain how zero gravity magnified surface tension.