In a video call beamed from outer space by Shenzhou XII taikonauts at Tiangong space station on Friday, Hong Kong students got the chance to ask their burning questions about the lives of the three Chinese astronauts. The video call also featured a Q&A session in which experts, including the first Chinese national to enter space Yang Liwei, fielded questions from the excited pupils.

1: A student from Scientia Secondary School:

Can you exercise in the space station? Would you show us?

Nie Haisheng: Sure. We must exercise to reduce the effects of a weightless environment. The station has a lot of exercise equipment, such as a space bicycle and treadmill. When running on the machine, we need to fix our upper body on it to keep balanced. Riding the bicycle will help us build muscle strength and improve cardiopulmonary function.

In space, we can not only ride bicycle using our legs, but also use our hands by fixing our legs on the ceiling of the station. (Nie demonstrates how to ride the bicycle using the two different positions). We also usually practice Tai Chi to stretch muscles.

2: A student from St Paul's Co-educational College:

Where does water come from in space, and how do astronauts drink it?

Liu Boming: Water is produced in two forms, one by separating air from cold air to extract condensed water, and the other by processing urine to produce distilled water. Both processes need to remove ionic pollutants and organic matter and add some salt before they can be processed into reclaimed water.

Water has three uses for astronauts. The first is to refill the space suits, which have a lot of tubes inside to hold water to cool down the heat. The water can also be used to produce oxygen for astronauts to breathe and to drink.

To drink water in space takes some technique. For someone who is an astronaut and loves Kung Fu tea, water is precious. So I made a bag of tea and now I'll show you how to drink it in space.

I had to gently squeeze the bag in order to make the right size of a floating water ball and then I can slowly drink it when the ball is floating steadily.