This TV grab taken on June 20, 2013 shows female astronaut Wang Yaping, one of the three crew members of Shenzhou-10 spacecraft, injecting air bubbles into a water ball in space during a lecture to students on Earth aboard China's space module Tiangong-1. A special lecture began Thursday morning, given by Wang Yaping aboard China's space module Tiangong-1 to students on Earth. (Xinhua)