Young students experience the pulley facility at the Tianjin Science and Technology Museum in Tianjin, north China, May 19, 2012. A ceremony was held in the museum on Saturday to launch the 26th Tianjin Science and Technology Week. (Xinhua/Yue Yuewei)

Children pose for photos in front of the rocket models at the Tianjin Science and Technology Museum in Tianjin, north China, May 19, 2012. A ceremony was held in the museum on Saturday to launch the 26th Tianjin Science and Technology Week. (Xinhua/Yue Yuewei)