16 / 18 : Visit of Questacon with my friend Dai Chaoqing and his family, Canberra, 30.03.2014: Questacon20140330 124425
The strings of the pendulums had different length.
The strings of the pendulums had different length. The different oscillation frequencies caused nice waves of the balls.
- 2014 Mar 30 12:44:25
