A staff member introduces a video to visitors at the Wuhan Institute of Physics and Mathematics of the Chinese Academy of Sciences (CAS) in Wuhan, capital of central China's Hubei Province, May 20, 2018. The 14th CAS "Public Science Day" was held on May 19 and 20. (Xinhua/Xiong Qi)

Staff members introduce an equipment to visitors at the Wuhan Institute of Physics and Mathematics of the Chinese Academy of Sciences (CAS) in Wuhan, capital of central China's Hubei Province, May 20, 2018. The 14th CAS "Public Science Day" was held on May 19 and 20. (Xinhua/Xiong Qi)

A staff member introduces an equipment to visitors at the Wuhan Institute of Physics and Mathematics of the Chinese Academy of Sciences (CAS) in Wuhan, capital of central China's Hubei Province, May 20, 2018. The 14th CAS "Public Science Day" was held on May 19 and 20. (Xinhua/Xiong Qi)

Children visit the Chengdu Branch of the Chinese Academy of Sciences (CAS) in Chengdu, capital of southwest China's Sichuan Province, May 20, 2018. The 14th CAS "Public Science Day" was held on May 19 and 20. (Xinhua/Liu Kun)

A staff member introduces an equipment to visitors at the Wuhan Institute of Physics and Mathematics of the Chinese Academy of Sciences (CAS) in Wuhan, capital of central China's Hubei Province, May 20, 2018. The 14th CAS "Public Science Day" was held on May 19 and 20. (Xinhua/Xiong Qi)

A volunteer displays adsorption of carbon at the Chengdu Branch of the Chinese Academy of Sciences (CAS) in Chengdu, capital of southwest China's Sichuan Province, May 20, 2018. The 14th CAS "Public Science Day" was held on May 19 and 20. (Xinhua/Liu Kun)

A child experiences a telescope at the Chengdu Branch of the Chinese Academy of Sciences (CAS) in Chengdu, capital of southwest China's Sichuan Province, May 20, 2018. The 14th CAS "Public Science Day" was held on May 19 and 20. (Xinhua/Liu Kun)