Li Rubing (center), curator of an ammeter museum in Taizhou, Jiangsu province, introduces students to a Japanese-made ammeter on May 19. It was the first time for the students to learn about traditional measuring methods and devices, which were once closely connected with people's daily lives. The most precious and time-honored piece that the museum has is an ammeter made in the United Kingdom in 1905. [Photo/CFP]