Musical pillars made of solid granite

The Vitthala Temple in the south Indian city of Hampi is more than 500 years old. The image here shows its most curious feature—numerous pillars, each of which includes separate columns that sound musical notes when struck with a finger. Different columns in a pillar produce sounds of different frequencies. Moreover, several multi-columned pillars make sounds similar to specific Indian musical instruments such as the ghanta (bell), mridanga (percussion), or veena (strings). Well known for centuries, the musical pillars are only now beginning to be studied scientifically. Anish Kumar of the Indira Gandhi Center for Atomic Research in Kalpakkam, India, and colleagues took the first steps to characterize the columns: The physicists applied three techniques to learn about the structure of the columns and also analyzed recordings of generated sound. In situ metallography showed the granite to have typical microstructures; both lowfrequency ultrasound and impact-echo testing revealed all the columns to be solid shafts. From those studies and spectral analyses, the researchers conclude that the pillars’ sounds arise from the flexural mode of vibrations. Next on their agenda is to study how the columns can be excited by just the tap of a finger. (A. Kumar et al., J. Acoust. Soc. Amer. 124 , 911, 2008 http://dx.doi.org/10.1121/1.2945170 .)