Why's there chatter in my Himalayan singing bowl?

A Himalayan singing bowl operates much in the same way as a wine glass—slide your fingertip, or a wooden stick called a puja, around its rim to hear its soothing tones. The bowls, which originated in the Tibetan mountain region and are made of metal alloys, have been used for meditation and worship since around 500 BCE, but have found recently new audiences in contemporary music. While the complex stick-slip motions responsible for "chatter," or rapid knocking sounds, have been extensively