Hand clapping is ubiquitous habits for people throughout time and cultures, serving many alternative functions: to indicate approval with applause, for example, or to maintain time to music. Acousticians usually use a hand clap as an inexpensive substitute for expensive tools to make acoustic measurements in structure. Whereas the essential bodily mechanism is easy, the underlying bodily mechanisms are much less well-understood.

A new paper printed within the journal Bodily Evaluate Analysis gives experimental help for the speculation that hand clapping primarily acts like a Helmholtz resonator—akin to the hum generated by blowing throughout the highest of a bottle, or the hiss one hears when holding a conch shell to 1’s ear.

In 2020, engineers Nikolaos Papadakis and Georgios Stavroulakis, each on the Technical College of Crete, recruited 24 college students to clap their arms as soon as in several venues, various their hand configurations in 11 other ways—altering the angle of the arms with respect to 1 one other, for example, or altering what number of fingers of 1 hand overlapped with the fingers or palms of the opposite.

The outcomes: The hand configuration that produced the loudest clap—85.2 dB—consisted of holding the arms 45 levels to one another with the palms partially overlapping. If one had been extra involved in producing a richer vary of frequencies, it is higher to make sure one’s palms are fully overlapping and formed right into a dome, enclosing a pocket of air. (The identical 45-degree hand orientation applies.) The second configuration did not produce as a lot of a shock wave as the primary. Papadakis and Stavroulakis concluded that holding one’s arms flat or in a dome whereas clapping produces the equal of a Helmholtz resonator.