Where does clapping sound from?

• Researchers used real-life and experimental data to understand the sound of clapping.

• The sound originates from a Helmholtz resonator, a device that produces sound by trapping and vibrating air within a cavity.

• The air enclosed between palms is the cavity in a Helmholtz resonator.

• Experiment involved depositing dry baby powder into a palm cavity to make airflow visible.

• The first and strongest jet of air was heard at the first impact of two palms, dissipating after a few secondary and tertiary jets.

• Clapping sound dissipated in about 10 ms.

• Different palm shapes made different sounds, with frequency increasing as shape changed from cupped to palm-palm to palm-finger contact.

• Clapping had two distinct frequency peaks: a lower one associated with the Helmholtz resonator and the higher one with sound from finger grooves.

• Real-life sound peaks varied from theory due to different clapping styles and finger bends.