There are bubbles in your joint fluid that POP! when a joint is "cracked."
Via Phys.org
Using a mathematical model alongside a geometrical representation of the joint, experts from Paris' Ecole Polytechnique and Stanford University in the United States simulated the events leading up to the crack.
"The sound that is generated when one cracks his or her knuckles is due to the partial collapse of a cavitation bubble that's in the fluid in the joint," explained Abdul Barakat, a professor at the Ecole Polytechnique.
"It could be multiple bubbles, but we showed that the collapse of a single bubble is sufficient to give you the signature sound you get," he told AFP by phone.
Every joint in my body makes noise.
Image via Vecteezy
