Many of us are guilty of doing it. Some hate it. Rumor has it that it causes arthritis. The sounds that it makes has long been a mystery to science. Not anymore! Researchers have recently found the source of the sound caused by finger cracking, a long standing question in the scientific community.
Where does the little annoying noise caused by the crackling of fingers come from? This a priori harmless question has been a source of debate within the scientific community for more than 60 years. But researchers at the Ecole Polytechnique in France and Stanford University in the United States, who published a study on March 28 in the journal Scientific Reports, claim to have found the answer. The “crack” actually comes from the bursting of microscopic bubbles present in the fluid of the finger joint.
“The bursting of one of these bubbles is enough to produce the noise”
This hypothesis had already been formulated in 1971 by Dr. Unsworth, but it was later been called into question. Other researchers argued that after a crack of fingers, the bubbles remained in the fluid of the joints, which, according to them, invalidated the hypothesis according to which it was the bursting of these bubbles that was at the origin of the “crack”. Then, in 2015, a new study had argued that this noise actually came from the very formation of bubbles.
But the researchers at the French Ecole Polytechnique and Stanford University have decided: “The bursting of one of these bubbles is enough to produce the noise,” said Professor Abdul Barakat, who participated in the study.
This is the first time that a research on the subject is based on a mathematical model: until now, the researchers had only worked by observation. “After the writing of this study, my daughter has tried herself, and now she is cracking her fingers,” said Professor Barakat, himself a fan of this practice. A habit that does not worry him at all: contrary to the rumor, it does not cause arthritis!