Have you ever wondered how snapping your fingers works? What makes that satisfying click sound? And could you snap your fingers while wearing a metal glove like Thanos in Avengers: Infinity War?
A team of researchers from Georgia Tech decided to investigate the physics of finger snapping, inspired by the movie scene where the supervillain snaps his fingers and obliterates half of the universe’s life. They used high-speed video to capture the ultrafast motion of snapping fingers and found some surprising results.
According to their study, published in Journal of the Royal Society Interface, a finger snap produces one of the fastest rotational motions known in the human body, almost as fast as some professional baseball pitchers’ arms. The middle finger rotates at a rate up to 7.8 degrees per millisecond, nearly what a professional baseball pitcher’s arm can achieve, and accelerates almost three times as fast as pitchers’ arms.
A finger snap lasts only about seven milliseconds, which is roughly 20 times as fast as the blink of an eye. In that brief moment, there are three components to the snapping finger sound: the friction or sliding sound between the thumb and middle finger, the impact sound from the middle finger colliding with a groove created by the ring finger and the palm, and the pop sound from the rapid compression and decompression of air.
The researchers found that the friction between the thumb and middle finger is crucial for storing energy before it’s suddenly released, and that the compressibility of the finger pads increases the contact area and friction between them. They also discovered that the sound of snapping fingers is influenced by the material and rigidity of the fingers, as well as the shape and size of the palm.
To test this, they tried snapping with fingers covered by hard thimbles, high-friction rubber or low-friction lubricant. They found that none of these materials could produce a proper snap, indicating that bare fingers have a level of friction ideal for a speedy snap.
So what does this mean for Thanos? The researchers concluded that his snap would have been a dud, since his metal glove would have prevented him from creating enough friction and compressibility to make a loud snap. No superheroes needed: Physics saves the day.
As one of the researchers, biophysicist Saad Bhamla, said: “We were just having fun with it. We were just curious.” Maybe you can try some snapping experiments of your own and see if you can beat the world record for most snaps in a minute (437 snaps). Just don’t expect to wipe out half of all living things with a snap of your fingers. That’s pure fiction.
Relevant articles:
– Why Does it Make a Noise When You Snap Your Fingers?, Only Silent
– How do fingers snap? Physics of finger snapping revealed, Cosmos, 17 November 2021
– New high-speed video reveals the physics of a finger snap, Science News, 16 November 2021
– Science behind the finger snap, St George & Sutherland Shire Leader, 18 November 2021