How do whips make that crack sound

It takes a dexterous hand to coax a whip to crack. Now researchers report that they have discovered the mechanism responsible for the startling sound. It has long been thought that the crack results from the tip of the whip traveling fast enough to break the sound barrier and create a sonic boom. But the new findings suggest otherwise. Apparently, it's the loop in a whip that is the real noisemaker.

Though by no means a master whip cracker, Alain Goriely of the University of Arizona was nonetheless intrigued by the phenomenon and set out to study it at a theoretical level.

However, those observations created a puzzle - the tip was moving at twice the speed of sound Mach 2 when the crack was created. Even though those parts are moving twice as fast, it is the loop itself that generates the sonic boom," Professor Goriely said. The idea that the tip travels twice as fast as the loop is like how the uppermost point on a car tire is traveling at twice the speed of the car for just an instant.

The tapering of a whip makes a loop traveling along it speed up by a factor of ten. Your email address will not be published. Notify me of follow-up comments by email. Notify me of new posts by email. Skip to content MechStuff ''Making stuff… Simpler''. Toggle navigation. What is a S onic boom? So how does whip produce loud sound? Well, there's a few answers to this. It's claimed that the whip crack is actually a sonic boom.

This sonic boom is supposed to appear when the very tip of the whip moves at faster than the speed of sound, and so breaks the sound barrier. The speed of sound is pretty close to around to 1, kilometres per hour, so how can you move the tip of a whip at that speed besides the fact that you've got a long lever arm?

One theory is based on the fact that the whip is tapered from the handle to the tip. When you move the whip handle, you start a wave heading towards the tip.