By John Dodge

CHICAGO (CBS) — Brittni arrives at the gym precisely at 5 a.m., ready to hit the cardio machines before work.

Every day, she needs to allow about five minutes to untangle her ear buds before she can listen to her workout playlist.

The day before she had placed them inside her bag, perfectly coiled in a neat oval.

It seems like a mystery. It is certainly frustrating.

Why must Brittni be tortured with this madness everyday?

It’s all about physics.

Researchers found that strings similar in size to ear buds were that perfect for “spontaneous tangling.”

It happens when you put those ear buds back in your gym bag or purse and allow them to move about inside.

(Credit: National Academy Of Sciences)

(Credit: National Academy Of Sciences)

University of California at San Diego Physicists Dorian M. Raymer and Douglas E. Smith did the research back in 2007, around the time that the sixth-generation iPod was released.

Raymer and Smith placed a string in a box and rotated it once per second for 10 seconds and observed the spontaneous knotting. (Photo above). They did variations of this experiment–changing things like box size, tumbling speed and string size–nearly 3,500 times.

“We performed experiments in which a string was tumbled inside a box and found that complex knots often form within seconds,” the researchers wrote.

They found that the odds of tangling increased to 50-50 as the length of the string increased toward two meters.

According to Apple, the length of iPod ear buds are 1.395 meters.

Ear buds that are slightly longer than the iPod are even more likely to tangle spontaneously.

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