Ribbon Curling Secret

The physics behind ribbon curling has been revealed.

20:10 18 March 2016

Scientists have provided an explanation as to why ribbon curls when we run a scissor blade down one side of it.

 

The UK-based team said that the explanation lies on the blade’s sharpness, the tension applied to the ribbon and the speed it moves. The ribbon’s outermost side is deformed as the ribbon bends around the blade, producing curls. Sharper blades and slower movement make tighter curls but the pulling force has an ideal strength.

 

Senior author Anne Juel, from the University of Manchester, said: "It takes a certain amount of time for the stress in the ribbon to relax, and the irreversible deformation to take place."

 

"The first part that's going to start to yield is the outermost part of the ribbon, because that's the point where the stress is going to be highest. And then as you apply larger loads, the yield is going to infiltrate deeper and deeper inside the ribbon."

 

"So the tightest curl will be obtained when you manage to apply a load that will bring yield to exactly half the thickness of the ribbon.”