Scientists have identified the reason behind the familiar static shock that can occur when petting a cat. For the first time, a team from Northwestern University has revealed the mechanisms responsible for this phenomenon.
According to Professor Laurence Marks, petting a cat generates static electricity due to differences in the forces acting on the fur. “If you put your hand on a cat, you don’t get an electricity charge. But if you stroke the fur, you do,” he explained.
The research shows that when a hand glides over a cat’s fur, the front and back areas of the hand experience differing forces. This disparity results in the buildup of electrical charges, leading to the static shock commonly felt during such interactions.
Marks elaborated, “Just having different deformations — and therefore different charges — at the front and back of something sliding leads to current.” The findings were published this week in the journal Nano Letters.
Static electricity has fascinated scientists since it was first documented in 600 BC by the Greek philosopher Thales of Miletus, who noted that rubbing amber with fur attracted dust. While it has long been recognized that rubbing induces a static charge in insulating materials like fur, a complete understanding of the process was lacking until now.
Marks and his student researchers began their investigation in 2019, studying how rubbing two materials together causes tiny surface deformations that generate electricity. Despite challenges posed by the COVID-19 pandemic, the team continued their research.
Marks noted, “We’d done some work on tribology, which involves friction, and we’d also explored flexoelectricity, where bending generates voltage. I realized we could combine these concepts to better understand triboelectricity.”
The researchers have developed a new model to calculate electrical currents using a principle known as “elastic shear.” This occurs when a material resists sliding, causing electrical charges to move and accumulate.
While the phenomenon may be amusing in domestic settings, static electricity can pose serious risks in industrial environments, leading to fires and explosions, or affecting the consistency of powdered pharmaceuticals. The researchers hope their findings will lead to better prevention and control measures. “If we understand, we can prevent; we can control,” Marks concluded.
Related Topics
Is Neutering Male Cats Beneficial for Their Health?
