Experiment to Clarify Ancient Physics Discovery Yields More Questions

In approximately 600 B.C., the Greek philosopher Thales of Miletos discovered that rubbing certain materials together, such as amber and wool, can cause both to become electrically charged, one positive and one negative. This phenomenon is useful for several industrial processes, including printing and filtration, and has sparked much interest and study. Still, scientists cannot fully explain how rubbing-induced charge transfer occurs or how that transfer affects surrounding objects.