This post certainly has nothing to do with science. A number of years ago (7 or more), the urban myth spread in Japan that you could keep away cats by putting out PET bottles filled with water. I didn't realize that cats were that big of a problem, but around that time you started to see water-filled PET bottles everywhere.This myth has been proven false repeatedly, but water-filled PET bottles are still easy to find on a stroll down almost any street.
