Since its invention, the atomic force microscope has permitted high-resolution imaging at the subnanometer level. Recently, when scientists introduced the microscope to a liquid environment, the resolution improved to the atomic level. Aside from improving resolution, advantages of performing measurements in liquid included eliminating capillary forces and providing a natural environment for biological surfaces. Kenichiro Koga and X.C. Zeng of the University of Nebraska at Lincoln have discovered that when the tip of the microscope makes a scanning motion over the sample, it sometimes takes a hopping motion because of the way the water molecules are layered. This hopping motion, they suggest, may affect a sample's image quality.