Credit: Photograph courtesy of Purdue University School of Mechanical Engineering and Birck Nanotechnology Center
Mechanical engineers at Purdue University have proven that the same sort of "deterministic chaos" behind the baffling uncertainties of the stock market and long-term weather conditions also interferes with measurements taken with an atomic-force microscope. The engineers also have shown through a series of experiments precisely how much error is caused by the effects of chaos, information that ultimately could be used to help researchers make more accurate measurements. These three images taken with an atomic-force microscope show the three-dimensional shape, or topology, of a flat sheet of a material called highly oriented pyrolitic graphite. The image on the far left shows how the image should look when the tip is oscillating normally. The two other images are examples of errors created when the tip suddenly starts moving chaotically.