jnd had to do with differences in weight. He stated that the jnd is the "minimum amount of difference between two weights necessary to tell them apart". He found that the finest discrimination between weights was when they differed by 8–10%. For example, if you were holding a 100 g block, the second block would need to weigh at least 108 g in order to be distinguishable. Weber also suspected that a constant fraction applied for all senses, but is different for each sense. When comparing the differences in line length, there must be at least 0.01 difference in order to distinguish the two. When comparing music pitch, there must be at least 0.006 vibrations per second difference. So for every sense, some increase in intensity is needed in order to tell a difference. Weber's Law Weber’s Law, as labeled by Gustav Theodor Fechner, established that sensory events can be related mathematically to measurable relative changes in physical stimulus values. : amount of stimulation that needs to be added to produce a jnd : amount of existing stimulation ( from the German Reiz, meaning stimulus) : constant (different for each sense) Weber’s law is invalid when the stimulus approaches the upper or lower limits of a sensory modality. Fechner took inspiration from Weber’s Law and developed what we know today as Fechner’s Law, claiming that there was a logarithmic relation between stimulus intensity and perceived intensity. Fechner’s Law was more advanced than Weber's Law, partly because Fechner had developed new methods for measuring just-noticeable differences in different sense modalities, making the measured results more accurate. Experimental Psychology For most of his career, Weber worked with his brothers, Wilhelm and Eduard, and partner Gustav Theodor Fechner. Throughout these working relationships, Weber completed research on the central nervous system, auditory system, anatomy and function of brain, circulation, etc., and a large portion of research on sensory physiology and psychology. The following items are part of Weber’s contributions the experimental psychology: Experimental Wave Theory Studied flow and movement of waves in liquids and elastic tubes. Hydrodynamics Weber discovered laws and applied them to circulation. In 1821, Weber launched a series of experiments on the physics of fluids with his younger brother Wilhelm. This research was the first detailed account of hydrodynamic principles in the circulation of blood. Weber continued his research on blood and in 1827, he made another significant finding. Weber explained