A beam balance is analyzed as a model that describes Weber's law. The mathematical derivations of the torques on a beam balance produce a description that is strictly compatible with that law. The natural relationship of the beam balance model to Weber's law provides for an intuitive understanding of the relationship of Weber's law to sensory and receptor systems. Additionally, this model may offer a simple way to compute perturbations that result from unequal effects on coupled steady-state systems. A practical outgrowth from this work is that a relatively simple mathematical description models sensory phenomena and may aid in the understanding of sensory and receptor systems.