Young's modulus determination of elastomeric materials using capacitance measurement

Young's modulus is addressed in the introductory courses of physics as a constant. In metals, for a large amplitude of stresses, this property has a constant behaviour. Unlike metals, elastomers do not present a constant Young's modulus, but depend on the strain of the material. This work presents an experimental teaching practice of Young's modulus determination of elastomers under small mechanical stresses by means of capacitance measurements. The capacitances were measured in capacitors constructed with dielectrics made with elastomers. An electronic circuit capable of producing electrical voltages from variations of the order of pF in the capacitors was used. The results show that for low levels of stress, Young's modulus has nonlinear increases with the applied mechanical stress. The methodology employed in this work can be adapted for other experiments with didactical aims.