Determination of Young’s modulus of elasticity using a smartphone

In the present work, a didactic activity proposal is presented for undergraduate students of Physics and Engineering courses, aiming at determining the elasticity module of steel and aluminum, using rods constituted by these metals and a smartphone to obtain the values of the resonant frequencies of the harmonics that are established in them. The theoretical foundation considered the oscillation of these rods submitted to simple flexions, with free ends. The motion dynamics equation was solved to obtain the locations of the nodes, the frequencies of the harmonics, and the relationship with the Young’s modulus. The practical tests employ simple measurement techniques, highly available equipment and very low cost. The results demonstrate the feasibility of the proposal, which, in addition to exploring teaching through multiple representations, has a strong playful and sensory appeal, including for students with hearing disabilities. There is also an applicability bias for high school.

Keywords
Physics teaching; natural frequency; resonance; modulus of elasticity; rods; smartphone