Uma abordagem experimental de ondas em cordas utilizando a plataforma Arduino

Abstract

This work aims to develop an experimental apparatus for the study of waves in strings using the Arduino Platform. A bibliographic review is made about Physics Education in Brazil, where emphasis is placed on the experimental approach as a mediator of the teaching-learning process. Regarding the teaching of waves, it relies on the National Common Curricular Base (BNCC) and on the National Curriculum Parameters (PCNs) as a mandatory content both in secondary and fundamental education, respecting the level of education. In this context, several works are found whose objective is to improve the teaching of this content through the experimental approach. A review is made of the use of Arduino as a teaching tool in recent years. To understand the development of the experimental apparatus, concepts and equations related to the content of mechanical waves were approached. The apparatus developed here is similar to a guitar arm. A nylon string is tensioned and vibrated. The value of the tension force is measured by a load cell and the sound wave emitted is captured by a sound sensor. The analysis of this emitted sound wave is made by the SciDAVis Software: the construction of the formed wave is made and the application of a FFT (Fast Fourier Transform). Before analyzing the waveform emitted by the string, the system is calibrated: the load cell is calibrated from a known weight value and the sound sensor captures a sinusoidal sound wave emitted by an audio generator that allows choosing the frequency of that wave. In the signal received, FFT is applied and the same frequency reported by the audio generator is obtained, proving the reliability of the system. From the construction of the sound signal emitted by the string, a wave shape was obtained composed of the superposition of harmonic waves and the application of FFT in this signal resulted in obtaining a frequency spectrum whose values are multiples of the fundamental frequency. This work contributes to the teaching of waves by means of the experimental proposal, as well as to encourage the use of the Arduino platform to teach this content.