This article presents several simple experiments based on changing transverse vibration frequencies in a cantilever beam, when acted on by an external attached mass load at the free end. By using a mechanical wave driver, available in introductory undergraduate laboratories, we provide various experimental results for end loaded cantilever beams that fit reasonably well into a linear equation. The behaviour of the cantilever beam's weak-damping resonance response is studied for the case of metal resonance strips. As the mass load increases, a more pronounced decrease occurs in the fundamental frequency of beam vibration. It is important to note that cantilever construction is often used in architectural design and engineering construction projects but current analysis also predicts the influence of mass load on the sound generated by musical free reeds with boundary conditions similar to a cantilever beam.
The interest in achieving improved acoustical conditions in classrooms has increased in the last years. Some experiments on acoustics phenomena using smartphone applications appear in the recent bibliography. In this paper, we present a proposal for active learning about room acoustics for high school and undergraduate students. Students work on the concepts of reverberation and intelligibility through a set of activities centered on speech communication in the school. For experimental work, they use smartphone applications. At the end of the work, students would be able to suggest some actions to improve acoustic comfort in school.
We present some lab science experiments that are intended to be performed by undergraduate university students of scientific and technological disciplines. We come out with an experimental study of waves in Kundt’s tube by varying the absorption characteristics of its closed end. The measurement of the resonant frequencies permits to determine the speed of sound in the tube. The impedance tube-standing wave method (ISO-10534-1) is applied to study the normal absorption coefficient of acoustics insulators. The setup includes basic lab equipment available in the undergraduate laboratory: a tube, a speaker, a microphone, a digital function generator and an oscilloscope.
We present a proposal for active learning about environmental acoustics and room acoustics for high school and undergraduate students. Students work on the concepts of sound pressure level and reverberation time through a set of activities centred on speech communication in the school. For experimental work, they use smartphone applications for sound measurement. At the end of the work, students would be able to suggest some actions to improve the acoustic comfort in school. The students’ interest increases as they focus on their own experience. Moreover, they can apply and test the solutions that they propose.
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