Resonance Column II AIM

Resonance, 2011

The experiments of resonance tube method and resonator method are performed without using the tuning fork. To generate audio vibrations, a speaker connected with an AFO (Audio Frequency Oscillator) is employed. The experiments thus becomes very easy and simple. More observations can be taken depending on the length of the tube. The intensity of the sound can be controlled using AFO. The results are reliable.

Physics Education, 1996

The principle of resonance can by utilized to determine the wavelength of a sound wave. Sound waves are produced by the compression of a substance by vibrations caused by objects such as vocal cords, guitar strings, organ pipe, loud speaker, and so forth (Physics of Sound, para. 1). A resonance frequency exists when a system is driven by its natural frequency. Pendulums and swings demonstrate only one natural frequency (Spalding, 2010, pp. 3-15).

The aim of this lab was to obtain the speed of sound in air using properties of standing waves. Standing waves are created when travelling waves are reflected and superpose. Given this, if sound waves are sent into a tube with a closed boundary, then the first harmonic formed results in an antinode at the open end of the tube. This way the wavelength of the wave could be obtained and given that the frequency of sound waves were known, the speed of sound could be obtained using the equation c = f λ.

Applied Sciences

A theoretical analysis and experimental investigation of the influence of gas pressure on resonance properties, namely, the quality factor and resonance frequency, of a T-shaped quartz tuning fork (QTF) is reported here. Two configurations are considered: a bare QTF, and a QTF coupled with a pair of resonator tubes (spectrophone). In both configurations, the effect of air on resonance frequency due to the additional inertia on prong motion and the influence of air damping on the quality factor, were analysed. By comparing the bare QTF and the spectrophone results, the effect of pressure on the acoustic coupling between the QTF and the tubes was theoretically modelled and then validated. The results show that acoustic coupling is strongly influenced by air pressure, leading to a shift of resonance frequency and a decrease in the quality factor up to 24%.

OBJECTIVE: In this study, we evaluated used aluminum tuning forks (TFs) for fundamental frequencies (FF), overtones, and decay times. MATERIALS and METHODS: In total, 15 used (1 C1, 11 C2, and 3 C3) and 1 unused (C2) TFs were tuned, and the recorded sound data were analyzed using the Praat sound analysis program. RESULTS: It was found that FFs of the recorded sounds produced by the used C2-TFs presented a high variability from 0.19% to 74.15% from the assumed FFs, whereas this rate was smaller (1.49%) in the used C3-TFs. Further, decay times of the used C2-TFs varied from 5.41 to 40.97 s. CONCLUSION: This study, as the first of its kind in the literature, reported that some of the used aluminum TFs lost their physical properties that are important for clinical TF tests. It could be said that this is a phenomenon related to metal fatigue, which is common in aluminum products due to the cyclic load.

The Physics Teacher, 2015

Atypical two-tine tuning fork is barely audible when held vibrating at an arm's length. It is enough, however, to touch its base to a table or, better, to a resonance box and the emitted sound becomes much louder. An inquiring student may pose questions: Why is a bare tuning fork such a weak emitter of sound?What is the role of the resonance box?Where does energy connected with larger intensity of emitted acoustic waves come from?

American Journal of Physics, 2009

Objective: The purpose of this experiment is to measure the speed of sound in air by exploiting standing wave and resonance effects in longitudinal waves. Equipment: Tuning forks (256 Hz, 426Hz, 512 Hz, 1024 Hz), rubber striker block, resonance tube apparatus. Theory: We have already examined the theory of standing waves and resonance in transverse waves (Standing Waves on a String). In transverse waves the displacement of the medium through which the wave propagates is perpendicular to the direction of wave travel. Electromagnetic waves and waves on strings are examples of transverse waves. In longitudinal waves, the displacement of the medium through which the wave propagates is parallel to the direction of wave travel. Sound waves are a prominent example of longitudinal waves.

The Journal of the Acoustical Society of America, 2012

The need to keep long wind musical instruments compact imposes the bending of portions of the air column. Although manufacturers and players mention its effects as being significant, the curvature is generally not included in physical models and only a few studies, in only simplified cases, attempted to evaluate its influence. The aim of the study is to quantify the influence of the curvature both theoretically and experimentally. A multimodal formulation of the wave propagation in bent ducts is used to calculate the resonances frequencies and input impedance of a duct segment with a bent portion. From these quantities an effective length is defined. Its dependence on frequency is such that, compared to an equivalent straight tube, the shift in resonance frequencies in a tube with bent sections is not always positive, as generally stated. The curvature does not always increase the resonances frequencies, but may decrease them, resulting in a complex inharmonicity. An experimental measurement of the effect of the curvature is also shown, with good agreement with theoretical predictions.