Acoustic resonance

rbalzan79(74)

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First of all my respectful greetings to all the Hive.blog community, in this opportunity we will continue relating to the phenomenon of sound, and with this delivery we will culminate with our wonderful journey on some important aspects of such an essential phenomenon for man as it is the sound.

Introduction

So far we have shown my dear friends that when our ears are able to perceive a sound it is because these sound waves are in the audible fraction for humans and it was expressed at the time, the same is between 20 to 20,000 Hz (hertz or Hertz).

Moreover, dear friends, also when we listen to a sound we are audible witnesses of the generation of a vibratory movement, otherwise those longitudinal pressure waves capable of disturbing the material or elastic medium through which these waves propagate until they reach our natural audible system, that is, our ears, would not be generated.

The analysis of the propagation of sound allowed us to relate to other types of phenomena intrinsic to this expansion such as reflection, absorption, transmission, diffraction, refraction, as well as to the entire sound or acoustic spectrum, where we find other waves imperceptible to our ears, such as infrasound and ultrasound, both of which have a great influence on our lives.

We have also learned in a general way about the phenomenon of resonance and the natural frequency of oscillation, and now we will focus on the acoustic or sonorous resonance itself.

Acoustic resonance

In many occasions we are witnesses of this type of acoustic phenomenon, for example, there are sound waves emitted by certain sources that when impacting with some objects make their component particles vibrate, therefore, we can express that sound waves can carry out a resonance when in contact with any body, object or mechanical system which is in our environment, as we can see below in the following figure 1.

_{Figure 1. Resonance of a given system (vehicle), caused by sound waves}

Another example that we can describe is when the sound waves emitted by a sound source placed near our houses make some glass or crystals of our windows or any other component of the structure of our home vibrate, and it is because some of these sound waves have a frequency very similar or equal to the natural frequency of vibration of the aforementioned components of our homes, and thus an increase in the amplitude of the oscillations or vibrations is generated.

It is important to highlight that only those objects whose frequency of oscillation or natural vibration approaches or coincides with the frequency and length of the emitted sound waves can enter into resonance, this means that not all objects enter into resonance due to the impact of sound, this explains that not all bodies, objects or systems have the same frequency or natural oscillation capacity.

Similarly we can say that a resonance process has the ability to generate sound, for example, by rubbing the edge of a glass with our finger and doing so periodically, we make or cause all the component particles of the same vibrate as we are transmitting energy, and thus, we achieve that the glass reaches its natural frequency of oscillations or vibrations, and also generates audible sounds to our ears, this action can be seen in Figure 2 below.

_{Figure 2. Acoustic resonance and sound generation}

Another interesting example can be found in wind instruments such as trumpets, and this occurs when we can match the natural frequency of oscillation or vibration of the air located inside the instrument with the frequency of oscillation of our lips and thus we can emit a certain harmonic musical note, and thus, an adequate acoustic resonance.

Conclusion

With this article we were able to see how the phenomenon of sound continues to allow us to know other phenomena originated around us as is the case of acoustic resonance, where the sound on impact with any object, body or mechanical system cause them to oscillate or vibrate, and this occurs because the frequency of these sound waves are close or equal to the natural frequency of oscillation or vibration of the bodies mentioned above, therefore, this causes the phenomenon of acoustic resonance to develop in this case.

As generally occurs with the different natural phenomena we have analyzed, resonance also has important applications in our daily activities, for example, in the area of construction it is implemented to determine the resistance capacity of the structures and thus measure how resistant they could be when facing any natural phenomenon, and thus to avoid some kind of catastrophe, and this is because these materials of these constructions have their natural frequency of oscillation, and thus, the possibility of resonance that could lead to its collapse.

Until another installment, my dear Hive.blog readers.