Chapter 3

Sound

The following Topics and Sub-Topics are covered in this chapter and are available on MSVgo:

Introduction

Sound, like electricity, heat, and light, is a source of energy. Let’s explore the various sources of sounds like a whistle. A bell makes a constant ringing noise when hit. Place the finger on the bell when you’ve rattled it, rather than simply reacting to it. Is it vibrating towards you? The trick to the tone is this. Guitars and percussion show that off even further. When you pluck it, you can feel the wires vibrating. The echo ceases until the bell or the instrument stops vibrating. 

A portion of a wave is mirrored, and a portion of the wave is sent over the barrier as it hits the boundary between two mediums. The difference between the two media determines the sum of contemplation. 

The reflection of sound waves off the surfaces will create either an echo or a reverberation. A reverberation is typical in a small space with 17 meters or less in height, width, and volume. 

Echoes are triggered by sound waves bouncing off of each other. Reverberations are not the same as echoes. When a reflected sound wave arrives at the ear longer than 0.1 seconds after the main sound wave, it is called an echo. If the time between the arrivals of the two sound waves is longer than 0.1 second, the first sound’s impression would have disappeared. In this situation, the second sound wave would be heard as a separate sound rather than a continuation of the previous. Instead of reverberation, there would be an echo.

  • This is a vibration effect dependent on the sound wave’s intensity. The sound is said to be noisy if the amplitude of the sound wave is high. 
  • That is equal to the square of the vibration’s amplitude. The loudness of the echo will be quadrupled if the amplitude of the sound wave is multiplied. 
  • It is measured in decibels (dB). 
  • Human ears interpret noises over 80 decibels as noise. 

Its relationship to its amplitude defines a sound wave’s loudness. A sound wave’s loudness is defined by its relationship to its amplitude; all waves have a definite amplitude. For example, in a calm ocean, a wave’s height would be less than 1 foot, while good surfing waves will be 10 feet or more in amplitude. The amplitude will exceed 40 to 50 feet during a storm.

  • This is determined by the magnitude of the waves’ vibrations. 
  • The tone is shrill and has a loud pitch if the level of vibration is greater. On the other side, if a sound is said to have a lower pitch, it means that it vibrates at a lower level. 
  • A bird creates a high-pitched sound, while a lion’s scream is low-pitched. 
  • The pitch of a woman’s voice is greater than that of a man.

All sounds are created by the movements of molecules that the sound flows through. 

When a drum or a temple bell is struck, for example, the item vibrates. Air molecules shift, and sound is created as a consequence of these vibrations. 

As the vibration amplitude is increased, a quieter sound is made, and when the vibration frequency is increased, a higher-pitched sound is detected. In reality, an organism’s capacity to hear is dictated by the strength of vibrations. 

  • Forced vibrations
    Forced vibrations are the motions of a body that arise under the impact of an external periodic force operating on it. When the stem of a vibrating tuning fork is pushed to the top of a table, the tabletop vibrates at the pace of the tuning fork.
  • Resonance
    Forced waves are a subset of resonance. As the frequency of an externally exerted periodic force equals the normal frequency of a muscle, the body begins to vibrate with greater amplitude. This effect is known as resonance, and large-amplitude vibrations are referred to as resonant vibrations.

In this chapter, we learned about the basics of sounds. We learned important concepts of sound like forced natural vibrations and sound quality.

  1. Mention a list of physical causes that have an effect on sound transmission.
    Turbulence in the atmosphere
    Sound waves disperse due to velocity changes in the medium if the environment in which they are moving is unstable.
    Gradient of wind
    The sound that travels with the wind bends downwards, and the sound that travels towards the wind bends upwards.
    Gradient of temperature
    In a humid atmosphere above the earth’s surface, sound waves propagate further. Sound waves are refracting upwards in this field. The refraction would be downwards if the temperature decreases at higher altitudes.
  2. What feature of sound is influenced by temperature change?
    Temperature fluctuations influence the wavelength of sound. The wavelength of sound is influenced by temperature fluctuations.
  3. In sonography, what waves are used?
    Sonography makes use of ultrasonic waves.

  4. What exactly do you mean when you say “echo”?
    Echo is a delayed representation of the sound that enters the audience after the actual sound.

  5. What are the three different forms of sound?
    Mechanical waves are classified into three categories: transverse waves, longitudinal waves, and surface waves.

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