Audible And Inaudible Sounds

Key Notes :

Definition of Sound:

  • Sound is a form of energy that travels through a medium (such as air, water, or solids) in the form of vibrations.
  • It is produced when an object vibrates, causing the surrounding medium to vibrate as well.

Audible Sounds:

  • Audible sounds are the sounds that can be heard by the human ear.
  • The frequency range of audible sounds is 20 Hz to 20,000 Hz (20 kHz).
  • Most humans, especially younger people, can hear sounds within this frequency range.

Inaudible Sounds:

  • Inaudible sounds are those that cannot be heard by the human ear.
  • They are categorized into two types:
    • Infrasonic sounds: Frequencies below 20 Hz (e.g., vibrations caused by earthquakes).
    • Ultrasonic sounds: Frequencies above 20,000 Hz (20 kHz) (e.g., sounds used by bats, dolphins, and ultrasound machines).

Examples of Audible and Inaudible Sounds:

  • Audible sounds: Music, human speech, animal sounds, and sounds produced by musical instruments.
  • Infrasonic sounds: Natural phenomena like earthquakes, volcanoes, and waves crashing.
  • Ultrasonic sounds: Dog whistles, medical ultrasounds, and sonar systems.

Applications of Inaudible Sounds:

  • Ultrasonic waves are used in medical imaging, such as ultrasounds, to view internal organs.
  • Sonar (Sound Navigation and Ranging) uses ultrasonic waves for underwater navigation, object detection, and mapping.
  • Infrasonic waves are used in the study of natural disasters like earthquakes and volcanoes.

Human Hearing Limitations:

  • The ability to hear high-frequency sounds decreases with age.
  • Animals like dogs, bats, and dolphins can hear ultrasonic sounds that humans cannot.

Importance of Frequency and Pitch:

  • Frequency is the number of vibrations per second, measured in Hertz (Hz).
  • Pitch refers to how high or low a sound seems to a listener. Higher frequencies correspond to higher pitches.

Factors Affecting Audibility:

  • Intensity of sound: Sounds that are too faint (low intensity) may not be heard, even if they are within the audible frequency range.
  • Hearing impairments: Certain conditions can affect a person’s ability to hear sounds within the normal audible range.

Everyday Applications:

  • Devices like hearing aids amplify audible sounds to help those with hearing loss.
  • Ultrasonic sensors are used in car parking systems and burglar alarms.

Summary:

  • Audible sounds are within the range of human hearing, while inaudible sounds fall outside this range.
  • Understanding audible and inaudible sounds is crucial for applications in technology, medicine, and environmental science.

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