Learn the key Difference Between Audible and Inaudible Sound Class 8. Explore frequency ranges, infrasonic vs. ultrasonic sounds, and examples.
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Understanding Audible and Inaudible Sound
Have you ever wondered why we can hear a buzzing bee but not the waving of our hands? Or why dogs seem to react to noises that we can’t hear at all? The world is full of vibrations, but our ears are only tuned to a specific range.
In this post, we’ll break down the difference between audible and inaudible sound class 8 students need to know for their science exams.
What is Audible Sound?
Sound waves that the human ear can detect are called audible sounds. For a sound to be audible, it must vibrate at a specific frequency.
- The Range: The human ear can typically hear frequencies between 20 Hz and 20,000 Hz (20 kHz).
- Examples: Human speech, music, bird chirping, and the sound of a ringing phone.
- Fact: As we get older, our ability to hear very high-frequency sounds usually decreases.
What is Inaudible Sound?
Sounds that fall outside the range of 20 Hz to 20,000 Hz are known as inaudible sounds. Even though they are vibrating and carrying energy, our eardrums cannot pick them up.
Inaudible sounds are divided into two categories:
- Infrasonic Sounds: Sounds with frequencies below 20 Hz.
- Examples: Vibrations of the Earth’s crust (earthquakes), whales, and elephants communicating over long distances.
- Ultrasonic Sounds: Sounds with frequencies above 20,000 Hz.
- Examples: Bats use ultrasound for navigation (echolocation), and doctors use ultrasound for medical imaging.
Key Differences at a Glance
| Feature | Audible Sound | Inaudible Sound |
| Frequency Range | 20 Hz to 20,000 Hz | Below 20 Hz or Above 20,000 Hz |
| Human Detection | Can be heard by humans. | Cannot be heard by humans. |
| Categories | General sound/Music | Infrasonic and Ultrasonic |
| Examples | Piano, Talking, Thunder | Bat calls, Seismographic waves |
Why Can’t We Hear Everything?
Our ears are biological instruments with physical limits. The eardrum and the tiny bones in the middle ear are designed to vibrate efficiently only within the 20 Hz – 20,000 Hz window. If a vibration is too slow (Infrasonic) or too fast (Ultrasonic), our auditory system simply doesn’t respond to it.
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#Difference Between Audible and Inaudible Sound Class 8