Table of Contents
- Audible Sounds
- Infrasonic Sounds
- Ultrasonic Sounds
- Applications of Ultrasound: Sonar
- What’s Next?
In the last segment, we learnt about multiple reflections and reverberation. In this segment, we are going to learn about ultrasound and its applications.
The sounds can be classified into different categories based on their frequencies.
The frequency range of sounds that human beings can hear extends from 20 Hz to 20,000 Hz. However, this range varies as we age. For example, kids can hear sound up to frequencies 20,000 Hz. As humans grow old, ears become less sensitive to higher frequency sounds.
The sounds having a frequency below 20 Hz are called infrasonic sounds.
Some animals like rhinoceroses, whales and elephants produce sound in the infrasound range. In fact, rhinoceroses can communicate using infrasound frequencies less than 5 Hz.
The sounds having a frequency above 20,000 Hz are called ultrasonic sounds or
Ultrasound is produced by animals like dolphins and bats.
Applications of Ultrasound: Sonar
Sonar is a device installed in ships, submarines, etc. that is used in detecting underwater objects or measuring the depth of the sea. Sonar stands for sound navigation and ranging. It consists of a transmitter and a detector. The transmitter produces ultrasonic waves which transmit through the water and strike the object at the seabed. And then these ultrasonic waves get reflected from the seabed and are received by this detector.
The detector then converts these ultrasonic waves into electrical signals. These signals then tell us the details about the object present at seabed or the depth of the sea.