What Is Ultrasound The sound waves having frequency higher than 20,000 Hz is called ultrasonic waves or ultrasound. Human beings cannot hear ultrasound. Dogs, bats and dolphins can hear ultrasound. For example bats and dolphins can hear sound waves having frequencies of about 150,000 Hz. Bats and dolphins detect the presence of any obstacle by hearing the echo of the sound … [Read more...] about What Is Ultrasound And Its Applications