Some animals can hear even the …

Infrasonic sounds cannot be heard by human beings. Example a vibrating simple pendulum produces infrasonic sound. Earthquakes and some animals like whales, elephants and rhinoceroses produce infrasonic sounds. The sounds of frequencies higher than 20,000 hertz are known as ultrasonic sounds. Ultrasonic sounds cannot be heard by human beings.  We cannot hear the screams of a bat because its screams consist of ultrasonic sound having a frequency much higher than 20,000 hertz. Children under the age of five and some animals, such as dogs can hear up to 25 kHz (1 kHz = 1000 Hz). 

Earthquakes and some animals like whales, elephants and rhinoceroses produce infrasonic sounds. The sounds of frequencies higher than 20,000 hertz are known as ultrasonic sounds. Ultrasonic sounds cannot be heard by human beings.  We cannot hear the screams of a bat because its screams consist of ultrasonic sound having a frequency much higher than 20,000 hertz. Children under the age of five and some animals, such as dogs can hear up to 25 kHz (1 kHz = 1000 Hz). As people grow older their ears become less sensitive to higher frequencies.

The sound which we are able to hear is called audible sound. The audible range of sound frequencies for human ear is from 20 Hz to 20,000 Hz. The sound of frequencies lower than 20 hertz are known as infrasonic sounds. Infrasonic sounds cannot be heard by human beings. Example a vibrating simple pendulum produces infrasonic sound. Earthquakes and some animals like whales, elephants and rhinoceroses produce infrasonic sounds. The sounds of frequencies higher than 20,000 hertz are known as ultrasonic sounds. Ultrasonic sounds cannot be heard by human beings.  We cannot hear the screams of a bat because its screams consist of ultrasonic sound having a frequency much higher than 20,000 hertz. Children under the age of five and some animals, such as dogs can hear up to 25 kHz (1 kHz = 1000 Hz). As people grow older their ears become less sensitive to higher frequencies.