Because if its too low or too high, our ears arn't sensetive enough to hear the sound. Ultrasound is called "ultra" sound because it is beyond the normal range of human hearing in the same way that ultraviolet light is beyond violet light and outside the normal range of human vision. While ultrasound has frequencies above the range of human hearing, infrasound has frequencies below the range of human hearing, in this case just as infrared light has frequencies below those of red light, and therefore outside the normal range of human vision.
Because their hearing apparatus (ear) is not tuned to hear ultrasound.
Sound waves too high for humans to hear are called: ultrasonic
"Sound" is a mechanical wave traveling through a medium. Ultrasound is sound, but its frequency is higher than humans can hear.
bat
Humans can't hear sounds that are below 20Hz (infrasound) or above 20,000Hz (ultrasound). Infrasound is produced by natural phenomena like earthquakes and by some animals, while ultrasound is used in medical imaging and by animals like bats for echolocation.
Sounds that are too high-pitched for the human ear to detect are often in the ultrasonic range, exceeding 20,000 Hz. While humans cannot hear these frequencies, some animals like certain bats and dolphins have the ability to hear and use them for communication or echolocation. Devices like ultrasonic pest repellents also utilize these frequencies to deter pests without affecting humans.
Yes
Ultrasound.
Sonic infrasound is a sound too low for humans to hear, below 20 Hertz. Ultrasound is a sound too high for humans to hear, above 20,000 Hertz.
No, while a dog can hear ultrasound frequencies up to about 45KHz (normal human hearing is only up to about 20KHz) the frequencies made by ultrasound imaging machines are usually in the MHz range, far beyond a dog's hearing range.
Yes they can
Humans may use sounds they cannot hear for various reasons such as communication with animals or in technological applications like ultrasound testing. These sounds are either outside the range of human hearing or used for specific purposes where their direct perception is not necessary.