Science Common Sense
1342 - Why can't human ears hear ultrasonic sounds
Human ears can't hear ultrasonic sounds because they are too high. You see, when sound waves reach our ears, they make our eardrum vibrate. Those vibrations then send signals to our brain, which helps us hear the sounds.
Ultrasonic sounds have really, really fast vibrations that are higher than 20,000 times per second. That's too fast for our eardrums to catch, so those vibrations don't send signals to our brain. As a result, we can't hear those sounds.
Think of it like trying to dance to a beat that's too fast. You can't keep up, right? Same thing with our ears and ultrasonic sounds.