Speed of sound
for humans the audible frequency limits are normally somewhere between 20 Hz and 20,000 Hz (or 20 kHz). Since we are all different this number is not definite, also we damage our hearing through our lifetime which means that the upper limit decrease as we get older.
Basically sound is a form of energy that travels through air, water and other matter in different waves. The matter that supports the sound is called a “Medium” and therefore, sound cannot travel through vacuum1. The ear collects sound with the outer part of the ear all the folds are there to direct the sound into the ear canal. In the inner ear, the sound meets the temporal bone which is the densest bone of the body. Also, the hollow channels are filled with liquid and really sensory epithelium2. This epithelium is studded with hair cells and when they get stimulated the brain perceives the vibrations.
Often we say that it is the ears that are hearing but we actually hear with our brains. Therefore damages on your ears can make you deaf but also brain damages can cause it.
Humans are also different from animals. I.e. a dog can hear vibrations higher than 20 kHz3.
The speed is depending on what the medium the sound is traveling through. In water it travels faster because there are more medium to carry the sound. In air (gases) the speed is also depended on the temperature. At 20 C° the speed of sound is 343 m/s (which is 1,230 km/h or 767 mph) so if this sound produces an echo within 2 seconds, the object (i.e. a wall) will have to be half that distance away. The distance for an object with a 2-second echo return would be 1 second times 343.
for humans the audible frequency limits are normally somewhere between 20 Hz and 20,000 Hz (or 20 kHz). Since we are all different this number is not definite, also we damage our hearing through our lifetime which means that the upper limit decrease as we get older.
Basically sound is a form of energy that travels through air, water and other matter in different waves. The matter that supports the sound is called a “Medium” and therefore, sound cannot travel through vacuum1. The ear collects sound with the outer part of the ear all the folds are there to direct the sound into the ear canal. In the inner ear, the sound meets the temporal bone which is the densest bone of the body. Also, the hollow channels are filled with liquid and really sensory epithelium2. This epithelium is studded with hair cells and when they get stimulated the brain perceives the vibrations.
Often we say that it is the ears that are hearing but we actually hear with our brains. Therefore damages on your ears can make you deaf but also brain damages can cause it.
Humans are also different from animals. I.e. a dog can hear vibrations higher than 20 kHz3.
The speed is depending on what the medium the sound is traveling through. In water it travels faster because there are more medium to carry the sound. In air (gases) the speed is also depended on the temperature. At 20 C° the speed of sound is 343 m/s (which is 1,230 km/h or 767 mph) so if this sound produces an echo within 2 seconds, the object (i.e. a wall) will have to be half that distance away. The distance for an object with a 2-second echo return would be 1 second times 343.
1) Vacuum comes from the Latin word “Vacuus” and basically means “empty”. A vacuum is a space that has no matter. If there is no matter, the sound has no medium to travel through.
2) Epithelium is the tissue that covers the whole surface of our body and it contains really compacted cells that are ranged in one or more layers.
3) KHz means kilohertz and is used to measure radio frequency radiation and is equal to 1000 hertz. You will always use MHz (Megahertz) and GHz (Gigahertz).
