When you are asleep and relaxed, and breathing through your mouth rather than through your nose, the air coming out causes your soft palate, the tissue at the back and top of your mouth, to flutter back and forth. This fluttering, or vibration, makes a sound called a snore. Often this vibration causes the cheeks, lips, and nostrils to vibrate as well, causing an even louder snore.
Although many ways have been tried to stop snoring from tying a bandage from the chin to the top of the head to keep the mouth closed, to actually removing part of the soft palate, no one has found a sure-fire method. However, some people claim that if you sleep on your side rather than on your back, you are less likely to snore. Nobody knows why, but men snore more than women and children.
The loudest snore recorded has been measured at 69 decibels, or almost as loud as a pneumatic drill!