White noise, according to HowStuffWorks.com, is a combination of all different frequencies of sound being emitted at the same time. It is called white noise because it works similarly to white light. As white light contains all the different colors in the spectrum, so does white noise contain all of the different sound frequencies.
How it Works
It is effective at blocking out other noise because your brain cannot distinguish that many different frequencies. It will not be distracted by other noise, simply because it cannot separate it from the hum of all the frequencies together that is created in white noise. So, if you are trying to sleep in a place where there is a lot of commotion, other conversation, or traffic noise; white noise may be what you need to get a restful night sleep. If you are already sleeping somewhere quiet, white noise may not make any difference in the quality of your sleep.
There are also variations of white noise. One example is pink noise. Pink noise is filtered from white noise. WiseGeek discusses that pink noise is based on octaves and emphasizes lower tones. Because of these qualities it is more effective at blocking out lower noises such as rumbling trucks.
Pure white noise will sound like static and recordings can be purchased to assist with sleep. Other sounds have a similar effect to white noise, such as a fan or vacuum. Some people may find sounds such as rainfall, ocean or nature noises, like crickets, helpful for relaxation and falling asleep, however, they do not necessarily block out noise in the same manner as white noise.
If you have had trouble sleeping because your neighbor’s dog has been barking or a loud truck has been roaring up and down your street, try using white noise to block out the disturbance. You may get a better night’s sleep and improve neighborhood relations!