Anightlight is a smalllight fixture, usually electrical, placed for comfort or convenience in dark areas or areas that may become dark at certain times, such as at night orduring an emergency. Small long-burningcandles serving a similar function are referred to as "tealights".
People usually use nightlights for the sense of security which having a light on provides, or to relievefear of the dark, especially in young children. Nightlights are also useful to the general public by revealing the general layout of a room without requiring a major light to be switched on, for avoiding tripping over stairs, obstacles, or pets, or to mark anemergency exit. Exit signs often usetritium radioluminescence. Homeowners usually place nightlights in bathrooms, kitchens and hallways to avoid turning on the main light fixture, especially late at night, and causing their eyes to adjust to the brighter light.[1]
Some frequent travelers carry small nightlights for temporary installation in their guestroom and bathroom, to avoid tripping or falls in an unfamiliar nighttime environment.Gerontologists have recommended use of nightlights to help prevent falls, which can often be life-threatening to the elderly.[2]
The low cost of nightlights has enabled a proliferation of different decorative designs, some featuringsuperheroes and fantastical designs, while others feature the basic simplicity of a small luminous disc.
The 1990 song "Birdhouse in Your Soul" byThey Might Be Giants is a song sung from the perspective of a nightlight.[3]
Early electrical nightlights used smallincandescent lamps or smallneon lamps to provide light, and were much safer than small candles using an open flame. The neon versions consumed very little energy and had a long life, but had a tendency to flicker on and off (reminiscent of a candle), which some users liked and others found annoying. In the 1960s, small nightlights appeared that featured a low-powerelectroluminescent panel emitting soft green or blue light; similar lights are still available today.[4]
Some nightlights include aphotocell, which enables them to switch off when the ambient light is sufficiently bright. Other designs also feature a built-inpassive infrared sensor to detect motion, and only switch on when somebody is passing by in the dark. With the availability of low-costLEDs, many different variants have become available, featuring different colours, sometimes changing automatically or in a user-controllable way.
TheUS Consumer Product Safety Commission, or UCPSC, reports it receives about 10 reports per year where nightlights close to flammable materials were cited as responsible for fires; they recommend the use of nightlights withLED bulbs cooler than the four or seven watt incandescent light bulbs still used in some older products.[5]
AUniversity of Pennsylvania study indicated that sleeping with the light on or with a nightlight was associated with a greater incidence ofnearsightedness in children.[6] However, a later study atOhio State University contradicted the earlier conclusion.[7] Both studies were published in the journalNature.
Another study has indicated that sleeping with the light on may protect the eyes of diabetics fromretinopathy, a condition that can lead to blindness.[8] However, the initial study is still inconclusive.
The optimal sleeping light condition is said by some to be total darkness.[9] If a nightlight is used within a sleeping area, it is recommended to choose a dim reddish or amber light to minimize disruptive effects on sleep cycles.[10][1] In addition, nightlights may be useful in locations other than sleeping areas, such as hallways, bathrooms, or kitchens, to allow late night trips to be made without turning on the full light, while preserving a dark sleeping environment.[2]
The dictionary definition ofnightlight at Wiktionary