Sodium lamps are a type of lighting commonly used in streetlights and other outdoor applications. The word "sodium" is spelled /ˈsoʊdiəm/, with the stress on the first syllable. The "o" in the second syllable is pronounced like the "u" in "run." The plural of "lamp" is spelled with an "s" at the end, making the complete spelling of "sodium lamps" /ˈsoʊdiəm læmps/. These lamps are known for their distinctive yellow-orange glow, and are often used in areas where high visibility at night is important.
Sodium lamps, also known as sodium vapor lamps, are a type of electric lamp that emits light by passing an electrical current through ionized sodium vapor. They fall under the category of high-intensity discharge (HID) lamps and are commonly used in various lighting applications.
The primary component of sodium lamps is a sealed glass bulb containing a small amount of metallic sodium and a noble gas, typically argon. When an electric current is applied to the bulb, it excites the sodium atoms, causing them to emit a bright yellow-orange light. The color of this light, often referred to as "sodium orange," is monochromatic, meaning it is primarily composed of a single wavelength.
Sodium lamps are known for their high energy efficiency, making them particularly suitable for outdoor lighting purposes. They are widely used in street lighting, parking lots, warehouses, and industrial areas due to their ability to provide ample illumination over large areas. The distinctive yellow-orange color emitted by sodium lamps also enhances visibility in foggy or hazy conditions.
However, sodium lamps have limited color rendering capabilities, meaning they do not accurately reproduce the colors of illuminated objects. This deficiency makes them less suitable for applications where color perception is crucial, such as in retail displays or art galleries.
In recent years, LED technology has become an increasingly popular alternative to sodium lamps due to its higher efficiency and better color rendering abilities, although sodium lamps still remain in use in certain contexts.
The word "sodium" in "sodium lamps" refers to the element sodium (Na) which is used in the lamps. The etymology of the word "sodium" can be traced back to Latin. It comes from the Medieval Latin term "natrium", which was derived from the Arabic word "suda", meaning "headache". This is because sodium carbonate, a compound containing sodium, was historically used as a headache remedy. The English word "sodium" was later adopted from the Latin term.