What is a Christmas holiday without the traditional multicoloured lighting decorations? These Christmas lights just have a way of putting us into the mood of the season when they are adorned on houses, trees and streets. They come in different shapes and sizes.
The science behind Christmas lights
Christmas lights are engineered based on a phenomenon called Electroluminescence. This is a process in which electric current is passed through a material making it illuminate. The material used for the process can emit light when electric current flows through it. An example is the kind used in the regular Christmas lights which is a thin wire coated with phosphor.
Electrical devices such as LED lights and LCD screens also work with the Electroluminescence principle. The electricity used by Christmas lights is quite low thereby making them energy efficient. They are also able to be left working for a long time due to the very thin wire used which allows them to generate very low heat.
The various colours of light produced are attributed to the different phosphors used for the coating of the thin wires. This is because light is emitted by different individual phosphors at different wavelengths which are expressed in varying colors. Therefore, to achieve different colours of choice, appropriate phosphor combinations are employed.
History of Christmas lights
Before the Christmas lights we’re familiar with were invented, people used candles to light up their trees and homes with the aid of pins or wax. This was risky, due to the open fire that could destroy properties.
In 1880, Thomas Edison successfully invented the first strands of light which he hung outside of his laboratory, Menlo Park laboratory, that year to celebrate the Christmas season. Back then, Christmas lights were not available in preassembled forms, therefore engineers were required for the installation of these light strands on Christmas trees, making them to be used mostly by the rich.
After the invention, Edward H. Johnson assembled the first string of electric Christmas tree lights consisting of red, white and blue lights which he spun around his Christmas tree. In 1895, President Grover Cleveland lighted up the White House with the Christmas lights and this helped clear the uncertainties people had with the product. President Calvin Coolidge also decorated the national Christmas tree using 3,000 electric lights on the Christmas Eve of 1923.
Compared to the recently improved Christmas lights, the ones that were made earlier in the 1970s were larger, broke easily and were hot to handle due to the huge consumption of energy. They were not environmentally friendly. These disadvantages prompted the work on Light Emitting Diodes (LED) bulbs which require little energy with higher efficiency.
LED bulbs work by passing electric current through a microchip which in turn lights up the tiny light sources in the bulb called LED. LED lights were first invented by Nick Holonyak Junior in the 1960s, after which other engineers worked on their advancement thereby improving their efficiency and brightness which gives rise to our Christmas LED lights of today.
Different types of holiday lighting
- Incandescent light bulbs: The most popular and commonly used holiday lighting. They emit a broad-spectrum white light.
- LEDs (Light Emitting Diodes): There are two types which include coloured LEDs and white LEDs.
- Glow discharge lights: These are neon, mercury and argon fluorescent lamps. They also emit different colours depending on the chemical composition of the phosphor used. Colours include orange, purple, blue, green and yellow.
- Fibre optic lights: This type of Christmas holiday lighting is usually placed on a Christmas tree. Optics fibre extends from LED or incandescent lamps placed at the base of the tree to the tip of the tree branches.
- Laser projectors: Laser projectors are usually installed on a stake in front of a house during the holiday season. They emit lights resembling coloured dots like stars.
- Bubble lights: This is a kind of incandescent holiday light which consists of a coloured bubbling liquid inside of a sealed glass tube. It works due to the heat from the incandescent light. The bubbling liquid is methylene chloride which has a sustained bubbling effect.
- Light sculptures: These include lights that are mounted on frames such as metals or plastics to form a lighted sculpture of the frame