May 16 – the International Day of Light
The International Day of Light promotes awareness of the roles light plays in our lives while also recognizing its various benefits and technological applications in science, culture, art, education, as well as in sustainable development, medicine, communications, energy industry, and elsewhere. Various local and global activities seek to demonstrate how science, technology, art and culture can help improve the society. The International Day of Light has been officially proclaimed by and is celebrated under the aegis of UNESCO.
Why May 16?
The International Day of Light is celebrated on May 16 each year. The date marks the anniversary of the first successful operation of the laser by the physicist and engineer Theodore Maiman in 1960. The day seeks to promote scientific collaboration and maximize its potential to promote peace and sustainable development.
Check out the official UNESCO video to find out more:
What sources of light are there?
Bodies and substances whose internal structure makes it possible for them to emit light (flame, bulb, the Sun)
Bodies and substances that reflect rather than emit light (clouds, lamp shades, reflector lamps)
These include astronomical bodies, chemical reactions, electric discharges, tectonic phenomena, and biological sources
Traditionally classified by a number of factors, artificial light sources are most commonly grouped by the source type and how light is produced. There are incandescent sources where the emission of light is a result of the body’s high temperature (e.g. light bulbs), cold light producing luminescent sources (e.g. LEDs), and gas-discharge lamps (e.g. low-pressure fluorescent lamps, high-pressure sodium lamps).
LED as a light source
LED stands for light-emitting diode. As opposed to a regular diode, an LED is specifically designed to produce visible, infrared or ultraviolet light. Thanks to a decrease in the price of LEDs and their significantly higher lumen output per watt, fluorescent tubes and incandescent light bulbs in homes, cars and industry are being phased out and substituted by LEDs. This trend has been around for years but became especially notable in 2020.
Did you know Nick Holonyak Jr. (born 1928) invented and demonstrated the first LED that emitted visible spectrum at the University of Illinois at Urbana-Champaign in 1962?
Sources: wikipedia.org, unesco.org