What does the color blue light do?

Blue (blue) is a color. It is one of the three primary colors of red, green and blue light. Among these three primary colors, its wavelength is the shortest, 450~500nm, which is a short wavelength.

Due to the Rayleigh scattering of sunlight by dust in the air, the sky on a clear day is blue. Large amounts of water concentrated together appear blue due to the absorption of light at about 750 nanometers by the hydrogen-oxygen bonds in water molecules. Interestingly, heavy water is colorless because the deuterium-oxygen bond absorbs light with a relatively long wavelength (about 950 nanometers)

Blue is a symbol of eternity and is the coldest color. Blue is often associated with the ocean, sky, water, and the universe. Pure blue shows a kind of beauty, calmness, reason, tranquility and vastness. Due to the calm characteristics of blue, it has a rational and accurate image. In commercial design, most products or corporate images that emphasize technology and efficiency use blue as the standard color and corporate color, such as computers, cars, photocopiers, and photographic equipment. Wait, in addition, blue also represents melancholy, which is influenced by Western culture. This image is also used in literary works or commercial designs with emotional appeals.

In many countries the police uniform is blue. Police and ambulance lights are generally blue. Because blue has the meaning of courage.

Many Air Force and Navy uniforms are blue. Generally, the air force is sky blue and the navy is dark blue.

Blue collar generally refers to workers engaged in manual labor in factories. The name comes from the blue overalls that workers generally wear when working. In contrast, white-collar workers generally refer to office workers, who generally wear white shirts.

In Islam, blue is a color of purity.

European aristocrats are often said to have "blue blood." Some believe the name comes from their pale skin.

In the West, blue is generally the color for boys, and pink is usually the color for girls. Boys' clothes, toys, strollers, etc. are often light blue. What’s interesting is that this custom only started after the First World War. Before that blue was the color for girls and pink was the color for boys. Therefore, gay men used to be called "blue" in the West.

Blue—stocking clubs, blue stocking clubs refer to private parties in the cultural circle at that time. Because the vast majority of people attending such gatherings were women, and women at that time were not yet able to enter university studies. The term "blue stockings" soon became specific to women and thus acquired discriminatory connotations.

In Britain, wedding customs require each bride’s dowry to be as follows:

“Something old, something new, something borrowed, something blue.”

(Some Something old, something new, something borrowed, something blue - i.e. loyal)

Blue hour is popular in the United States and the United Kingdom. It refers to the time after get off work. , that is, time to relax.

Blue also represents beauty, freshness, tranquility, melancholy, open-mindedness and calmness!