Roy G. Biv

(Image credit: Miss Cellania)

Roy G. Biv is a mnemonic used to remember the colors of the visible spectrum: red, orange, yellow, green, blue, indigo, and violet. Let's learn something about all the colors.


How the Danish protest pig got its stripe.

(Image credit: Axel Krampe)

In the 19th century, Denmark and Germany went to war over a slice of the southern Jutland Peninsula (today called Schleswig-Holstein). Denmark claimed the land in 1848, but 16 years later, Germany regained the territory and promptly barred any Danes who lived there from raising their country’s flag. So, crafty Danish farmers started raising pigs. Through crossbreeding, they created a pig that resembled the Danish flag, featuring red fur and a prominent white belt. By the 20th century, the Protestschwein, or “protest pigs,” had become a snorting symbol of Danish cultural independence.


The fruit! Medieval English speakers rarely encountered the color orange in nature- so they simply called the shade geoluhread (yellow-red). The fruit, imported from northern India to Europe in the 11th century, changed that. Called orenge by medieval Latin speakers, the fruit took over geoluhread’s place in English in the 1530s.


The earliest usage of the word yellow in English appeared in Beowulf, to describe a shield carved from yew wood. Back then, it was spelled geolu or geolwe. More facts about yellow:

1. Gabriel García Márquez’s wife, Mercedes, placed a yellow rose on his writing desk every day for 55 years.

2. Tennis balls used to be black or white, but the International Tennis Federation changed them to yellow in 1972 to help TV viewers follow the match.

3. Wimbledon keeps its tennis balls at a temperature of exactly 68°F.

4. The founder of UPS wanted its trucks to be yellow. But a friend convinced him that brown would be easier  to clean.  

5. Stephen Hawking discovered that blond soccer players are 15 percent more likely to score on a penalty shootout. “This will remain one of science’s great mysteries,” he said.


The village of Woolpit, England, has always been sleepy. But in the 12th century, the parish -named for a group of pits dug to trap wolves- was consumed in mystery when a boy and girl were rescued from the trenches outside of town. The kids spoke an unknown tongue, wore strange clothing nobody could describe, and ate only raw beans. Oh, and their skin was green. Sir Richard de Calne took in the kids and tried nursing them back to health, but the boy eventually died of illness. The girl survived, and once she learned English, she told villagers a strange tale: She had been born in an underground place called St. Martin’s Land, where everything was green and it was always twilight. According to her story, she and her siblings had been herding cattle and followed the cows into a cave. They became disoriented and were led out by mysterious bells, only to emerge in Woolpit. (Image credit: Rod Bacon)

Nobody knows the real story. The kids may have been Flemish-speaking orphans from the nearby village of Fornham St. Martin. Their grassy complexion may have been from arsenic poisoning or an iron deficiency called chlorosis. Or maybe it’s just a tall tale. It doesn’t help that one of the historians who recorded the story was William of Newburgh- the same guy who convinced Europeans that the continent was crawling with vampires.


(Image credit: Flickr user Eric Wilcox)

In March of 2016, a nanotechnology startup created the world’s “blackest black” using light-absorbing carbon nanotubes. It wasn’t the first superlative shade. In 1960, minimalist artist Yves Klein created the world’s “bluest blue” -International Klein Blue. He unveiled it by displaying paint-soaked sponges and hiring nude women covered in paint to sprawl on canvases.


(Image credit: Flickr user Stéphane DAMOUR)

On the island of Java, the Kawah Ijen volcano spits out Technicolor lava that would give your Day-Glo crayons an inferiority complex.

1. Don’t be fooled! The lava isn’t actually indigo. The colorful flames erupt as sulfuric gases combust, emerging from the earth at temperatures up to 1,120°F.

2. Marvel at the flames, but don’t point at them. Javanese tradition says that pointing at a cloud of fire invites it to come toward you.

3. Liquid sulfur flows down Kawah Ijen into one of the world’s largest acid lakes, which boasts a pH of 0.5 -more corrosive than  battery acid.

4. Ceramic pipes installed over vents allow locals to mine the sulfur. The gas streams down the mountain, condenses into liquid, and congeals into yellow chunks used to make insecticide and batteries.

5. Photographing Kawah Ijen is a bad idea. When Olivier Grunewald tried in 2010, he lost one camera, and two lenses corroded because of the acid. “The feeling is like being on another planet,” he told


(Image credit: Lionel Allorge)

The time mauve was the new black.

Fashion really used to stink. Before the 19th century, fabric dyes were derived from plants and insects and often made clothes smell bad. Worse still, they were expensive and prone to fading. And purple was the worst of the bunch: To dye a single yard of fabric, you had to crush thousands of sea snails. That changed in 1856 when William Henry Perkin, an 18-year-old student at the Royal College of Chemistry in London, was issued a challenge by one of his professors.The goal? Make synthetic quinine, the malaria drug derived from the bark of the cinchona tree. Perkin saw promise in coal tar, a gloopy, toxic by-product of the Industrial Revolution. After one failed tar experiment involving ethanol extraction, Perkin noticed his rags were stained a “strangely beautiful” purple. He named it mauve, for the French mallow flower, and quit school to start a dye factory. Queen Victoria liked the shade, and by 1859, everybody was wearing purple. Punch magazine declared London had come down with the “mauve measles,” while All the Year Round magazine wrote, “We shall soon have purple buses and purple houses.” Thankfully, rival chemists used Perkin’s technique to develop other synthetic dyes, and by 1906 there were more than 2,000 hues available. Color us happy!

The article above appeared in the Scatterbrain section of the September-October 2016 issue of mental_floss magazine. It is reprinted here with permission.

Don't forget to feed your brain by visiting Mental Floss' extremely entertaining website and blog today!

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