ASK THE EXPERTS

Still more questions about the world we live in, with answers from the world’s top trivia experts.

WHITE WASH

Q: Why is toilet paper white?

A: “One of the primary reasons toilet paper is white is the same reason most toilets are: white toilet paper looks cleaner than the natural brownish color the paper is before it’s bleached. If toilet paper was the original brown hue, on a purely aesthetic level, would you use it? Or, perhaps more aptly, would you prefer it over the white variety? The consensus among toilet paper makers, like Kimberly-Clark, who rang in on this issue, is that people consistently choose the white. One can only assume they’ve done extensive marketing studies to back that notion up, but even without access to those studies, it makes intuitive sense.

“That said, there are other factors at play. For starters, white isn’t just an aesthetic choice, the white color of toilet paper is usually achieved by bleaching the paper, and this can make the paper much softer. The bleaching process removes lignin, a polymer in wood that makes the tree more rigid. Besides the added softness, removing lignin adds a shelf-life to the paper. If you’ve ever seen an old newspaper, you may notice that the paper starts to yellow as it ages; this yellowing is due to the presence of lignin in the newspaper. Obviously toilet paper that yellows over time, especially unevenly, isn’t going to fly off the shelves.

“So that’s partially why many toilet paper manufacturers bleach the toilet paper in the first place, but why don’t they still color it in many countries? The primary reason here probably has more to do with the extra cost. To make up for this, they’d need to charge a little more for the dyed version. If this would have the potential to increase sales, they’d no doubt start making colored toilet paper tomorrow.” (From “Why Is Toilet Paper Always White?” by Karl Smallwood for TodayIFoundOut.com)

TELL ME MORE ABOUT MY EYES

Q: Why do blue eyes seem to be so much bluer than other eyes seem to be the color they are?

A: “Brown eyes get their color from melanin, the same pigment that colors your skin. But blue eyes don’t have any blue pigment in them. Blue eyes get their color the same way water and the sky get their blue color. They scatter light so that more blue light reflects back out.

“The colored part of the eye is called the iris. It’s a structure that contains muscle and other kinds of cells. You can see the iris in action when it squeezes or relaxes to let in more or less light through the pupil. The iris is made up of two layers. For almost everyone—even people with blue eyes—the back layer (called the pigment epithelium) has brown pigment in it.

Worse than you think: When mosquitos drink your blood, they also pee on you.

“The front layer of the iris (called the stroma) is made up of overlapping fibers and cells. For people with brown eyes, some of the cells also have brown pigment in them. If there is no pigment at all in this front layer, the fibers scatter and absorb some of the longer wavelengths of light that come in. More blue light gets back out and the eyes appear to be blue.” (From “Your Blue Eyes Aren’t Really Blue,” by Dan T. Gudgel, American Academy of Ophthalmology)

TOILET-TRON 2000

Q: Why do so many scientific words end in “tron”?

A: “If you grew up in the 1980s, chances are you’ll remember riding the Gravitron at the local fair, or struggling to get past level one of the video game Robotron. That would be after you got up early to watch Voltron on the eponymous TV series, and rushed out to see Disney’s 1982 film Tron.

“The suffix -tron, along with -matic and -stat, are what Stanford University historian Robert Proctor calls ‘embodied symbols.’ Like the heraldic shields of ancient knights, these morphemes were painted onto the names of scientific technologies to proclaim one’s history and achievements to friends and enemies alike. Stat signaled something measurable, while matic advertised free labor; but tron, above all, indicated control. The suffix emblazoned the banners of nuclear physics’ Cosmotron, modern biology’s Climatron, and early AI’s perceptron—displaying to all our mastery over matter, life, and information. By the turn of the millennium, though, most of that was gone. True, Sony’s jumbotron still helps to broadcast presidential addresses and rock concerts, but today it’s all too easy to forget the technological promise that tron contains, and hear only its kitschy and cartoonish overtones.

“In contemporary usage the term springs from ancient Greek, with the invention of the first vacuum tube or ‘kenotron’ around 1904; its creator came up with the name by combining the Greek words for ‘empty’ (keno) and ‘tool’ (tron). Subsequently, the radiotron, thyratron, klystron, and rhumbatron went on to become vital components of the radio industry in the 1930s, while the resonant cavity magnetron was at the heart of every radar set in the Second World War. Don’t be deceived, though: These components bear scant relationship to elementary particles such as the electron, neutron, and positron, all of which really end in the suffix -on.” (From “A Tale of ‘Trons’: The Suffix That Tells the Story of Modern Science” by David Munns for Aeon magazine)

In India, Spider-Man’s alter ego Peter Parker is known as Pavitr Prabhakar.