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Why Are Potato Chip Bags Always Half-Empty?

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As disappointing as it can be to tear into a bag of Lay’s to find empty air where your afternoon snack should be, that extra space in the package is there for a reason. “Slack fill” is an intentional choice by snack makers who want to protect their delicate products from the damage of rough handling during the shipping process. When products are stacked atop one another, crammed into tight spaces, or simply jostled around in the back of a delivery truck, slack fill serves as an air cushion that prevents potato chips from becoming potato crumbs. 

That’s not just any ordinary air puffing up potato chip bags, either: It’s nitrogen. Oxygen can cause the potatoes to spoil and the oil to go rancid, and the humidity found in ambient air makes the chips go soggy. Instead, packages are filled with nitrogen gas to help the snacks stay fresh, which a trained panel of tasters confirmed in a 1994 food science study. Nitrogen flushing isn’t harmful in any way, since about 78 percent of the air we breathe is composed of nitrogen already. However, that doesn’t excuse the sheer proportion of space that gas occupies in a bag that’s supposed to be filled with food.

Although the federal Fair Packaging and Labeling Act passed in 1966 required manufacturers to clearly indicate the net weight of their product’s contents to prevent customers from being duped by huge-seeming containers on the shelves (new and improved potato chips, now with 50 percent more air!), the regulations are rarely enforced. Humans are terrible at accurately perceiving size, and even the most discerning shoppers will automatically assume that larger packaging means more product if they don’t look too closely at the label. So while some extra space in a bag can help keep potato chips fresh and intact, any more than necessary might be the company trying to pull a fast one over us.

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Big Questions
Where Did the Myth That Radiation Glows Green Come From?
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by C Stuart Hardwick

Probably from radium, which was widely used in self-luminous paint starting in 1908. When mixed with phosphorescent copper-doped zinc sulfide, radium emits a characteristic green glow:


Quora

The use of radioluminescent paint was mostly phased out by the mid-1960s. Today, in applications where it is warranted (like spacecraft instrument dials and certain types of sensors, for example), the radiation source is tritium (radioactive hydrogen) or an isotope of promethium, either of which has a vastly shorter half life than radium.

In most consumer products, though, radioluminescence has been replaced by photoluminescence, phosphors that emit light of one frequency after absorbing photons of a difference frequency. Glow-in-the-dark items that recharge to full brightness after brief exposure to sunlight or a fluorescent light only to dim again over a couple of hours are photoluminescent, and contain no radiation.

An aside on aging radium: By now, most radium paint manufactured early in the 20th century has lost most of its glow, but it’s still radioactive. The isotope of radium used has a half life of 1200 years, but the chemical phosphor that makes it glow has broken down from the constant radiation—so if you have luminescent antiques that barely glow, you might want to have them tested with a Geiger counter and take appropriate precautions. The radiation emitted is completely harmless as long as you don’t ingest or inhale the radium—in which case it becomes a serious cancer risk. So as the tell-tale glow continues to fade, how will you prevent your ancient watch dial or whatever from deteriorating and contaminating your great, great grandchildren’s home, or ending up in a landfill and in the local water supply?

Even without the phosphor, pure radium emits enough alpha particles to excite nitrogen in the air, causing it to glow. The color isn’t green, through, but a pale blue similar to that of an electric arc.


Quora

This glow (though not the color) entered the public consciousness through this early illustration of its appearance in Marie Curie’s lab, and became confused with the green glow of radium paints.

The myth is likely kept alive by the phenomenon of Cherenkov glow, which arises when a charged particle (such as an electron or proton) from submerged sources exceeds the local speed of light through the surrounding water.

So in reality, some radionuclides do glow (notably radium and actinium), but not as brightly or in the color people think. Plutonium doesn’t, no matter what Homer Simpson thinks, unless it’s Pu-238—which has such a short half life, it heats itself red hot.


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This post originally appeared on Quora. Click here to view.

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Big Questions
How Are Royal Babies Named?
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Jack Taylor, Getty Images

After much anticipation, England's royal family has finally received a tiny new addition. The birth of the Duke and Duchess of Cambridge's second son was confirmed by Kensington Palace on April 23, but the name of the royal newborn has yet to be announced. For the heir to the British throne and his wife, choosing a name for their third child—who is already fifth in line to the throne—likely won't be as easy as flipping through a baby name book; it's tradition for royals to select names that honor important figures from British history.

According to ABC WJLA, selecting three or four names is typical when naming a royal baby. Will and Kate followed this unwritten rule when naming their first child, George Alexander Louis, and their second, Charlotte Elizabeth Diana. Each name is an opportunity to pay homage to a different British royal who came before them. Some royal monikers have less savory connotations (Prince Harry's given name, Henry, is reminiscent of a certain wife-beheading monarch), but typically royal babies are named for people who held a significant and honorable spot in the family tree.

Because there's a limited pool of honorable monarchs from which to choose, placing bets on the royal baby name as the due date approaches has become a popular British pastime. One name that keeps cropping up this time around is James; the original King James ruled in the early 17th century, and it has been 330 years since a monarch named James wore the crown.

If the royal family does go with James for the first name of their youngest son, that still leaves at least a couple of slots to be filled. So far, the couple has stuck with three names each for their children, but there doesn't seem to be a limit; Edward VIII, who abdicated the throne to George VI in 1936, shouldered the full name of Edward Albert Christian George Andrew Patrick David.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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