CLOSE
iStock
iStock

Why Does the Airplane Oxygen Mask Have a Bag That “May Not Inflate”?

iStock
iStock

If you’ve seen the airplane safety demonstration enough times, you know the drill for the oxygen masks. If there is a loss in cabin pressure the masks come down. First, you put yours over your face and pull the strap over your head, and then you help anyone else who needs it. Makes sense. You’re no good to others if you’ve passed out from lack of oxygen. But what about the next part, when they tell you that “although the bag on the oxygen mask may not inflate, oxygen is flowing to the mask”? If the bag doesn’t do anything important, why is it there?

The passenger airplane masks are “continuous flow” masks, which are different from “diluter demand” masks, which are what the crew have. A diluter demand mask only releases oxygen when the user inhales. This prevents waste of oxygen and allows the instruments on the mask to determine the exact oxygen level being delivered. It functions to make sure the crew stays alert enough to get the aircraft down into more oxygenated air.

A continuous flow mask is constantly releasing oxygen whether the user is inhaling or not. Passenger masks don’t have to function as efficiently because they’re there just to make sure you stay alive. Even with some waste, there's enough oxygen to sustain everyone until the airplane reaches denser air.

The bag on the mask allows for a bit of oxygen savings. If the mask is situated well on your face, the oxygen continuously coming out will collect in the bag as you are exhaling instead of seeping out the sides of the mask. (The air-flow on any oxygen mask is one-way. Exhaled breath does not travel back into the tube, but out of valves on the mask.) However, even if there is a good seal, if you are breathing fast (which is probably what’s going to happen in a panicky situation), you’ll probably suck down what’s going through the bag before it fills. They don't want people thinking, "Hey this thing's not doing anything!" and taking off the mask or freaking out if their neighbor's bag inflates but theirs doesn't. That’s why the safety demonstration wants to reassure you that, yes, your mask is still doing its job even if the bag isn’t inflating. You’ve got enough to worry about if the oxygen masks are down. Your oxygen mask bag shouldn’t be one of them.

nextArticle.image_alt|e
iStock
arrow
Big Questions
Why Do Fruitcakes Last So Long?
iStock
iStock

Fruitcake is a shelf-stable food unlike any other. One Ohio family has kept the same fruitcake uneaten (except for periodic taste tests) since it was baked in 1878. In Antarctica, a century-old fruitcake discovered in artifacts left by explorer Robert Falcon Scott’s 1910 expedition remains “almost edible,” according to the researchers who found it. So what is it that makes fruitcake so freakishly hardy?

It comes down to the ingredients. Fruitcake is notoriously dense. Unlike almost any other cake, it’s packed chock-full of already-preserved foods, like dried and candied nuts and fruit. All those dry ingredients don’t give microorganisms enough moisture to reproduce, as Ben Chapman, a food safety specialist at North Carolina State University, explained in 2014. That keeps bacteria from developing on the cake.

Oh, and the booze helps. A good fruitcake involves plenty of alcohol to help it stay shelf-stable for years on end. Immediately after a fruitcake cools, most bakers will wrap it in a cheesecloth soaked in liquor and store it in an airtight container. This keeps mold and yeast from developing on the surface. It also keeps the cake deliciously moist.

In fact, fruitcakes aren’t just capable of surviving unspoiled for months on end; some people contend they’re better that way. Fruitcake fans swear by the aging process, letting their cakes sit for months or even years at a stretch. Like what happens to a wine with age, this allows the tannins in the fruit to mellow, according to the Wisconsin bakery Swiss Colony, which has been selling fruitcakes since the 1960s. As it ages, it becomes even more flavorful, bringing out complex notes that a young fruitcake (or wine) lacks.

If you want your fruitcake to age gracefully, you’ll have to give it a little more hooch every once in a while. If you’re keeping it on the counter in advance of a holiday feast a few weeks away, the King Arthur Flour Company recommends unwrapping it and brushing it with whatever alcohol you’ve chosen (brandy and rum are popular choices) every few days. This is called “feeding” the cake, and should happen every week or so.

The aging process is built into our traditions around fruitcakes. In Great Britain, one wedding tradition calls for the bride and groom to save the top tier of a three-tier fruitcake to eat until the christening of the couple’s first child—presumably at least a year later, if not more.

Though true fruitcake aficionados argue over exactly how long you should be marinating your fruitcake in the fridge, The Spruce says that “it's generally recommended that soaked fruitcake should be consumed within two years.” Which isn't to say that the cake couldn’t last longer, as our century-old Antarctic fruitcake proves. Honestly, it would probably taste OK if you let it sit in brandy for a few days.

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

nextArticle.image_alt|e
iStock
arrow
Big Questions
What's the Difference Between Stuffing and Dressing?
iStock
iStock

For carbohydrate consumers, nothing completes a Thanksgiving meal like stuffing—shovelfuls of bread, celery, mushrooms, and other ingredients that complement all of that turkey protein.

Some people don’t say “stuffing,” though. They say “dressing.” In these calamitous times, knowing how to properly refer to the giant glob of insulin-spiking bread seems necessary. So what's the difference?

Let’s dismiss one theory off the bat: Dressing and stuffing do not correlate with how the side dish is prepared. A turkey can be stuffed with dressing, and stuffing can be served in a casserole dish. Whether it’s ever seen the inside of a bird is irrelevant, and anyone who tells you otherwise is wrong and should be met with suspicion, if not outright derision.

The terms are actually separated due to regional dialects. “Dressing” seems to be the favored descriptor for southern states like Mississippi, Tennessee, South Carolina, and Georgia, while “stuffing” is preferred by Maine, New York, and other northern areas. (Some parts of Pennsylvania call it "filling," which is a bit too on the nose, but to each their own.)

If “stuffing” stemmed from the common practice of filling a turkey with carbs, why the division? According to The Huffington Post, it may have been because Southerners considered the word “stuffing” impolite, so never embraced it.

While you should experience no material difference in asking for stuffing or dressing, when visiting relatives it might be helpful to keep to their regionally-preferred word to avoid confusion. Enjoy stuffing yourselves.

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

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios