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Why Do We Feel Hot in Temperatures Lower Than Our Body Temp?

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Reader PartiallyDeflected wrote in to ask, “Since our body temperature is around 98 degrees, why do we feel hot when it’s 90?”

Pretty much everything your body does, whether physical (like muscle contractions) or chemical (like some stages of digestion), produces heat as a byproduct. You’re constantly generating it, and constantly losing it to the environment. The hypothalamus, an almond-sized chunk of the brain that rests deep within its squishy confines, acts as the body’s thermostat and tries to keep the amount of heat created and the amount lost close to each other and maintain normal body temperature.

Normally, this is easy enough. Heat seeks equilibrium, a state where everything is the same temperature as everything around it. It’s why a bowl of hot soup and a glass of ice water will both reach room temperature if you leave them out on the counter long enough. Usually, the environment around you is cooler than your body, so your little thermostat can just dump the excess heat into it with thermoregulatory processes like sweating (where the heat is lost by evaporation) and increasing bloodflow through capillaries close to the surface of the skin (where the heat is lost through radiation, convection and conduction).

When there’s a big temperature difference between your body and your environment, heat flows out of you and into the air pretty easily, and you cool down quickly. When the environment is warmer and closer to our body temperature, though, the heat doesn’t transfer as readily or quickly via radiation, convection, and conduction. You’re stuck hanging on to some of your excess heat for longer, and you feel hot and uncomfortable (and if the ambient temperature goes higher than your body temp, heat’s quest for equilibrium means that you’ll take on excess heat from the environment). If conditions are hot and dry, the body can deal with these situations by ramping up sweat to get rid of more heat through evaporation. When it’s hot and humid, though, you really feel hot and gross because the high moisture content of the air makes it more difficult for the sweat to evaporate.

If you spend enough time in a situation where the heat you generate or absorb from the environment exceeds the heat you’re getting rid of, your core temperature will rise and you can suffer from heat illnesses.

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Big Questions
What is Duck Sauce?
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A plate of Chinese takeout with egg rolls and duck sauce
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We know that our favorite Chinese takeout is not really authentically Chinese, but more of an Americanized series of menu options very loosely derived from overseas inspiration. (Chinese citizens probably wouldn’t recognize chop suey or orange-glazed chicken, and fortune cookies are of Japanese origin.) It would also be unusual for "real" Chinese meals to be accompanied by a generous amount of sauce packets.

Here in the U.S., these condiments are a staple of Chinese takeout. But one in particular—“duck sauce”—doesn’t really offer a lot of information about itself. What exactly is it that we’re pouring over our egg rolls?

Smithsonian.com conducted a sauce-related investigation and made an interesting discovery, particularly if you’re not prone to sampling Chinese takeout when traveling cross-country. On the East Coast, duck sauce is similar to sweet-and-sour sauce, only fruitier; in New England, it’s brown, chunky, and served on tables; and on the West Coast, it’s almost unheard of.

While the name can describe different sauces, associating it with duck probably stems from the fact that the popular Chinese dish Peking duck is typically served with a soybean-based sauce. When dishes began to be imported to the States, the Americanization of the food involved creating a sweeter alternative using apricots that was dubbed duck sauce. (In New England, using applesauce and molasses was more common.)

But why isn’t it easily found on the West Coast? Many sauce companies are based in New York and were in operation after Chinese food had already gained a foothold in California. Attempts to expand didn’t go well, and so Chinese food aficionados will experience slightly different tastes depending on their geography. But regardless of where they are, or whether they're using the condiment as a dipping sauce for their egg rolls or a dressing for their duck, diners can rest assured that no ducks were harmed in the making of their duck sauce.

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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Big Questions
Can You Really Go Blind Staring at a Solar Eclipse?
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A total solar eclipse will cut a path of totality across the United States on August 21, and eclipse mania is gripping the country. Should the wide-eyed and unprotected hazard a peek at this rare phenomenon?

NASA doesn't advise it. The truth is, a quick glance at a solar eclipse won't leave you blind. But you're not doing your peepers any favors. As NASA explains, even when 99 percent of the sun's surface is covered, the 1 percent that sneaks out around the edges is enough to damage the rod and cone cells in your retinas. As this light and radiation flood into the eye, the retina becomes trapped in a sort of solar cooker that scorches its tissue. And because your retinas don't have any pain receptors, your eyes have no way of warning you to stop.

The good news for astronomy enthusiasts is that there are ways to safely view a solar eclipse. A pair of NASA-approved eclipse glasses will block the retina-frying rays, but sunglasses or any other kind of smoked lenses cannot. (The editors at MrEclipse.com, an eclipse watchers' fan site, put shades in the "eye suicide" category.) NASA also suggests watching the eclipse indirectly through a pinhole projector, or through binoculars or a telescope fitted with special solar filters.

While it's safe to take a quick, unfiltered peek at the sun in the brief totality of a total solar eclipse, doing so during the partial phases—when the Moon is not completely covering the Sun—is much riskier.

WOULDN'T IT BE EASIER TO JUST TELL YOUR KIDS THEY WILL GO BLIND?

NASA's website tackled this question. Their short answer: that could ruin their lives.

"A student who heeds warnings from teachers and other authorities not to view the eclipse because of the danger to vision, and learns later that other students did see it safely, may feel cheated out of the experience. Having now learned that the authority figure was wrong on one occasion, how is this student going to react when other health-related advice about drugs, alcohol, AIDS, or smoking is given[?]"

This story was originally published in 2012.

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