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13 Scientific Terms Even Smart People Misuse

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When scientists use these words, they typically mean something completely different than what they do when non-scientists use them. Sometimes our definitions are too narrow or too broad, and sometimes, we use terms interchangeably when they actually shouldn't be. We dug deep into the American Museum of Natural History's website to help set the record straight.

1. and 2. Poisonous and venomous

Though the words poison and venom are often used interchangeably—and although they both describe a toxin that interferes with a physiological process—there is a difference. It’s all about how the substance is delivered: Venom is delivered via an anatomical device like fangs, while poison is usually inhaled, ingested, or absorbed. As Mark Siddall, Curator of Invertebrate Zoology at AMNH, explains in the clip above, both the rough-skinned newt and the blue-ringed octopus produce a powerful toxin called tetrodotoxin. But scientists call the octopus venomous because it delivers the substance through a bite, and consider the newt poisonous because the toxin is in its skin.

3. Microbes

When most people hear the word “microbe,” they think of stuff that they can't see that's going to make them sick. But while some do cause disease, not all microbes, or microscopic organisms, are bad; in fact, some are essential for life. Microbes include bacteria, viruses, fungi, and protozoa, and make up most of the life on our planet. For every human cell in our bodies, there are about 10 resident microbes; only a small percentage are pathogens.

4., 5., and 6. Meteor, meteorite, and asteroid

Although some use these terms interchangeably, meteors, meteorites, and asteroids are all different things. Here’s how to use them correctly: Asteroids are the rocky bodies that orbit the Sun mostly between Mars and Jupiter; they’re much smaller than planets, and they're sometimes pulled out of their orbit by the force of Jupiter’s gravity and travel toward the inner solar system. The vast majority of meteorites—rocks that fall to Earth from space and actually reach the Earth's surface—are parts of asteroids. Like meteorites, meteors are objects that enter Earth’s atmosphere from space—but they’re typically grain-sized pieces of comet dust that burn up before reaching the ground, leaving behind trails that we call “shooting stars” as they vaporize.

7. Theory

When most people use the word theory, they're talking about a hunch or guess. But for scientists, a theory is a well-substantiated—and testable—explanation that incorporates laws, hypotheses, and facts. The theories of gravity and evolution, for example, aren’t mere hunches; they explain why apples fall from trees and how so many very different plants and animals exist, and have existed, on Earth. According to AMNH’s website, “A theory not only explains known facts; it also allows scientists to make predictions of what they should observe if a theory is true.” Scientific theories are also testable; if evidence isn’t compatible with a theory, scientists can either go back to refine the theory, or reject it altogether.

8. Fossil

As Lowell Dingus, a research associate at AMNH, explains in the video above, fossils aren’t just the remains of hard parts like bones, teeth, and shells. Under the right conditions, organisms’ soft parts—like skin impressions and outlines—can also fossilize. Other things that qualify as fossils are traces made by organisms, like footprints, burrows, and nests. Fun fact: By most definitions, in order to qualify as a fossil, the specimen must be more than 10,000 years old. If they’re younger than that, the specimens are called subfossils.

9. Common ancestor

When you use the term common ancestor, you might mean that one creature evolved from another. But that oversimplifies it: Humans didn’t evolve from monkeys, for example, but share an ape-like common ancestor with Old World monkeys. According to AMNH's website, "Overwhelming evidence shows us that all species are related—that is, that they are all descended from a common ancestor. More than 150 years ago, Darwin saw evidence of these relationships in striking anatomical similarities between diverse species, both living and extinct. Today, we realize that most such resemblances—in both physical structure and embryonic development—are expressions of shared DNA, the direct outcome of a common ancestry."

10. Hominins

Homo sapiens are the only remaining descendants of a once-varied group of primates called the Hominini. You’re probably used to using the term hominids to refer to humans and their ancestors, and not long ago, you would have been correct—but recently, the definition of that word has expanded to refer to all great apes and their ancestors. Instead, you should be using the word hominins to describe the group comprised of modern humans, extinct human species, and our immediate ancestors.

The first hominin fossil was discovered in 1856, and since then, many hominin fossils, comprising many different species, have been discovered. These species emerged in different places over the past six or seven million years, and some of them even lived simultaneously, as AMNH’s Dr. Ian Tattersall explains in the video above.

11. Dinosaurs

We typically say that all dinosaurs went extinct 65 million years ago, but that’s not actually the case. In fact, if you look out your window, you might see one right now. Birds descended from the common ancestor of all dinosaurs, and so, "just as humans beings are a kind of primate, birds are a kind of dinosaur," Mark Norell, curator of the Division of Palentology at AMNH, explains in the video above. So go ahead: Tell your friends that pigeon is a dinosaur. They'll never look at those birds the same way again.

12. Pterosaurs

Chances are, you probably haven't been using this word much at all. That's because most of us grew up thinking that pterosaurs like the pterodactyl were dinosaurs, and that's what we called them. But these animals weren’t dinosaurs, and they weren’t birds, either. They were actually flying reptiles, cousins to the dinosaurs that evolved on a separate branch of the reptile family tree. Pterosaurs were the first animals after insects to evolve powered flight by flapping their wings to generate lift; you can find out more about pterosaurs from the video above.

13. De-extinction

You probably understand what de-extinction is, but you might not understand what kinds of animals we can bring back—and you have Hollywood to thank for that. Despite what you saw in Jurassic Park, scientists will never be able to resurrect non-avian dinosaurs from extinction; any DNA that might be found is just too old to be used. But for other species, science might find a way in the not-too-distant future. In fact, in 2003, researchers implanted a goat egg with genes from an extinct Spanish mountain goat and used a goat-ibex as a surrogate; the resulting animal lived for just a few minutes, but the experiment proved it could be done.

Scientists expect that technological breakthroughs—and genetic data gathered from specimens—will provide ways to revive recently extinct species (think passenger pigeons, and maybe even wooly mammoths). It sounds cool, but de-extinction comes with a number of thorny scientific and ethical questions, as Museum Curator Ross MacPhee explains in the video above.

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DNA Analysis of Loch Ness Could Reveal the Lake's Hidden Creatures
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Stakeouts, sonar studies, and a 24-hour video feed have all been set up in an effort to confirm the existence of the legendary Loch Ness Monster. Now, the Associated Press reports that an international team of scientists will use DNA analysis to learn what's really hiding in the depths of Scotland's most mysterious landmark.

The team, led by Neil Gemmell, who researches evolutionary genetics at the University of Otago in New Zealand, will collect 300 water samples from various locations and depths around the lake. The waters are filled with microscopic DNA fragments animals leave behind as they swim, mate, eat, poop, and die in the waters, and if Nessie is a resident, she's sure to leave bits of herself floating around as well.

After extracting the DNA from the organic material found in the water samples, the scientists plan to sequence it. The results will then be compared to the DNA profiles of known species. If there's evidence of an animal that's not normally found in the lake, or an entirely new species, the researchers will hopefully spot it.

Gemmell is a Nessie skeptic, and he says the point of the project isn't necessarily to discover new species. Rather, he wants to create a genetic profile of the lake while generating some buzz around the science behind it.

If the study goes according to plan, the database of Loch Ness's inhabitants should be complete by 2019. And though the results likely won't include a long-extinct plesiosaur, they may offer insights about other invasive species that now call the lake home.

[h/t AP]

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Essential Science
How Long to Steep Your Tea, According to Science
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The tea in your cabinet likely has vague instructions about how long to steep the leaves. Bigelow, for instance, suggests two to four minutes for black tea, and one to three minutes for green tea. According to Lipton, you should "try singing the National Anthem" while waiting for black tea leaves to infuse.

But while it's true that tea brewed for 30 seconds is technically just as drinkable as a forgotten mug of tea that's been steeping for 30 minutes, drinkable shouldn't be your goal. Taste and—depending on the tea you're drinking—antioxidant and caffeine levels all depend on the amount of time the leaves are in contact with the water. So how early is too early to pluck out a tea bag, and how long can you leave it in before passing the point of no return?

THE SCIENCE OF STEEPING

To achieve the perfect timing, you first need to understand the chemical process at work when you pour hot water over tea leaves. Black, green, white, and oolong tea all come from the leaves and buds of the same plant, Camellia sinensis. (Herbal teas aren't considered "true teas" because they don't come from C. sinensis.) The teas are processed differently: Green and white tea leaves are heated to dry them, limiting the amount of oxidation they get, while black and oolong tea leaves are exposed to oxygen before they're dried, creating the chemical reactions that give the tea its distinct color and flavor. Damaging the tea leaves—by macerating them, rolling them gently, or something in between—helps expose the chemicals inside their cells to varying levels of oxygen.

Both green and black teas contain a lot of the same chemical compounds that contribute to their flavor profiles and nutritional content. When the leaves are submerged in hot water, these compounds leach into the liquid through a process called osmotic diffusion, which occurs when there's fluid on both sides of a selectively permeable membrane—in this case, the tea leaf. Compounds on the surface of the leaf and in the interior cells damaged by processing will diffuse into the surrounding liquid until the compounds in both the leaf and the water reach equilibrium. In other words, if given enough time to steep, the liquid in your mug will become just as concentrated with tea compounds as the liquid in your tea leaves, and the ratio will stay that way.

Osmotic diffusion doesn't happen all at once—different compounds enter the water at different rates based on their molecular weight. The light, volatile chemicals that contribute to tea's aroma and flavor profile dissolve the fastest, which is why the smell from a bag of tea leaves becomes more potent the moment you dunk it in water. The next group of compounds to infuse with the water includes the micronutrients flavanols and polyphenols, which are antioxidants, and caffeine. They're followed by heavier flavanols and polyphenols such as tannins, which are the compounds responsible for tea's bitter flavor. (They're also what make your mouth feel dry after drinking a glass of wine.) Tea also has amino acids like theanine, which can offset the sharpness of tannins.

Water temperature is another factor to take into consideration when steeping your tea. High water temperature creates more kinetic energy, which encourages the compounds to dissolve. "The heat helps you to extract the compounds out of the tea leaves," Shengmin Sang, a North Carolina A&T State University researcher who studies the chemistry of tea, tells Mental Floss. "If you put it into cold water or low-temperature water, the efficiency to extract these compounds out of the leaves will be much lower." But not all water is equal: Bigelow Tea recommends using water at a rolling boil for black tea, and barely boiling water for green tea.

LOOSE LEAF VS. TEA BAGS

Osmotic diffusion takes place whether you use loose leaves or tea bags, but there are some notable differences between the two. When given room to expand, loose tea leaves swell to their full capacity, creating more room for water to flow in and extract all those desirable compounds. Tea that comes prepackaged in a bag, on the other hand, only has so much room to grow, and the quality suffers as a result. This is why some tea companies have started selling tea in roomier, pyramid-shaped bags, though the size matters more than the shape.

But even before the tea touches the water, there's a difference in quality. Loose leaf tea usually consists of whole leaves, while most teabags are filled with broken pieces of tea leaves called dust or fannings, which have less-nuanced flavors and infuse fewer antioxidants than whole leaves, no matter how long you let them steep.

So if you have a choice, go with loose leaf. But if tea bags are all you have on hand, don't bother adjusting your brewing method: The difference in taste and antioxidants isn't something that can be fixed with a few extra minutes, and according to Sang, you should follow the same steeping times for both tea bags and loose leaf.

To calculate the perfect brew times for what's in your mug, first consider what you want most out of your drink.

IF YOU DRINK TEA TO BE HEALTHY

Suggested steeping time: 2 minutes, 30 seconds to 5 minutes

Tea leaves are packed with beneficial compounds. Research indicates that flavanols such as catechins and epicatechins, found in both green and black teas, help suppress inflammation and curb plaque build-up in arteries. Drinking tea may improve vascular reactivity, which dictates how well blood vessels adjust to stress. According an analysis of multiple tea-related studies published in the European Journal of Epidemiology in 2015, drinking three cups of tea a day reduces your risk of coronary heart disease by 27 percent, cardiac death by 26 percent, and total mortality by 24 percent. Polyphenolic antioxidants in tea may also protect against diabetes, depression, and liver disease.

Past research has shown that it takes 100 to 150 seconds to extract half the polyphenol content from green and black tea leaves. According to a study published in 2016 in the journal Beverages, you can get more polyphenols into your drink if you allow the leaves more time to steep. However, the returns may not be worth the extra effort: Most of the compounds the researchers measured after 10 minutes of steeping were extracted in the first 5 minutes.

Sang makes another argument for not waiting too long to drink your tea. Antioxidants are slightly unstable, which means they will eventually break down and lose their healthy properties after infusing with water. “After you extract the compounds from the tea bag, you can not keep the solution for too long,” he says. “Because these compounds are not stable, they will be oxidized. So if you brew it in the morning, then you drink it in the afternoon, that's not good.” This oxidation can occur even after the tea leaves are removed from the cup, so if your tea has been sitting out for a few hours, it's better to brew a new batch than to pop it in the microwave.

IF YOU DRINK TEA FOR THE CAFFEINE BOOST

Suggested steeping time: 3 to 5 minutes

Though less potent than its rival coffee, a properly brewed cup of tea packs a caffeine punch. According to a 2008 study published in the Journal of Analytical Toxicology [PDF], letting your tea brew for at least a few minutes has a big impact on the caffeine content. The study found that after brewing for one minute, a cup of regular Lipton black tea had 17 milligrams of caffeine per 6 ounces of water, 38 milligrams per 6 ounces after three minutes, and 47 milligrams per 6 ounces after five. (The nutritional information for Lipton black tea says a serving contains 55 milligrams of caffeine per 8 ounces, so it's pretty accurate.)

Some people may use those numbers as an excuse to steep their tea past the five-minute mark in an attempt to reach 100 percent dissolution. But a longer brewing time doesn't necessarily equal a stronger caffeine kick. Yes, more caffeine molecules will enter the tea, but so will other compounds like thearubigins. Caffeine works because it's perfectly shaped to bind to certain neuroreceptors in your brain, thus blocking the chemicals that tell you to feel tired. But caffeine is the right shape to bind to thearubigins as well, and if that happens first, less caffeine will get to those neuroreceptors. So if you're looking for a highly caffeinated cup of tea, you should remove the leaves after most of the caffeine has been extracted—after about three to five minutes—rather than waiting for every last milligram of caffeine to dissolve.

IF YOU DRINK TEA BECAUSE IT TASTES GOOD

Suggested steeping time: 1 to 3 minutes

There's nothing wrong with enjoying a cup of tea for taste alone. Flavor is the most subjective factor influenced by steeping times, but for the sake of simplicity, let's assume you prefer a pronounced tea taste that's not overshadowed by bitterness. To extract those more delicate flavors, you don't need to steep your tea leaves for very long at all. Some of the first volatile organic compounds to break down in tea are geraniol and phenylacetaldehyde, tied to a tea's floral aroma, and linalool and linalool oxide, which give tea its sweetness.

The other compounds we associate with tea's distinctive taste are tannins. They're the difference between an aromatic, fruity cup of tea and a bitter cup that needs to be diluted with milk before it's palatable. But tannins aren't all bad: Some people prefer their tea to have a bracing astringency. Because tannins are some of the last molecules to dissolve into tea, if you want to add some bitter complexity to your drink, steep your tea for a minute or two longer than you normally would. A good way to keep track of the strength of your tea is to look at the color: Like tannins, pigments are heavy compounds, so if you see your tea getting darker, that means it's getting stronger as well.

And what about herbal teas? Feel free to leave the leaves in as long as you like. Because herbal teas are high in aromatic compounds and low in tannins, drinkers can be more liberal with their steep times without worrying about getting that astringent taste. Some teas, like rooibos and chamomile, also contain antioxidants, which is another reason to take your time.

And if you're new to the world of tea and aren't sure what your preferences are, put a kettle on the stove and start experimenting.

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