Innholdsfortegnelse for Fall 2021 i Popular Science

WE HUMANS SPLIT FROM our hominid ancestors around half a million years ago, creating a new branch in the tree of life. Natural selection, genetic mutations, and geographic separation can create these new limbs, but just when they sprout remains widely debated. Biologists long thought it occurred when individuals from two groups could not produce fertile offspring, but hybrids like ligers throw even that basic construct into question. The changes at work in DNA are still largely unclear, so studying recent arrivals like these offers insights into budding species. Nylon-eating bacteria In 1975, Japanese scientists discovered a bacterium that digests the synthetic byproducts of nylon manufacturing—substances created just four decades earlier. They found that a few key mutations in the genetic code of Paenarthrobacter ureafaciens KI72 helped produce these plastic-eating…

For the beginner Dell designed the Chromebook 3100 to endure the gauntlet of elementary school. With its stout plastic chassis and rubberized edges, this 11.6-inch machine is tough enough to survive a 30-inch fall. Covered ports and a sealed keyboard ensure that a catastrophic juice box failure won’t land this machine in the repair shop. For the power user Google’s Pixelbook Go offers many of the same specs found in top-tier Windows laptops, but it weighs just 2 pounds. The flagship includes a burly Core i7 processor, a generous 16GB of RAM, and a roomy 256GB solid-state drive. Its 12-hour battery life is enough for a full day of studying—or procrastinating. For the aspiring creative Thanks to its 4,096 levels of pressure sensitivity, the pen nestled in the body of…

FROM ROME’S VAST TRAJAN’S FORUM to Angkor Wat’s stone temples, cities have been magnets for trade, art, and culture since ancient times. Urban living as we know it first emerged around 3500 B.C.E. along the Nile Valley and Sumerian coast. Unlike the semipermanent villages that came before them, these social and political hubs were built around sophisticated systems of agriculture and transportation. Today, around 56 percent of the world’s population is urban, and by 2050 that number could jump to around 70 percent, by some estimates. While metropolises continue to serve as centers for economic growth, they’re also facing unprecedented challenges: affordable housing crises, unemployment, healthcare shortages, food and water scarcity, and social inequity. They’re also on the front lines of climate change. With 90 percent of all urban areas located…

YOU DON’T HAVE to spend hours sweating in the gym each day to lead a long, healthy life. A few simple lifts and stretches can help maintain strength, improve mobility, and prevent aches as you age. The key is to focus on what some trainers call “functional fitness”—exercises that translate to everyday tasks like hauling groceries and taking out the trash. A move called the weighted carry is a good place to start. Take a dumbbell in each hand, hold them at your sides, keep your spine straight, and walk. A trap bar dead lift imitates lifting something off the floor, working the legs and back. And squats are another great exercise, as they reinforce the lower body by mimicking rising from a chair. Stretching is also essential because it…

RIGHT AFTER BABIES ARE BORN, every stimulus around them helps shape their squishy brain. This is why it’s important to keep them interacting with their surroundings as much as possible in a safe way. Enter the mobile, a vibrant gizmo with hanging objects that will provide your child with hours of entertainment even when they’re doing nothing but lying snugly in the crib. In their first year of life, infants move through multiple cognitive stages and developmental milestones. That’s why the best mobiles grow along with them, and this homemade one does the trick. Time: 1 hour Cost: $45 Difficulty: Easy Materials: Flexible metal electrical conduit Spring clamp String 24 inches of 10-gauge copper wire Electrical tape An 8-inch wooden hoop Items to hang from the mobile Tools: Metal hacksaw Measuring…

THE BEST PLAY AREAS offer more than recreation. They provide children with a dynamic classroom in which to hone motor skills, test boundaries, and learn conflict resolution. Yet child development experts and architects alike agree that many of the spaces we have now don’t always facilitate the kind of rich, meaningful play that provides those lessons. They say these six components are critical to creating the ideal outdoor experience—and to making recess as entertaining as possible. Little ones exercise their innate creativity by working with materials and tools to craft ever-changing adventures. Things like crates, tires, sand, and water allow active minds to devise and revise all kinds of engaging activities alone or with others. Allowing rugrats to take age-appropriate risks builds confidence. Fast slides, big swing sets, and plenty…

An upscale version of the sweaty cheese and meat blocks of yore, Columbus Charcuterie Tasting Board feature combinations like Italian salami, white cheddar, and dark chocolate–covered cranberries. To make Chickpea Snacks satisfy cravings for something crunchy and salty, Biena slow roasts organic legumes in sunflower oil, then dusts them in savory flavors like barbecue and habanero. A proprietary dehydration process keeps the mango, banana, and pineapple in Solely Fruit Jerky chewy and sweet—without the added sugar and chemical binders often found in similarly sticky treats. Ripple Dairy-Free Pea Milk contains one-third the sugar of the real thing. Making it also requires just 17 percent of the water required for almond milk, and the fact that it’s nut-free means it won’t trigger allergies. Bobo’s Toast’r Pastries ditch the frosting, but you won’t…

1. Brave Justice Snack Attack Five flexible flaps let little hands reach through this collapsible container’s lid without removing it, keeping Cheerios off your upholstery. It holds up to 8 ounces of a kiddo’s favorite food and fits in car cup holders. 2. Alvababy Wet Dry Bag These waterproof lined polyester totes are roomy enough for a day’s worth of dirty cloth diapers. A second spacious zippered compartment provides stowage for clean duds or befouled outfits. 3. OXO Tot-on-the-Go Wipes Dispenser A sturdy plastic loop allows this container to dangle from a backpack strap. The push-button lid opens with a single snap, allowing quick access for emergency mop-ups. 4. Babyganics SPF 50 Sunscreen This lotion combines ray-blocking titanium dioxide and zinc oxide with tomato, sunflower, cranberry, and other oils to…

FRESH EYES can change the world, and a world stressed by a pandemic, climate change, and inequity is one more ripe for change than we have ever experienced before. That’s why, after a five-year break, Popular Science is bringing back the Brilliant 10: an annual roster of early-career scientists and engineers developing ingenious approaches to problems across a range of disciplines. To find those innovators, we embarked on a nationwide search, vetting hundreds of researchers from institutions of all stripes and sizes. These thinkers represent our best hopes for navigating the unprecedented challenges of tomorrow—and today. MAKING FUTURE FORECASTS LESS HAZY ALLISON WING SEES a hole in the world’s major climate models: The reports published by the Intergovernmental Panel on Climate Change factor in water vapor, but not the way…

FROM THE MID-1960S to the early 2000s, cassettes reigned supreme with audiophiles thanks to their portability, low price, and crisp sound quality. They eventually lost their throne (first to CDs, and then to MP3s and streaming platforms), but they recently became trendy again. Before you rush out to buy one of these retro devices, however, just know you’ll need a few tools to help you enjoy the full tape deck experience. A / SPARE BATTERIES Cassette players typically use a pair of AAs or AAAs to roll the tape across a magnet at 1.875 inches per second. As the power drains, the sound becomes unstable. Stashing a couple in your pocket or purse can save you on the go. B / WIRED LISTENING DEVICE Some modern decks may be Bluetooth…

IN MOST CASES, a tyke’s refusal to tuck into certain dishes is a normal phase that will eventually pass. But sometimes, the habit persists well into adulthood, making every dinner a challenge. These three tips will get anybody—from youngsters to elders—to chow down. MAKE MEALTIME FUN Parents should introduce flavors by offering children small bits to study, smash, and taste. Older kids and grown-ups should venture into the kitchen, as they’re more likely to try grub they’ve helped prepare. Cute dinnerware also makes things more tempting. STIR IN SMALL CHANGES Add new foods to known favorites by, say, sprinkling some chopped broccoli over mac and cheese or pairing shellfish with mashed potatoes. Patience and familiarity are key, especially with children: It can take as many as 10 encounters for them…

WHEN THE COMMON ERA STARTED a little over two millennia ago, as few as 170 million Homo sapiens lived on Earth. Except for the notable dip caused by the bubonic plague pandemic of the 14th century, that number grew steadily through 1800 to about 910 million. It has since exploded to almost 8 billion. It seems logical to assume the planet will only grow more crowded. Yet global average birthrates have dropped by half since 1968, to 2.4 children per woman. Nations facing steep declines find this worrying, because dwindling populations can stymie economic growth. But demographers say the trend is neither good nor bad. It simply reflects the ongoing improvements in the lives—and livelihoods—of childbearing women and kids everywhere. Here’s a look at some factors driving the change. Home…

WHEN FEIGE WANG WAS GROWING UP in Shandong province, China, he liked gazing up at the night sky to look at the stars. Now, as a NASA Hubble fellow at the University of Arizona’s Steward Observatory, he looks much deeper into the darkness to contemplate the most distant objects ever studied. His targets, quasars, are black holes surrounded by disks of gas and stars—the nuclei of primitive galaxies. Their dark hearts suck in nearby matter and crush the absorbed material into a superhot disk, which burns bright as it shoots out immense amounts of energy. That’s the feature that allows us to spot them from so far away. But because it takes billions of years for their light to reach Earth, we see these beacons in the blackness as they existed…

“CAN YOU SAY MAMA? Or dada? Wave bye-bye!” If you’ve spent any time around a baby, chances are you’ve heard or said things like this. The high-pitched, singsong tone we switch to when interacting with young children can go by many names—baby talk, parentese, or, according to development specialists, infant-directed speech. But as simplistic as this melodic chitchat might seem, the conversations are crucial. Baby talk is an essential piece of speech and language development. Studies show that when infants are exposed to daily doses of it throughout their first year of life, they develop more robust vocabularies than other kiddos. And the little ones are eager for it: The distinct tone of parentese grabs their attention, recent research shows, allowing them to reap the benefits. By analyzing the jabber…

Two sets of bearings in the RPM Session4’s machined-aluminum handles keep things twirling at max speed with minimal resistance. To ensure proper hopping clearance, snip the 12-foot braided steel cable so that its ends reach your armpits when you stand on the rope. The 36-inch Healthy Model Life fitness hoop, available in 2- and 3-pound weights, works just like the loop you had as a kid but requires more effort to keep aloft. Thick foam cushions your torso during long sessions, and the whole thing snaps into eight pieces for easy transport. Bouncing burns about 1,000 calories per hour, and the Marcy Cardio Trampoline Trainer’s 40-inch pad is small enough to use anywhere. Its wide elastic bands support jumpers up to 250 pounds, and the nylon mat won’t sop up…

CATERPILLARS ARE MASTERS OF DECEPTION. Some imitate sticks and leaves to avoid becoming lunch. Others flash bright colors to convey their toxic nature. A few even wave pumped-up limbs to frighten foes. ¶ Despite such impressive maneuvers, humans tend to overlook these wee wonders. But they rarely escape the eye of Samuel Jaffe, an entomologist who’s spent his life uncovering their anonymous exploits, a fascination that began when he was a kid collecting the critters near his Massachusetts home. ¶ Before long, Jaffe started photographing them. In 2013, that project blossomed into the Caterpillar Lab, an education center in New Hampshire with thousands of live specimens. The nonprofit’s scores of caterpillar close-ups provide a fascinating glimpse of the secrets hiding in backyards everywhere, just waiting to be found. Baltimore checkerspot…

MERRY-GO-ROUNDS WERE ICONIC in the hearts and minds of kiddos and grown-ups alike after the turn of the 20th century. Walt Disney cited the spinning spectacles as his inspiration for the Happiest Place on Earth, and carnival folk dubbed them “the First Ride.” During this golden age of carousels, Popular Science even offered readers instructions for building their own. But given that fewer than half of American homes had access to electricity at the time, that 1919 model got its power from the wind. Before electrification in the late 19th century, manual cranks, pedals, mules, and, eventually, steam spun the whirling stages, which sported simple features like suspended seats and benches. Voltage allowed designers to introduce the classic bobbing horses, organ music, festive lights, and double decks. But appetites for old-school…