Innholdsfortegnelse for March/April 2017 i Popular Science

IT TOOK 3 3 8, 303,000 gallons of water to make this issue—give or take some sweat and tears. No, we didn’t pioneer a way to turn water into journalists and then kick back and watch ol’ H20 dedicate an entire magazine to itself. But we did drink water as we brainstormed, reported, designed, wrote, copy-edited, photographed, fact-checked, and so on. And I’m happy to report that everyone showered, washed their clothes, and went to the bathroom regularly. We probably all directly consumed close to the American average of 100 gallons of water per day. But that is—and I’m really sorry for this next phrase—just a drop in the bucket. As Sarah Scoles reports (p. 58), the average American actually uses about 2,088 gallons in 24 hours. Because it’s not…

1 STAGE Thirst WATER LOST 2% of body weight. For a 170-pound person, that’s 3 pounds. You might lose this much sweat by kickboxing for an hour in a hot room without a drink. EFFECTS When thirst kicks in, your body clings to all remaining moisture. Your kidneys send less water to your bladder, darkening your urine. As you sweat less, your body temperature rises. Your blood becomes thicker and sluggish. To maintain oxygen levels, your heart rate increases. 2 STAGE Fainting WATER LOST 4% of body weight. For a 170-pound person, that’s 7 pounds. This is roughly equivalent to riding a bike for three hours in extreme heat without rehydrating, or going without water for two days. EFFECTS Your blood is so concentrated that the resulting decrease in blood…

595–685 B.C. Amphicitionic League vs. Kirrans Pilgrims visiting the Oracle at Delphi had to pass Kirra, a coastal city where thieves often robbed the travelers. To end these attacks, Greek tribes formed a league to besiege Kirra. They poisoned its water with hellebore, a toxic herb that sickened citizens until the village fell. 51 B.C. Romans vs. Gauls To drive the Gauls from what is now France, Roman troops had to attack their last remaining fort on the Dordogne River. During the siege, archers shot any Gaul trying to escape. Then, the Romans drained a spring that fed the fort its water. The thirsty Gauls ultimately surrendered. 30 A.D. Romans vs. Jews When Pontius Pilate, the Roman governor of Jerusalem, stole funds from a Jewish temple to build…

Electricity-Generating Rain Gutters @CHUBBS5740 VIA TWITTER Possible? Absolutely. Effective? Not so much. To generate enough hydropower to charge anything, you’d need a lot of downward pressure, says Bob Bass, a power engineer at Portland State University. “In a rain gutter, you don’t have that push.” You could create it by storing water on the roof, but the main problem is simple: “It doesn’t rain that much.” The best you could do with the power is run some LED lights. But don’t expect to find one in stores anytime soon. Lawn-Watering Robot That Finds Dry Spots MIKE JACOBELLIS VIA EMAIL Soon, you may be able to plant a few sensors, no robot necessary. Engineer Jim Canyon’s prototype measures the soil’s ability to store electric energy. Higher numbers mean wetter soil, since…

10L Broccoli Broccoli seems like a wonder food, based on the calories you get out for the water you put in. And even though 100 calories of the veggie weighs in at more than half a head, this crunchy snack doesn’t need a ton of flow to grow. 180L Chicken Chickens not only drink water, but they also munch water-requiring feed. But they don’t do so for long: The average broiler takes a mere five weeks to reach its market weight of 5 pounds. After that, the eater becomes the eaten. 170L Apples Apple trees are picky growers: They don’t thrive in too-wet soil, but they do require irrigation in too-dry soil. Yet, on the liters-per-100-calories scale, they use nearly as much water as chicken. That’s because the fruit provides…

MORE THAN 660 MILLION people lack regular access to clean drinking water. And by 2030, half of humanity will live in areas where the demand for water outstrips the available supply. That’s why entrepreneurs Nancy Curtis and Don Zacherl from Vici Labs are experimenting with a device they call Water-Seer, which pulls moisture out of the air using nothing but wind power and basic physics. The air is full of water vapor. Chill that vapor, however, and the water will condensate into a liquid. This principle makes water bead up on the outside of a frosty glass—and it also drives WaterSeer: The device sends air underground, where cooler temperatures turn the water from gas to liquid. Field tests suggest that WaterSeer can produce up to 11 gallons of fresh drinking…

1 Desk Jockeys Be an adult: Drink from a glass. The MIU Color 18.5-ouncer is made of borosilicate, which, thanks to a makeup that’s about 5 percent boric oxide, is durable and stain resistant. 2 All-Day Toters Most doublewalled bottles use hefty endcaps to close the chamber between the steel walls. Hydro Flask seals with a glass plug during the vacuuming process, lightening the vessels. FROM $22 3 Trail Trekkers When climbing, it can be hard to breathe, let alone pull water from a hydration pack’s straw. The Geigerrig Rig 700M is pressurized: Bite a valve to get H2O from its 70-ounce reservoir. $140 4 Gym Rats Swag canteens are great—if you’re into lukewarm water mid-workout. The Camelbak Podium Chill sport bottle’s cell-foam insulation keeps water cold twice as long…

GOOD Delta In2ition H2Okinetic Five-Setting 2-in-1 Shower Rather than push water through pinholes to create the illusion of pressure, Delta engineers steer the liquid into waves to give the feeling that there’s more H2O than there is. Based on the fluidics that help windshield nozzles spray evenly, the In2ition head circuits water through a series of internal dams to make concentrated, body-covering droplets. $100 BEST High Sierra ReflectionsX It will take all 20 fingers and toes—if not more—to count the nozzles on most showerheads. On a High Sierra head, you’ll see only one. Inside the sole nozzle, a horizontal pin separates water flow into two streams. The cone-shaped opening directs them to collide with one another, which forms a drenching, rainlike spray. It feels like a hose, but uses as…

PESTICIDES Insecticides and herbicides can wash into rivers and lakes and seep into groundwater. The pesticide atrazine has been linked to hormonal imbalances in lab animals but probably isn’t carcinogenic. FLUORIDE As rocks erode, they naturally release fluoride into soil, air, and most water sources. Because it can prevent tooth decay by rebuilding enamel, many communities add extra to the drinking supply. CHLORINE Water-treatment facilities add chlorine as a disinfectant, and it’s safe at low levels. But some disinfectants produce byproducts that have been linked to miscarriages. ARSENIC Arsenic occurs naturally in rocks and soil, and it’s linked to increased risk of cancer. A water-treatment plant should remove the poison, but private well owners must periodically test for HYDROGEN SULFIDE Naturally occurring and harmless, this chemical is still a pain…

Among Hawaii’s reefs, Emily Kelly dives with surgeonfish and parrotfish. By grazing on fleshy algae, these “underwater lawnmowers” make room for hard corals to grow. To study how the fish aid the reef, and how to protect them from overfishing, Kelly uses this collection of gadgets and gizmos. Wetsuit Even in Maui’s balmy 75- to 80-degree waters, up to eight hours a day in the water saps Kelly’s body heat. A wetsuit keeps her cozy. GPS Unit Scientists can’t exactly mark a fish’s street address. So they use a civilian GPS unit to track where they make observations and find specimens. Coolers The researchers preserve specimens on the way to the lab in an ice-filled cooler. A similar cooler holds snacks. The trick is remembering which cooler is which!…

When we fly Hurricane Hunter aircraft into cyclones, a lot of the data we gather is to monitor for “rapid intensification.” That’s when a storm increases in strength by 35 miles per hour or more within a 24-hour period, and it’s a big concern for the forecast community. The nightmare scenario is for this to happen to a Category 1 hurricane just before landfall on the U.S. coast: It goes from a Category 1 to a catastrophic Category 4, and no one has any warning. Back in 2007, during Hurricane Felix, we flew into a Category 2. But at 10,000 feet, I saw flashes—at first I thought someone took a photo, but then I realized it was lightning. When you see lightning in the core of a storm, it’s a…

About 25 years ago, some people would turn on their faucets and smell cat urine. It was one apartment in a building, or one house in a neighborhood. Residents would say, “We don’t have a cat.” We were stumped for more than a year until a utility employee sai d, “It’s not our water; it’s residents’ new carpets.” He was half right, anyway. At the time, maybe 0.1 percent of utilities in the United States disinfected their water with chlorine dioxide. But chlorine dioxide isn’t water soluble, so when people opened their faucets, it would quickly fill the surrounding air. There, it reacted with chemicals in new carpets to create the signature stench. My colleague and I went to his church, which had a new carpet, to test the theory.…

If you Google: Nursing Sisters Port Dover, you’ll see a book by Harry B. Barrett. In that book are pictures of my grandmother and her heroic nursing sisters during WWI, including one sister who was mentioned in wartime dispatches for her heroism along with a certificate presented to her by King George V. (In spite of her “valor in the face of the enemy,” a woman was ineligible to receive the Victoria Cross!) There are hundreds of letters and pictures, including one of the ambulances my grandmother donated (before we entered WWII ) encouraged by her friend, suffragist CARRIE CHAPMAN CATT, who moved around the corner from my grandmother in New Rochelle, N.Y. As a youngster, I remember all the sewing machines and their many friends at my grandmother’s house…

Flint, MI 4 The number of standard-size (16.9-ounce) bottles of water an average adult needs to drink daily to prevent dehydration. 757 The number of bottles it would take to substitute all of a standard American’s daily water usage, including showering and tooth brushing. 14 The number of bottles the state should give a Flint resident daily; the result of a lawsuit from the American Civil Liberties Union, and others. 100 The number of bottles it reportedly took some Flint families to make Thanksgiving dinner in 2016. One needed 24 bottles just to thaw the turkey. 60 The number of bottles needed to cook—and clean—per day for one Flint family of three, who tracked how much water they used, and for what. 750 The number of water bottles that Flint’s…

San Joaquin-Sacramento River Delta Water enters this network of channels via two of California’s largest rivers: the San Joaquin and the Sacramento. Some of that fresh water then flows into the 444-mile-long concrete-coated California Aqueduct. Local Groundwater Some cities in LA County still extract water from within sediment layers. They take it from basins overseen by court-appointed “water masters,” pump the liquid up to the surface, treat it, and send it flowing into the system. Desalination With so much ocean nearby, why does LA import water at all? Because desalination guzzles a lot more energy and money than relatively passive aqueducts. A fancy desalination plant opened in Carlsbad in 2015, but it supplies Southern California a relatively low volume. 16 minimum number of days water requires to travel the length…

OUTSIDE THE WINDOW OF HELEN DAHLKE’S OFFICE, AT THE University of California at Davis, the clouds hang low, their edges seeming to brush against the building. It’s raining intensely, an unusual event in a perpetually parched state suffering from a five-year drought. “It looks like the end of the world,” says Dahlke happily. As a hydrologist and professor who studies how water flows over and through rock, soil, fields, and farms, she is something of an H2O whiz. For the past two years, Dahlke has spent days like this doing what water conservationists might find abhorrent: standing in the rain, in knee-high rubber boots, opening sprinklers on a dormant farm or orchard, and letting them spray. She’s good at it. She can spray about 45 million gallons in 42 days.…

THE FUTURE Is Clear Transparent ice takes time. You either carve the clear center of a huge block or use insulation to slowly solidify so the water comes out crystal. 2000S Going Soft Slick silicone has a low coefficient of friction and a pliable nature. Both let you create otherwise impossibleto-release shapes with ease. 1980S Topping It Modern plastics don’t crack as easily as the old stuff, but the genius award goes to lidded trays: You can stack them before the water sets. 1960S Plastics Injection-molded polymers changed every industry, ice included. Trays graduated from skin-chilling metal to twistable polypropylene and polyethylene. 1930S DIY Cubes With the advent of refrigeration, you could freeze your own ice in aluminum trays; the metal warmed as it left the freezer, releasing cubes easily.…

½ ROLLS OF TOILET PAPER SAVED PER PERSON PER WEEK Assuming a healthy digestive system, opting to clean up using the Neorest’s three bidet hoses will use just four gallons per person per week. It takes 18.5 gallons to make a half-roll of TP. 4 WEEKS ONE OFFICE WENT NOT CLEANING THE TOILET To stop buildup, preand post-squat mists of acidic, electrolyzed water rinse the bowl. Then, zirconium in the glaze—activated by an underlid UV light—breaks down any stuck-on gunk. 45 PERCENT DROP IN WATER USAGE WITH EFFICIENT FLUSHES Dual nozzles turn 0.8 gallons of water into a vortex to wash away number ones. Sit more than 30 seconds, and presence and bodyheat sensors infer a number two, signaling a full-gallon flush. 20 OUNCES (EST.) OF WATER IN A BOTTLE…

ONE SATURDAY MORNING IN DECEMBER, I drank half as much coffee as usual and then, dull-eyed, walked to a hardware store to purchase the 18-gallon storage container I would use to take showers for the next seven days. Because for one week, I was going to shrink my water footprint to see how that small shoe felt. Much of my home state of Colorado is in a drought. Last May, when I moved to Denver, where I share an apartment with my sister, Rebekah, the locals promised me snow by October. None fell till mid-November. Rainfall was about half the amount normal for fall. I’d come from California, where drought is so severe that lawns have turned brown and swimming pools go unfilled. Colorado isn’t that bad yet. Neither is…

From salvaging wrecks to building aquatic infrastructure, master divers like James Emerson handle some of the U.S. Navy’s most complex subaqueous projects— because if something is tricky on dry land, it can be diabolical in the drink. Emerson is in charge of turning Seabees (the name comes from the abbreviation for “Construction Battalion”) into underwater experts. Out of 160 Seabee divers, only 2 to 4 percent will ultimately earn the title of “master.” 1 Join the Seabees Enlisted sailors learn construction and demolition, without the added pressure of doing it underwater. 2 Become a Seabee Diver Now to perform those same tasks in scuba gear. Lessons include hydraulic cutting and welding—and avoiding electrocution. 3 Learn on the Job One of Emerson’s first tasks was to cut up…

Kumud Acharya seeks out the world’s hottest conditions. Here’s what he brings to stay hydrated— and alive—while doing science in the most scorching environments. 1 Reusable Bottles Acharya drinks from the tap when it’s safe, and bottled or purified when he’s not accustomed to the local aquatic flora. For a day’s work, he’ll bring four to five liters in reusable vessels in a cooler full of ice. 2 Skin Coverage To prevent painful sunburns, Acharya applies spray-on, waterproof sunscreen copiously and often. He also wears long-sleeved shirts and large-brimmed hats with neck covers for more protection. 3 A Small Tent It’s important to get out of the rays periodically, and the desert isn’t famous for its shade-giving trees. Acharya brings his own shelter. While he rests, he reslathers…

CHANGE OF SCENERY through the looking glass trip meter WHY DO THE BLACK AND WHITE BARS on this piece of patterned paper seemingly switch direction? The answer lies in the shape of the glass—and what’s inside. First, a few basics about how you perceive the world. Typically, light bounces off an object and hits your eye in a straight line. But when light waves have to travel through a medium thicker than air, they move more slowly. In this case, the water inside the glass has pumped the waves’ brakes. That change in speed causes a redirection, or bend, of the wave, a process known in physics as refraction. You might remember this concept from high school science classes. Well that’s only half the story. Think of the glass as…