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Popular Science March/April 2017

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United States
Camden Media Inc.
4 Issues

in this issue

2 min
life is thirsty

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 just the…

2 min
moisture misers

1 Kangaroo Rat The kangaroo rat never has to drink water—it just gets it from the seeds it eats. To survive in the dry climes of the American West, its kidneys generate super-concentrated urine, and it doesn’t pant or sweat. Some species can even lower their metabolic rates so they lose less moisture through breathing. 2 Camel Camels don’t actually store water in their humps, so they have to conserve it. At night, after the chilly Saharan air cools the camel’s nasal cavity, mist in its breath condenses inside its nose, where it gets reabsorbed. The camel’s extra-twisty nasal passages save up to 60 percent of the moisture it would have lost during exhalation. 3 Water-holding Frog During hot, dry periods, this Australian frog secretes a waterproof mucus cocoon that prevents moisture from escaping its…

1 min
flint: a day by the bottle

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 Durant-Tuuri-Mott Elementary School uses daily—that’s a…

2 min
the water (re)cycle

1 Out with the Old Your urine is more than 90 percent water (and your poop is about three-quarters). Each time you flush, the sewer system ferries your waste—along with 1.6 to 7 gallons of perfectly good H2O used to swirl it down your porcelain throne—to a treatment plant designed to make it taste delicious. 2 Catching the Big Stuff Treatment plants employ a series of mesh screens to catch rocks, sticks, and other—ahem—larger refuse floating in your former toilet juice. Finer debris sinks down to the bottom of deep pools, while the top layer flows through. Some municipalities also add chemicals that clump crud together, which makes it easier to catch and remove stowaway stools. 3 Taking a Closer Look “Activated sludge” sounds nasty, but this mushy mix of bacteria actually helps break down…

2 min
but how much does food drink?

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 less energy. 55L Wheat Flour Wheat usually grows in spring and…

2 min
la’s far-ranging roots

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 of the California Aqueduct Eastern Sierra Snowmelt from…