Popular ScienceJune 2014的目錄

Feed 08 From the Editor 10 Peer Review 12 A Bit About Us Now 15 A tiny camera that sees everything 16 A no-compromise surfboard 18 A new breed of game console 19 A V-4 with the oomph of a V-6 20 The physics of the new World Cup ball 21 Ten things we love this month 22 The smart way to drink coffee 25 Putting a price on online privacy Next 27 NASA's rocky relationship with Russia 28 The most interesting parts of the sky 29 A high-capacity, high-efficiency jumbo jet 30 Tips from a steam-engine mechanic 31 The surprising science of bubbles 32 Why forensics is flawed Manual 63 A Transformers suit built to deceive a Decepticon 64 How to find food, water, and shelter while lost at…

The article on Noah Fierer's study of microorganisms in our environment [“Invisible World,” April 2014] is very interesting. Few realize how many living creatures surround us and even live on or in us. In the seventies, a local television station refused my images of microorganisms in milk products, arguing that yogurt producers would sue the station if people stopped buying yogurt because they were shown that it contained lactobacilli and streptococci. Now things have changed—microorganisms can be seen with scanning electron microscopy. Miloslav Kalab Ottawa, Ontario…

Since the late fifties, generations of surfers have come to love the feel of foam-and-fiberglass boards. But the boards have their flaws: They're heavy, and fiberglass shells ding easily. New carbon-fiber decks fix both problems, but surfers don't like the way they ride—too stiff. The Starboard Hybrid is the best of both worlds. It's 20 percent lighter and up to three times stronger than classic boards, yet it feels like good old foam-and-glass on the waves. A carbon-fiber I-beam runs lengthwise down the centerline. It makes the board strong enough to resist breakage in extreme events—say, when a large wave detonates on top of the board—but because it's underneath a shock-absorbing foam layer, it doesn't affect the ride under normal conditions. Engineers inject ultralightweight expanded polystyrene (EPS) foam into a…

Carmakers have long followed a simple rule: To increase power, make the engine block bigger. Volvo is doing the opposite. It's phasing out five- and six-cylinder engines in favor of four-cylinder ones that are nearly 100 pounds lighter yet produce the same horsepower. The Drive-E is one such engine and is available in the S60 sedan now. To overcome the inherent power deficit, engineers did something unusual: They added a turbocharger and a supercharger. The supercharger kicks in immediately to add power at low speeds, where most small engines feel weak. This buys time for the turbocharger to engage once the engine revs up. The system is part of a larger trend among many U.S. automakers that promises to make internal combustion engines more efficient, since, like it or not,…

There's the barista at the corner coffee bar who knows your order and always has it ready. Then there's the Mr. Coffee Smart Coffeemaker ($150; available fall), which does the same thing in your own kitchen. The pot connects to an app over Wi-Fi, so you can control the brewing schedule, check water and grounds levels, and turn the machine off and on from anywhere. The average Swede drinks four cups of coffee every day. That's 1,460 cups a year, about twice as much as the average American. Below, dots plot drinks' caffeine content, and lines show overall range, according to the Journal of Analytical Toxicology. Energy drinks, 8 different brands Fountain Coca-Cola at 9 fast-food joints 16-ounce Starbucks coffee, on 6 days Lipton tea steeped for 1, 3, or…

Last year, a group of astronomers in the U.S. and Germany made a new kind of sky map, which charts the how intensely scientists study features in the heavens. To build the map, they analyzed a million references to celestial objects in a NASA database of journal articles. Astronomers can use the online version to find data. To the rest of us, the map reveals the most intriguing parts of the universe. Stripes are areas where astronomers carefully sample transects of the heavens. The Sloan Digital Sky Survey made this particular one in the early 2000s. In 1995, the Hubble Space Telescope stared at this seemingly empty patch for more than 200 hours. It revealed a staggering number of galaxies and changed how astronomers understand the universe. The Kepler telescope…

Bubbles may seem pretty ordinary. We tend to think of them just as beverage enhancers or entertainment for small children. But scientists are uncovering another side to bubbles: They can perform computations, drive climate, and even act as weapons. “I could teach an entire course on bubbles,” says James Bird, a mechanical engineer and bubble expert at Boston University. “The more I learn about them, the more I realize how much we don't know.” Here, in celebration of summer, the unofficial season of the bubble, we offer a glimpse into the hidden world of this common, albeit little understood, form. Scientists have found that when a mantis shrimp strikes, its claw pulls water molecules away from one another, creating a pocket of low pressure in which the water vaporizes. The…

The bathtub ring can be seen for miles. The 120-foot-high band of rock, bleached nearly white by mineral-rich water, circles the shoreline of Lake Mead. Water levels have dropped by almost 100 feet in the past decade, and the ring has emerged as a stark reminder of the drought enveloping the American Southwest. It also represents a looming crisis for the largest drinking-water reservoir in the U.S., one that has prompted the most ambitious water-construction project in recent history. Right now, 600 feet beneath the lake's glassy blue surface, a massive custom-built tunnel-boring machine—almost as long as two football fields and heavier than four 747s—is plowing inch by tedious inch through wet, fractured bedrock. Spanning nearly 24 feet in diameter, its rock-gnawing face is alive with the movement of 44…

About 750,000 people in the U.S. end up with diarrhea each year from drinking water contaminated by the Cryptosporidium parasite. In part, that's because Crypto is resistant to the chlorine that water-treatment plants use to kill other microbes. Dozens of cities around the world are now installing massive ultraviolet-light arrays to zap the germ. As water flows through treatment facilities on its way to the tap, it passes through pipes specially outfitted with UV lamps. The UV light penetrates Crypto's thick protein shell, damaging the pathogen's DNA and rendering it harmless.…

Scientists know more about the surface of the moon and Mars than they do about our own seafloor. Which helps explain the grand vision of the French architect Jacques Rougerie, who's designed an ocean-going laboratory that rivals the Starship Enterprise in scope. Rougerie envisions his machine, the SeaOrbiter, as a sort of space-age buoy floating unobtrusively in the ocean, equipped with submersibles and a team of divers who can explore and analyze the marine environment. “If we want to better understand the ocean, we need a paradigm shift in research,” he says. That means direct observation in remote locations like the Sargasso Sea, where forests of seaweed create a unique and poorly understood ecosystem. “Eels from North America and Europe converge here to spawn after spending decades in freshwater rivers,”…

On a windless day on the west shore of Oahu, Hawaii, I strapped a pair of propellers to my legs, walked into the surf, and disappeared beneath the surface. Without a single kick, I was racing over the sand, cutting through the water at an Olympic pace. It felt more like flying than swimming. I struck a Superman pose and sailed into the abyss. Designed for Special Forces divers, the Patriot3 Jetboots are unique among personal propulsion devices because they're hands-free and provide sea-creature-like agility. The two propellers, which hang from a waist harness and attach at the thigh, can send divers to nearly four knots. A lithium-ion battery worn at the small of the back could last up to four hours. With the Jetboots—sort of a misnomer given how…

For every human on the planet—and there's more than seven billion of us—43 pounds of electronic waste is generated each year. The United Nations predicts that by 2017, the figure will climb by as much as 30 percent. A lot of the refuse ends up in China, where locals burn it to extract precious metals. In the process, they inhale some of the most toxic chemicals in existence. According to researchers at Oregon State University, villagers living close to these e-waste dumps are 1.6 times more likely to develop cancer than urban dwellers who live in cities so polluted that particulates routinely block out the sun. John Rogers, a materials scientist at the University of Illinois at Urbana-Champaign, has created ribbons of silicon so thin—just 35 nanometers thick—that they can…

Jose Salvador Alvarenga was fishing off the coast of Mexico in late 2012 when a powerful storm sent his boat adrift. Marshall Islanders found the battered vessel nearly 16 months later, stuck on a reef—with Alvarenga still alive inside. Rainwater and a diet of fish and turtle sustained him (or so he told the press). Curious how DIY savvy could stave off disaster, we asked Frances and Michael Howorth, authors of The Sea Survival Manual, for advice. Don't discard any clothing; multiple layers can keep you warm during cold nights. On hot days, drape or prop clothes overhead. Never drink seawater. If you have a raincoat, detach the hood and use it to catch and store rainwater. Plastic bags and rain boots also make excellent containers. Always rinse them with…

Mastering robots in the company of professors doesn't require a classroom. Or even pants. EdX, a remote-learning site run by Harvard and MIT, offers dozens of free online courses, including one called Autonomous Mobile Robots. We audited a class to see what it entailed. Here's how you, too, might pick up the skills to program bots that can navigate and map a room. Instructors from the Swiss Federal Institute of Technology in Zurich walked us through key concepts in a series of web videos, including robotic locomotion and obstacle detection. After each lecture, the instructors assigned a problem set covering the material and encouraged any overachievers to try additional exercises. The additional exercises involved a downloadable simulator, which allowed us to control a virtual robot named Bob. We coded in…

When Popular Science published this cover story in July 1963, the average diver could survive for about 10 minutes at 200 feet underwater. Engineer Edwin A. Link wanted to change that: “The problem I am interested in is how to stay at great depths long enough to do something useful,” such as marine salvage, he told Popular Science. His Deep Diver vessel was the first to dispatch and retrieve divers beneath the surface, by way of a pressurized compartment. It launched in 1966 and had a maximum depth of 1,350 feet. Engineers continue to develop innovative ways to accommodate long-term ocean observation. One example: the SeaOrbiter, which is designed with pressurized living quarters to allow prolonged diving expeditions. For more, turn to page 50. 100 FEETThe U.S. Navy's first operational…

On December 7, 1972, an astronaut aboard Apollo 17 snapped the first fully illuminated photograph of Earth from space. The Blue Marble Shot, as it came to be known, is one of the most widely published photos ever taken. Environmentalists used it to galvanize their burgeoning movement, and it has graced millions of T-shirts and Earth Day flags since. Though not the first portrait taken from space (that was in 1946), the Blue Marble touched us most deeply. It told the story of our world—vibrant, complex, and alone—and it showed unambiguously that ours is a planet of water, so far the only one known. As a molecule, water is polar, meaning it holds a slight charge across its axis. Because of that quality, the particulars of which are singular in…

Q: WHAT'S YOUR FAVORITE WATER-RELATED ACTIVITY? I load the tub with water balloons and let the kids play, which gives me time to take a break! Having it tested for lead content. Filling up the kiddie pool for my dog. I use the sprayer on the kitchen faucet as a water gun. Swimming! Carbonating it to maximum saturation. Sitting in the surf when the waves are small, so you can feel the ocean brush right over. Washing dishes. It's like a calming Zen ritual. As a kid, I would run the hose down my slide to make a waterslide. It was worth the bruises. When it's frozen and I'm on a ski slope.…

A Little More Detail: Most smart-home devices require separate apps to control each of them. The AllSeen Alliance, a consortium of product manufacturers, wants a common code instead. It promotes AllJoyn, a framework that companies can employ to create devices that share data and capabilities with one another. The code allows control of all devices through a single interface. For example, if a connected smoke alarm is triggered, it would send an alert signal through any televisions, computers, and speakers on the network.…

1With help from Waste Services of the Bluegrass, Toyota developed a method to convert gas released by landfills into electricity to power its Kentucky plant. When the system goes live in 2015, it will generate enough energy to run about 800 homes. 2Swedish supercar maker Koenigsegg is using 3-D—printed parts to optimize its multimillion-dollar Agera One:1. The printed titanium exhaust end piece, for example, is now a single unit that's one pound lighter than the prior version. 3Later this year, Ferrari, Honda, and Mercedes will be among the first automakers to roll out Apple's CarPlay in-dash system. CarPlay integrates iPhone apps—messages, music, and maps—into a car's display and incorporates Siri voice control. 4In April, Audi launched a unique car-sharing pilot program in Berlin. Customers can switch among three different models…

In February, Facebook purchased the WhatsApp messaging service for the mind-boggling sum of $19 billion. It was the largest acquisition of a venture-backed company ever, but it also proved a clear, albeit subtle, point: Our relationship to personal data is shifting. WhatsApp charges users $0.99 a year, a fee it justifies in a straightforward way—no ads, no data mining, no kidding. Now that one of the world's most prolific data miners owns WhatsApp, we'll see if the service can continue to guard privacy in the same way. Regardless, the lesson stands. People are realizing just how much their data is worth. Paying for privacy used to be common. Any letter sent via the U.S. Postal Service comes with an implicit security guarantee: Opening someone else's mail can be a federal…

An MIT team has turned a multi-million-dollar NASA contract into the most advanced rethink to date of the classic passenger jet. The design, nicknamed the Double Bubble, calls for an extra-wide fuselage and rear-mounted turbofan engines. The configuration would allow the craft to burn 70 percent less fuel than a Boeing 737 while producing significantly less noise and nitrogen oxide, a pollutant that causes acid rain. So when can we board? NASA says it would like to see the 180-seat craft airborne by 2035, when air traffic is projected to double. Engineers will push toward that goal this summer, when they subject a scale model to a second round of wind-tunnel tests at Langley Research Center. Here's a look at some of the fuel-saving features they will scrutinize. Fuselage: At…

John McCormick, a 63-year-old cab driver, was on his porch the morning of July 26, 1978, when he was robbed and shot dead. His wife, awakened by the commotion, reported that she saw the assailant flee wearing a face stocking, which investigators later found near the scene. Police identified 17-year-old Santae Tribble as the prime suspect after an informant linked him to the gun. At Tribble's trial, an FBI agent testified that one of the hairs found in the stocking “matched in all microscopic characteristics” to Tribble. While half a dozen witnesses corroborated Tribble's alibi, the hair was enough to convince the jury. Tribble served 23 years before he was paroled in 2003. Nine years later, mitochondrial DNA testing on the same hair samples revealed that Tribble was no match…

Maintaining a perfect cellular water balance is crucial for our bodies to function as they should. That's the job of tiny proteins known as aquaporins, which channel water across cell membranes. Recently, scientists discovered that aquaporins are present in tumors and may accelerate the growth of certain cancers. Researchers have also discovered that Devic's disease, an incurable autoimmune disorder that can lead to paralysis, is caused by antibodies that attack aquaporins. Multiple labs are targeting aquaporins as they work to develop new treatments for disease. For cancer, that means identifying a molecule that can block aquaporins in tumor cells. It's a difficult challenge. “Water always finds a way in,” says Dr. Alan Verkman, professor of medicine and physiology at the University of California at San Francisco. The leading inhibitors are…

At first glance, the bright red shipping container that sits by the side of the road in a slum outside Johannesburg doesn't look like something that could transform hundreds of lives. Two sliding doors open to reveal a small shop counter, behind which sit rows of canned food, toilet paper, cooking oil, and first-aid supplies. Solar panels on the roof power wireless Internet and a television, for the occasional soccer game. And two faucets dispense free purified drinking water to anyone who wants it. Created primarily by Coca-Cola and Deka Research and Development, the New Hampshire company founded by inventor Dean Kamen, the container is meant to be a kind of “downtown in a box”: a web-connected bodega-cum-community center that can be dropped into underdeveloped villages all over the world.…

Data Visualization byPITCH INTERACTIVE As the climate shifts, rivers will both flood and dry up more often, according to the latest report from the Intergovernmental Panel on Climate Change. Shortages are especially likely in parts of the world already strapped for water, so political scientists expect feuds will become even more intense. To track disputes worldwide, researchers at Oregon State University spent a decade building a comprehensive database of international exchanges—both conflicts and alliances—over shared water resources. They found that countries often begin disputes belligerently but ultimately reach peaceful agreements. Says Aaron Wolf, the geographer who leads the project, “For me the really interesting part is how even Arabs and Israelis, Indians and Pakistanis, are able to resolve their differences and find a solution.” NERD BOX The map displays nearly…

A primeval predator patrols the dark, icy waters of Antarctica's Ross Sea, antifreeze proteins coursing through its blood. An icon of the Southern Ocean, the Antarctic toothfish is a crucial link in the rich food web of the planet's most pristine marine ecosystem. Since 1996, it has also become prized by fisheries, which call its meat “white gold.” In the 2011–12 season, 15 ships from six nations pulled roughly 3,500 metric tons of Antarctic toothfish from the Ross Sea. (Eight nations have vessels registered to fish there.) More than half the catch ends up in the U.S., where it's sold (along with Patagonian toothfish) as the more palatably named Chilean sea bass for upwards of $25 a pound. Toothfish grow only about one centimeter per year, so scientists fear the…

The recipe for creating a habitable planet turns out to be surprisingly simple: Just add water—and atmospheric gases. Mars has both, relics from four billion years ago when the planet was warm and wet. “When it comes to Mars, and only Mars, the notion of terraforming is no longer in the realm of science fiction,” says NASA astrobiologist Chris McKay. Humans could warm the planet and restore a thick atmosphere in a matter of decades, but producing breathable levels of oxygen would take 100,000 years with today's best technology: plants. New inventions could, in theory, speed that along too. “Living off the land is going to be essential for long-term human explorers beyond Earth,” says Laurie Leshin, a geochemist on the Mars Curiosity team. “We have to figure out how…

Videogames may seem like the last place for fruitful work in biotechnology, but Stanford University bioengineer Ingmar Riedel-Kruse has reinvented 1980s classics to enlist living microbes. His custom electronics and augmented-reality software coax microorganisms to play key roles in Pac-Man, Brick Breaker, and other reimagined 8-bit titles. Here's a look at how Riedel-Kruse's rig works. 1 MICRO-AVATAR Riedel-Kruse uses single-celled protozoans called paramecia that typically live in ponds. Changes in an electrical field can cause some species to alter their steering (a behavior called galvanotaxis). The microbes selected for the videogames swim toward electricity using cilia that cover their bodies. 2 REMOTE-CONTROL MICROBES A shallow, thumbnail-size chamber with a glass bottom corrals the paramecia. Electrodes lining the chamber's edges are wired to a controller with an omnidirectional button. Pushing it…

Short answer Yes, but you'd be asking for trouble. “In terms of strength, wood is pretty good,” says Mike Gruntman, professor of astronautics at the University of Southern California. Early airplanes were built with wood, all the way into the early 1930s. (There were also wooden submarines.) Gruntman thinks it may be possible to build a wooden spacecraft that could survive the stress of a rocket launch. Once your timber ship made it into space, however, you'd have a lot of problems. For starters, the organic matter would contain a fair amount of water. In a vacuum, that water would leak out and evaporate, which could affect the structure—especially in places where screws and brackets were attached. Even if this process unfolded over many weeks or months, the integrity of…

Living in Hawaii, Brian Lam spends a lot of time in the water: diving, sailing, swimming, surfing. The activities, Lam says, bring him closer to the environment he loves. But none compare to the experience of testing a military-grade personal propulsion system for us this month (page 55). “I could easily touch any turtle or keep up with schools of small fish,” he says. “It was the closest I've felt to real belonging.” The more out-of-left-field a project is, the more likely it will grab contributing editor Gregory Mone's attention. “It almost disappoints me when I find out the project is somehow related to [its creator's] job,” he says. This month, after coming across a web video, Mone tracked down a Canadian father who (much to the chagrin of his…

For 16 years, EyeSee360 has made panoramic cameras for the military and other industries. Now the company has adapted its technology for the 360Fly, a consumer video camera that allows anyone to record a whole scene—360 degrees around and 240 vertically—without moving. Users mount the baseball-size camera on a tripod or GoPro-style on a helmet or surfboard. The lens captures the image, and the camera sends footage to a phone or computer over Wi-Fi. Viewers can watch the video as a single framed shot or click-and-drag to see the entire scene almost as if they were there. Horizontal field 360 degrees Vertical field 240 degrees Approximate resolution 1.5K Weight 4.2 ounces Price $450 (est.)…

An Xbox One or PlayStation 4 has nothing on a gaming PC. Towers pack so much video memory and such powerful graphics chips that they can render details meticulous enough (smoke, shadows, sunlight) to make a console choke. But with power comes problems. PCs can be large, hot, and loud—not exactly what you want in the living room. For that, look to Steam Machines, a new breed of computer that delivers PC gaming from the body of a console. The boxes run the new SteamOS, an interface that makes browsing and buying games as simple as picking a movie on Netflix. (It's a couch-potato version of Steam's desktop remote game-delivery service.) Then there's the hardware: Even the smallest Steam Machine has a top-shelf laptop graphics chip that, while powerful, runs…

At the 2010 World Cup, Adidas debuted the Jabulani, the tournament's official game ball. It flopped. Players lamented its tendency to break unpredictably in the air—a consequence of its smooth stitching (see “The Physics of Flying Objects,” above right). With this summer's Cup to prepare for, Adidas didn't want to repeat its mistake. The company tested the new Brazuca with more than 600 players over the course of three years. Although the ball has fewer panels than its predecessor—six versus eight—its seams are three times deeper, giving it less drag, which helps ensure it'll fly where a player wants. The amount of drag an object experiences determines how it will fly through the air; the less outside forces it interacts with, the truer it will fly. As air passes over…

In March, amid escalating tensions in the Ukraine, the Russian Soyuz rocket blasted NASA astronaut Steven Swanson and two cosmonauts to the International Space Station from a launchpad in Kazakhstan (pictured here). The flight was part of NASA's $424 million contract extension with the Russian Federal Space Agency, which covers Soyuz flights through 2017. Yet as diplomatic relations between the U.S. and Russia deteriorate, so too does the security of our only ride to space. It didn't help when NASA announced in April that it was suspending most missions with the Russian space agency (except for operations involving the International Space Station). Former NASA astronaut Tom Jones is cautiously optimistic, though. “My feeling is there won't be any change to the space-station operation,” he says, “but the announcement will antagonize…

As chief mechanical officer at the Mt. Rainier Scenic Railroad in Mineral, Washington, Stathi Pappas managed to parlay an obsession into his dream job. He oversees a fleet of six steam trains, the largest operational collection in North America, plus two vintage diesel-electrics. We asked him what it takes to keep them chugging. Popular Science:You were trained in industrial archaeology. How did that lead to this job? Stathi Pappas: Just like archaeologists who study the Mayan world or the classical world, an industrial archaeologist studies the industrial world. I was writing my dissertation on society and steam locomotives when I had one of those aha moments. I thought, Wouldn't it be interesting if I could actually live in the past? So I got a job at another tourist railroad; then…

In 2007, when my daughter was seven years old, we would brush our teeth together every night as part of our daily ritual. To conserve water, we would turn off the faucet after wetting our brushes and turn it back on only to rinse. One night, I didn't turn off the water fast enough to her liking. She turned off the faucet, made an angry face at me, and growled, “Turn off the water, Daddy. The scientists need time.” That statement still resonates with me today, not only because of her precociousness but also because she was exactly right. Kids seem to intuitively get this: We need to conserve our resources to buy ourselves time so scientists can find new solutions to our problems. And this is especially true for…

data visualization byKATIE PEEK In the 1970s, several studies turned up pharmaceuticals in treated U.S. sewage water, and drugs have been a known unknown in water supplies ever since. Recently, researchers at the Environmental Protection Agency tested 50 U.S. wastewater-treatment plants serving more than 46 million people for 58 common drugs. They found many of the meds, but thankfully at concentrations so low it would take years to drink a full dose. NERD BOX Circles represent the maximum detected concentrations of each drug. Lowest is norfluoxetine at 15 parts per trillion; highest is Diovan at 5,300 ppt. Treated wastewater is not consumed directly, so typical exposures would be even lower. *THE STUDY TESTED FOR GENERIC COMPOUNDS, BUT SOME BRAND NAMES ARE LISTED HERE FOR EASIER IDENTIFICATION.…

ONE The user places a hose in any dirty water source—say, a polluted river or well—and a small pump draws the fluid into a boiling chamber. As the water reaches roughly 100°C, it turns to steam, which leaves behind any pollutants. They flow out of the chamber via a separate hose. TWO The steam rises into a compressor, which squeezes it and thereby raises its pressure and its temperature by about 10°C more. The high-pressure vapor now has a higher boiling point, which means it can condense back into water at a temperature greater than 100°C. THREE A counterflow heat exchanger runs the superheated water past the incoming flow of dirty water. The process heats the incoming water and cools the hot water to room temperature. That distilled water is…

Seventy percent of the Earth's surface is liquid—yet water scarcity affects more than a billion people each year. Since the 1970s, the gold standard for desalination has been reverse osmosis, in which big pumps push seawater through membranes that allow water molecules to pass through but not salt. The process is effective—it removes 99 percent of the salt—but it's costly and energy-intensive. Put another way, today's desalination technology exacerbates climate change and worsens the water crisis it's meant to solve. By leveraging electricity rather than force, Kyle Knust, a 26-year-old doctoral student in analytical chemistry at the University of Texas at Austin, created an energy-efficient way to separate salt from saltwater with an electric current. His device is called the Waterchip (it's small enough to fit in the palm of…

Within policy circles, people often bandy about the term “water-energy nexus.” Like most wonk-speak, it's a rather complex way to express a simple relationship. Energy production requires a tremendous amount of water, almost on par with irrigated agriculture. And water production needs a lot of energy, for pumping, treating, and transportation. They're interdependent. And therein lies the problem. We asked the U.S. Department of Energy's Michael Knotek, the deputy under secretary for science and energy and a scientist himself, how to plan for a future in which we'll demand a lot of both. Why worry about the water-energy nexus anyway? If you look around the world, the water-energy nexus is the first thing foreign governments talk about, particularly in developing countries. Over the next 40 years, we're going to have…

Marc De Repentigny was only trying to be responsible when he built an 80-pound, seven-foot-tall motorized Transformers suit. Married with kids, he decided to audition for a French-Canadian game show that offered a chance at prize money to the most unusual contestants. De Repentigny molded styrene plastic into armored paneling, made motorized LED eyes, and spent months perfecting realistic-looking thrusters. A servomotor in the thrusters triggers a puff of compressed air and a flashing LED light, making the robot appear ready to blast off. His arms slip into the robot's wide shoulders, and his hands reach into the bot's elbows, where buttons let him activate the motorized fingers and faceplate. The suit doesn't transform into a jet, but it did get De Repentigny on the game show—where he won $128,500.…

Don't let NASA monopolize planetary exploration. Build a robot that ambles around a familiar yet alien landscape: your backyard. It won't avoid obstacles, but this rover is a fun introduction to solar-powered electronics. MATERIALS: INSTRUCTIONS: See detailed instructions and a full list of materials at popsci.com/simplerover Soldering iron Approximate time to build this project Cost: About $50 Difficulty: 2 out of 5 hearts Two gear motors Two solar panels Assorted LEGO pieces Cyanoacrylate glue Use the LEGOs to build a chassis of your design that supports four wheels 2 inches or larger in diameter. Glue the LEGOs together for extra durability, and attach the front wheels to the hardened chassis. Mount one rear wheel to each gear motor, then secure the motors to the rear of the LEGO chassis. Solder…

Short answer Not if we get creative. A“There's a lot of hype around this issue,” says Upmanu Lall, professor of earth and environmental engineering at Columbia University and director of its Water Center. But, he says, we're in little danger of running out of water overall. One could conceive of a scenario in which we've used up all the freshwater locked in ice or aquifers. Indeed, the water table has already dropped at an alarming rate in specific regions. (We're on pace to deplete the Ogallala Aquifer, which underlies much of the Great Plains, in the coming decades, for example.) But even if that happened, we'd still have access to other forms of water. “The most common resource is rainfall, and that's renewable,” Lall explains. “It's nature's way of treating…