Table of contents for January 2013 in Popular Science

50The Helmet WarsAmericans suffer 3.8 million sports-related concussions each year. Can we build a better device to protect the brain?By Tom Foster 32The Year in ScienceThe big stories to watch for in 2013, plus a look back at last year's highlights. 44China's Secret ArsenalInside the Chinese military buildup.By Peter W. Singer 04 From the Editor 05 Peer Review 06 Megapixels: An explosion on the sun 73 FYI: Can antiperspirant make you hotter? 84 The Future Then What's New 09 Skis for any slope 10 The Goods: A quiet keyboard, and more 12 Ford's practical plug-in hybrid 14 Slimmer speakers with ferrofluid 16 Tools that clean up after themselves 17 A disaster-proof hard drive 18 The death of channel-surfing Headlines 21 Why large predators are invading cities 24 The crime-solving bullet…

On August 31, 2012, more than one billion tons of plasma exploded from the sun's surface and began speeding toward Earth at approximately three million mph. Unlike a solar flare, which is a burst of extreme radiation, a coronal mass ejection (CME) is an eruption of million-degree electrified gas. Because the sun spins faster at its equator than at its poles, its magnetic fields twist to the point of breaking as often as three times a day. When they reconnect, the energy involved pushes plasma clouds into space. A camera aboard NASA's Solar Dynamics Observatory satellite captured this 200,000-foot filament right before it detached; a 304-angstrom-wavelength filter enabled scientists to see the plasma. Three days later, the CME produced a benign effect: auroras over the Northern Hemisphere.…

At the beginning of the space program, one big problem facing NASA engineers was finding a way to move rocket fuel into engines in space with no gravity to guide the flow. They developed an additive called ferrofluid, a liquid infused with magnetite particles that they could manipulate with a magnetic field. Companies now use the substance to control parts in everything from racecar suspensions to hard drives. This year, designers at Sony found a new use for it: building slim speakers that produce louder, clearer sound than any others their size. Designers replaced a key speaker component, the damper, with a microns-thin ring of ferrofluid. Speakers generate sound waves when a magnet moves a voice coil back and forth to push against a diaphragm; the damper ensures that the…

In normal conditions, a hard drive is the most affordable and efficient way to back up music, video, and photo libraries. Yet most drives—typically made from lightweight materials such as plastic—won't last through a disaster. The ioSafe N2 will. Designers wrapped the system's dual hard drives in materials that protect it against the worst. By default, the dual hard drives mirror each other, so if one drive fails, the other will have a copy of every byte lost. (This of course cuts the max storage from eight terabytes to four.) In the event of a complete meltdown, ioSafe will pay for forensic data recovery. A 0.05-inch steel shell surrounds the entire N2 and protects the drive from falls. The shell also helps deter thieves; an accessory allows users to padlock…

Sherlock Holmes could look at a gun shell and know exactly what went down. The firearm? The shooter's stance? The culprit? All revealed with a glance. In the real world, using a shell to solve a crime is a painstaking, and often unsuccessful, process. Investigators may be able to match a bullet with a gun type, but that doesn't necessarily lead to the person who shot it. Useful fingerprints are rare, and the heat of firing a weapon can destroy DNA evidence. A team of nanomaterials scientists led by Paul Sermon, of Brunel University in England, has developed a bullet that captures the DNA of anyone who touches it—and leaves a tracer on the person, too. 1 Scientists dipped a bullet in a formaldehyde-urea resin, creating a microscopic scratchy surface…

LAST JANUARY, the Swedish BitTorrent tracker Pirate Bay quietly introduced a new category, called Physibles, to its inventory. “We believe that things like three-dimensional printers, scanners, and such are just the first step,” one of the site's managers wrote at the time. “We believe that in the nearby future you will print your spare parts for your vehicles. You will download your sneakers within 20 years.” That's probably an understatement. MakerBot's $2,199 Replicator 2, which prints small objects from drips of melted bioplastic filament, is generating headlines today. But far sharper home stereolithographic printers, which selectively cure liquid photopolymer resins with lasers, are on the way; Formlabs is set to begin delivery on its $2,299 Form 1 in February. And that's just the start. The next generation of consumer 3-D…

THE warning from climate scientists has been clear and consistent for decades: Man-made greenhouse-gas emissions, which increase every year, are causing the planet to warm, and that will have dire consequences—the specifics of which (timing, intensity, location) aren't completely understood right now. Unfortunately, the steadiness of that message is also its undoing in the media; more often, the rare scientific dissenter gets the limelight. “Because it's been pretty much the same for 25 years, it almost never gets reported,” says Gavin Schmidt, a climate modeler at NASA Goddard Institute for Space Studies. Two statements of scientific consensus forthcoming in 2013 will provide an opportunity to set the record straight: the National Climate Assessment, which lays out observed and anticipated trends in the U.S., and the Fifth Assessment Report from the…

ON April 5, 2012, President Barack Obama sat at a small, wooden desk in the White House Rose Garden and signed the JOBS Act, one of the most transformative pieces of securities legislation written since the Great Depression. Among the 22 pages of dense legalese, one section stood out: the Crowdfund Act. Pending the creation of SEC regulations later this year, new businesses will be able to make their own IPOs, and small investors could act as venture capitalists. Start-ups and inventors raised an estimated $2.8 billion on crowdfunding platforms such as Kickstarter in 2012, a 529 percent increase from 2009. But they could only solicit donations, presales of products, and loans. By allowing equity investment, lawmakers expect to supercharge crowdfunding, which would make nascent businesses less reliant on angel…

Hurricane Sandy slams U.S. With 140 terajoules, more than twice the energy of the atomic bomb dropped on Hiroshima Biofuel takes flight With 100% unblended fuel derived from Brassica carinata, a plant in the mustard family Physicists confirm Standard Model (maybe) 800,000,000,000,000 Number of proton collisions generated to find Higgs boson-like subatomic particle Felix Baumgartner dives from stratosphere Time: 9 minutes 9 seconds Distance: 24.3 miles Max Speed: 833.9 mph James Cameron dives to Mariana Trench Time: 2 hours 36 minutes Distance: 6.8 miles Max Speed: 4.7 mph First private spacecraft docks with ISS “Houston, station. Looks like we got us a Dragon by the tail.” —Astronaut Don Pettit, on the arrival of SpaceX's Dragon capsule Heredity may not be limited to DNA Six other types of sugars can form…

In 2011, the PLA began testing the J-20, China's first homegrown stealth fighter, which could enter service sometime after 2017. Analysts believe the J-20 has radar-deflecting skin and internal weapons bays. Very little public information about China's combat aircraft development program exists, but the emergence this past September of a second stealth fighter prototype—the J-31 Falcon Eagle, which some observers think could be capable of performing takeoffs and landings on aircraft carriers—suggests that the J-20 is only the first in a series of advanced Chinese fighters.…

The official NFL helmet partner since 1989, Riddell launched the 360 in 2011. It has extra padding around the front and sides of the head, and the company's signature Concussion Reducing Technology, which adds even more padding. Yet for all that foam, most experts say it does little to address rotational forces, the primary cause of concussions. Made by the nine-year-old helmet company Xenith, the X2 replaces foam padding with an array of air-filled cylinders that compress upon impact by releasing air through tiny holes. The harder the hit, the stiffer the response. Such adaptive cushioning can protect against both lower-level and higher-level forces but still does little to address rotation. Made with thermoplastic urethane cushioning that performs consistently even in extreme weather, the Ion 4D, Schutt says, “is designed…

AFTER THEIR LANDLORD sold her house, Tristan Chambers and Libby Reinish found themselves scrambling for a new home. They agreed then to never again endure the insecurity of leased living. It was 2010, “a time when we didn't know where we were going, but we still wanted to have roots,” Chambers says. Unable to afford a conventional brick-and-mortar house, they spent roughly a month's rent to build what they call the Whittled-Down Caravan: an Oregon Trail-style mobile abode made mostly of salvaged parts. Chambers and Reinish, who were living in Santa Fe, New Mexico, at the time, had no clue how to construct a mobile home. So they spent two months learning woodworking, wiring, and other essential skills from the Internet. A three-month build kicked off with little more than…

Artist and cycling enthusiast Gregory de Gouveia, based in Chico, California, has built bike sculptures before. But his 12-foot-tall clock called Time to Change—a fusion of more than a dozen two-wheeled machines—is his largest and most functional aesthetic contribution to the sport. The project began when another local artist asked de Gouveia if he wanted to create a sculpture for the 2011 Chico Wildflower Century Ride. De Gouveia decided to build an unofficial clock for the bike event. He called on nearby cycling communities to donate used bikes, and once enough junkers rolled into his shop, he held a “disassembly party” to remove their gears, frames, chains, and other components. De Gouveia pieced together the gigantic clock's skeleton from the scrap metal in roughly three weeks, and then spent another…

Q: Why don't spiders get trapped in their own webs? Hairy feet and oily legs. Orb-weavers, arachnids that capture their prey using sticky webs, make up more than one fourth of all known spiders. These species spin their creations with spiral crossbeams dotted with drops of viscous goo. (The webs' radial and framing threads are left clean.) When an insect brushes against these drops—each thread can carry several dozen per millimeter—it gets stuck, and the spider rushes over to inject it with venom or cocoon it in silk. The question, of course, is how does the predator escape its own glue traps? Naturalists have only recently worked out the mechanics of the sticky web—and of avoiding it. “It's surprising how little attention the topic has gotten despite how many people…

IBELIEVE 2013 will be a grand year. Big things are coming. First of all, astronomers expect a cloud of gas roughly three times the mass of Earth to begin falling into a supermassive black hole in September. It's not just going to be amazing (blasts of x-rays and radio waves!), it will be the first time such a thing happens within range of human instrumentation, which means we get to watch. This is also the first year we expect private spaceflight to begin delivering payloads into orbit at the regularly scheduled intervals with which we move big things around here on Earth. Also, the post-Higgs era begins this year. Like I say, lots to look forward to. But what will make 2013 truly grand is not the big, cosmic stuff.…

Until now, there hasn't been an all-mountain ski that rides well in any conditions. Skis must be either sturdy and narrow to chop through icy snow or flexible and wide to glide across powder. The core of a ski determines its weight and strength, and thus the conditions it's best suited for. Engineers at Wagner Custom have created a core that's strong yet light, and the first skis to incorporate it, the 2–4 Ultralights, are fit for just about any mountain. To create a core 40 percent lighter and 30 percent stronger than traditional hardwood, Wagner engineers pressure-soak soft, light East Coast timber in a epoxy resin derived from paper mill waste. When hardened, the resin turns the wood into a plasticized block. A double helix of carbon fiber woven…

No matter which side the hexagonal Unmonday speaker sits on, its ceramic housing will dampen vibrations. Based on how the speaker is positioned, an accelerometer tells it to act as part of a mono, stereo, or surround setup. $890 (import) Inspired by acoustic guitars, the Koostik passive amplifier quadruples an iPhone's speaker volume. Two hemispherical sound chambers concentrate audio much like a megaphone before sound waves exit through front-facing holes. $95 The Comet produces sound that's 57 percent less distorted than that of a traditional wood speaker. Designers embedded the two drivers in a solid block of stone, a substance that won't absorb sound waves. $1,400 (pair)…

TWENTY YEARS ago, Bruce Springsteen lamented “57 channels, and nothin' on.” Today, 57 channels would be a relief: Between cable, broadcast, and Web services, we have tens of thousands of individual programs to choose from, and no good way to figure out what to watch. In the early days of the Internet, surfers were just as confounded. Then search engines arrived and made it easy to find information. A similar change is now occurring in television—and it promises to deliver viewers from painstaking channel surfing to perfectly tailored programming. Right now, viewers have plenty of help sorting though individual catalogs. Netflix, for instance, uses an algorithm that translates viewers' ratings into suggestions, which are reportedly accurate within half a star 75 percent of the time. Comcast is also starting to…

As of November, when this issue went to press, 2012 was on track to become the warmest year in the U.S. since 1895, when national record keeping began. From January through October, the 4,451 U.S. weather stations that have been tracking temperatures for at least 30 years measured nearly 28,000 high-temperature records but only 5,200 lows. That's the largest ratio of high to low records ever. “There is a lot of natural variability in these numbers,” says Claudia Tebaldi, a senior scientist at the independent research organization Climate Central. “But it's definitely behavior that has the imprint of a warming climate.” Scientists say this trend will continue. An Intergovernmental Panel on Climate Change report published last year predicted that the kind of heat records that fall once every 20 years…

ON July 4, 2012, a panel of scientists at the Large Hadron Collider in Geneva announced the discovery of a new particle, the long-anticipated Higgs boson (or something very much like it). The Higgs is the final piece of the Standard Model of particle physics, a theory that accounts for everything we experience in our lives, from rocks to puppies to stars and planets. After decades of searching and billions of dollars, the Higgs discovery marked the end of one era and the beginning of another, which scientists will embark upon in 2013. If the previous era was about understanding the physics of everyday stuff, the next will be dominated by the attempt to grasp more elusive realms, including one of the most mysterious of all: dark matter. Astronomers have…

EARTH'S two most populous nations have major space launches slated for 2013: China will send a lander to the moon and India will propel an orbiter toward Mars. On the surface, their goals appear similar—cement a toehold in a frontier dominated by the U.S., Russia, and Europe—but the ways in which they will achieve them are very different. China wants to do everything that other nations have done in space, and more, including building its own space station and mounting a lunar sample-return mission. And it has a methodical road map to reach those targets. The planned Chang'e 3 lunar probe will serve as a testbed for launch and landing techniques, as well as cameras, samplers, and other instruments. “China is beyond doing things in space for show,” says Gregory…

IN 2009, the annual Pwn2Own cybersecurity competition provided hackers with a shot at cracking smartphones. They failed. In September, the event offered phones as targets again. This time, contestants seized control of them, successfully exploiting vulnerabilities in the two most popular operating systems, iOS and Android. For the most part, smartphones have escaped the viruses and botnets that have plagued desktop computers for decades. That luck may not hold out in 2013. The learning curves of cybersecurity professionals and cybercriminals track pretty closely. If the good guys have hacked iOS and Android, the bad guys will quickly follow. The first mobile malware attempted familiar invasions, stealing contact information and pictures from devices. But cybersecurity professionals expect a range of unconventional hacks as well. In the last couple of years, researchers…

IN A SINGLE GENERATION, China has transformed itself from a largely agrarian country into a global manufacturing and trading powerhouse. China's economy is 20 times bigger than it was two decades ago and is on track to surpass the United States' as the world's largest. But perhaps most startling has been the growth of China's ambitious and increasingly powerful military. Just 10 years ago, the budget for the People's Liberation Army (PLA) was roughly $20 billion. Today, that number is more like $100 billion. (Some analysts think it's closer to $160 billion.) The PLA's budget is only a sixth of what the U.S. devotes to defense annually, but defense dollars go much further in China, and in the years ahead, Chinese military spending will grow at the same rate as…

With a space station under construction and plans for a manned moon mission, China aims to alter the balance of power in orbit. In 2007, the nation showed off its antisatellite missiles by shooting down a decommissioned weather satellite, creating 40,000 shards of space junk in the process. Now it's testing an unmanned orbital vehicle known as Shenlong, or Divine Dragon. Comparable to the U.S. Air Force's X-37B space plane, the Shenlong could rapidly place satellites in orbit—and potentially carry weapons that could disable the communications, navigation, and surveillance satellites of adversaries.…

THE SYSTEM The Multidirectional Impact Protection System (MIPS) reduces the rotational forces that cause concussions. In a MIPS-equipped helmet, a thin layer of molded plastic fits atop a player's head, beneath the padding and hard polycarbonate shell. Rubber straps affix the MIPS layer to the helmet. HOW IT WORKS MIPS mimics the human head's own protective system, in which a layer of slippery cerebrospinal fluid sits between the brain and the skull. When an impact occurs, the skull can rotate just a bit relative to the brain. With MIPS, the rubber straps allow the helmet to move just a bit relative to the sliding, low-friction head cap, thereby eliminating much of the twisting motion before it reaches the brain. THE RESULTS In lab tests, MIPS reduces brain rotation by as…

TIME 3 MONTHS COST $1,500 A motorcycle battery stores energy gathered by a 50-watt solar panel on the caravan's roof. A modified plug-in car inverter transforms the battery's DC output into AC, and a charge controller conditions power for common electronics. Chambers and Reinish say their system collects enough juice to run three devices—e.g., LED lights, a portable fan, and a laptop—for at least three hours. Borrowing the travel-light tricks of pioneers, such as rounded caravan walls, helped the couple trim their home's weight and cost. Corrugated steel gave structural support without the heft of wood planks, and waterproof canvas made for a suitable ceiling. They also skipped insulation, built a mattress out of straw, and dual-purposed couch cushions as dirty laundry sacks. A sink in the caravan drains through…

We've all failed to eject a USB drive before unplugging it, prompting warnings—but not absolute truths—about lost data. Knowing the mechanics of three common storage devices could save you precious time, 1s, and 0s. Traditional hard drives can store terabytes of data on spinning, magnetized disks. Unplugging a hard drive, however, can cause data-reading components to suddenly crash into them. Damage is rare but severe, ranging from permanent errors to a dead drive. Better safe than sorry. Always click Eject. Solid-state drives, or SSDs, lack the moving parts and whirring sounds of hard drives. They're more yank-friendly—with two caveats: SSDs can't be transferring data or running TRIM, a command that “trims” away deleted data to boost speed. Sudden removal can fry tiny components, so eject SSDs, too. As for pinkie-size…

Q: Can too much antiperspirant cause me to overheat? Used only under the arms? No. Sweating is how the body cools down. As water evaporates off the skin, due to a difference in vapor pressure, it draws heat away from the body. So if we stopper our sweat glands with metallic salts (the active ingredient in most antiperspirants), decreasing the amount of sweat our bodies can release, will that leave us overheated? Would that in turn prompt our brains to compensate by signaling our glands to sweat more in untreated areas? Would a vicious circle of perspiration begin? No. According to Craig Crandall, a specialist in thermoregulation at the University of Texas Southwestern Medical Center, the places where we tend to put our antiperspirant aren't particularly important for keeping us…

Everything that Andrea Rossi says or does screams “scam!” The criteria for proving cold fusion should include a reactor that makes dozens or hundreds of watts for days or weeks without fresh fuel, with an output-power-to-input-power ratio of 3:1. Everything should be tested independent of the inventor. None of this has ever been done for Rossi's machine. maryyugovia popsci.com Dear Mr. Steve Featherstone, I read the article in Popular Science. It is nice and honest. Wonderful photos. Warm Regards,Andrea Rossi…

Plug-in cars save gas and cut pollution, but at a cost. The Nissan Leaf has a maximum driving range of about 75 miles. The Chevrolet Volt seats just four people. And at nearly $40,000 apiece, neither is cheap. The Ford C-Max Energi plug-in hybrid, by contrast, seats five and combines gas power and a grid-charged lithium-ion battery to reach the EPA-certified equivalent of 108 mpg. It goes 620 miles on a full gas tank and battery. And at $29,995 (after tax credits), it is by far the most affordable plug-in on the market. It's the kind of car that could, just maybe, take automotive electrification mainstream. The C-Max Energi combines a pair of electric motors and a 2.0-liter four-cylinder Atkinson-cycle gasoline engine (the same ultraefficient design used in the Toyota…

A rotary hammer, which simultaneously turns and punches a drill bit, is the ideal tool for drilling holes into brick and concrete. But making those holes also creates a huge, powdery mess. Snap-on HEPA vacuums developed by tool manufacturers can now trap dust right at the source. Pulverized concrete contains silica, a known carcinogen. In the past, DIYers had to tether their tools to freestanding shop vacs to keep the dust contained. They can now attach a compact vacuum directly to the tool. Suction from the vacuum pulls debris through a nozzle near the tip of the bit, into aluminum tubing, and directly into a canister. The only cleanup required is dumping the waste.…

IT'S BEEN a while since he tried to count them all, but Stan Gehrt estimates that more than 2,000 coyotes make a comfortable living in the Chicago metropolitan area today. And in the 12 years he's spent tracking the animals with radio and GPS collars, Gehrt, a wildlife ecologist at Ohio State University, has witnessed some remarkable adaptations. Suburban coyotes, like the pack in a residential area a few miles from O'Hare airport, have learned to live in much smaller territories than they do in rural places. Downtown coyotes, which roam among the towers and traffic of the Chicago Loop, thrive in the city by hunting enough small rodents to feed themselves and their young. Some urban coyotes have even been spotted crossing streets in busy traffic—at the light, looking…

“In the future, tiny vehicles might travel through your body to image your insides, take samples, and deliver drugs. At Stanford University, my colleague Anatoly Yakovlev and I built a prototype of such a device. It's about the size of Abraham Lincoln's head on a penny. We power and control the prototype wirelessly by sending radio waves to its two-by-two-millimeter antenna from about two inches away. No battery is required, which is key to miniaturization. Mechanical propulsion is inefficient at this scale. Instead, we use magnetohydrodynamic propulsion, which takes advantage of the fact that an external magnetic field can push an object by creating a Lorentz force on its electrical circuitry. We operate the device near a magnet—we imagine the patient lying on a magnetic table—and use radio waves to…

DURING 2012, two scientific teams announced, in separate studies, that they had transformed ordinary adult skin cells into neural cells, a breakthrough that could change the course of human stem cell research. Stem cells hold enormous potential for medicine because they can develop from undifferentiated cells into a variety of specialized ones. But their use has been stymied by ethical concerns; most are harvested from human embryos, which are destroyed in the process. In 2006, Shinya Yamanaka of Japan's Kyoto University figured out a way to bypass embryonic cells: He generated stem cells from skin cells, a discovery for which he shared the 2012 Nobel Prize in medicine. But his method was slow and inefficient. The new techniques—pioneered by Marius Wernig of Stanford and Bronwen Connor of the University of…

NATURAL gas has emerged as a cheap, abundant fuel source because of hydraulic fracturing, and energy companies are now racing to develop it. Gas isn't perfect. Its environmental reputation is controversial at best; emissions from methane that escapes during drilling give it a big carbon footprint. But natural gas releases 50 percent less carbon dioxide than coal at the smokestack, so proponents have championed its use as a bridge to still-cleaner sources of power. Recent trends seem to support that idea. Coal use is plummeting—it now generates just 42 percent of U.S. electricity—and carbon emissions from energy production have dropped to the lowest level in 20 years (the recession deserves credit for that too). Meanwhile, wind generation jumped 10 percent in 2012, and solar more than doubled. But for gas…

WITH his second term secured, President Barack Obama can now turn his full attention to advancing the priorities that will help define his legacy. On the stump, Obama championed science and technology. Under his administration, those fields, particularly renewable energy and medical research, should continue to enjoy significant federal support over the next four years. John Holdren, Obama's science and technology adviser, told Popular Science: “We are committed to continuing our focus on ensuring that science, technology, innovation, and education have the support they deserve in order to fuel America's economy, prepare the tech-savvy workforce and science-savvy citizenry of tomorrow, and meet the manifold challenges of health and biomedicine, energy, environment, and national security.” Although the lion's share of federal research dollars still goes to defense—56 percent in fiscal year…

In 2006, China unveiled an unmanned aerial vehicle (UAV) design known as Dark Sword, which has since vanished from the public eye. Western analysts aren't sure whether the craft is still under development. If it is, certain design characteristics—such as a suspected ramjet engine—suggest that it's a high-speed drone that could carry out surveillance and strikes far from Chinese shores. Whatever the Dark Sword's fate, China's UAV plans are ambitious: This past summer, the Chinese government announced plans to build 11 coastal drone bases.…

On August 19, 2012, in week two of the NFL preseason, Indianapolis Colts wide receiver Austin Collie ran 17 yards out from the line of scrimmage, cut right toward the center of the field, caught a pass, and was immediately tackled by Pittsburgh Steelers cornerback Ike Taylor. As Taylor came in for the hit, his helmet appeared to glance off the left side of Collie's helmet. Then the cornerback wrapped his arm around Collie's neck and jerked the receiver's head to the right. An instant later, Steelers linebacker Larry Foote came barreling in from the opposite side and slammed his elbow into the right side of Collie's helmet. As the receiver fell to the ground, his helmet first hit Foote's knee and then struck the ground face-first. Collie sat up,…

For decades, the term “punch-drunk” has been used to describe boxers left permanently loopy after a career of fighting. The clinical name for the condition is chronic traumatic encephalopathy (CTE), and it can happen to any athlete who suffers frequent blows to the head. CTE has no known treatment, and doctors can only diagnose it postmortem, by physically examining the brain for symptoms. Scientists at the Center for the Study of Traumatic Encephalopathy at Boston University examine the brains of dead contact-sports athletes. In its first year of operation, 17 of the 18 brains researchers tested had CTE. Also, a team of scientists recently reported that former NFL players are three times more likely than the general population to die from brain diseases such as Alzheimer's. At its most basic,…

TIME 3 hours for circuit, 20 minutes for surgery COST $50 for parts [or $100 for kit] DIFFICULTY 4 circles If cockroaches send you scrambling, use neuroscience to reverse the human-insect power balance. Carefully electrifying the nerves in a roach's antennae makes the insect think it has met an obstacle—a sensation that can be manipulated to steer it. The trick could turn roaches into handy tools. Alper Bozkurt, an engineer at North Carolina State University, envisions a network of cyborg roaches assisting in search and rescue. Neuroscientists Greg Gage and Tim Marzullo, meanwhile, think hacking insects could inspire kids to research and improve electronic interfaces with the human nervous system. Gage and Marzullo developed a $100 RoboRoach kit that includes all the tech required for insect neurosurgery. But you can…

Early in his engineering career, Rohit de Sa faced a painful reality: endless scrolling through lengthy computer documents. Just an hour of flicking a mouse's wheel was enough to cause carpal-tunnel-like symptoms in his wrist. So de Sa repurposed an old VCR, computer mouse, and camera lens caps to build an ergonomic jog wheel. With your own box of junk and some effort, you can re-create de Sa's retro spinner. TIME 5 hours COST About $10 DIFFICULTY 3 out of 5 cirles Disassemble a VCR and pull out its polished, drumlike head. Strip all wiring and gut the electronics. Harvest a mouse's computer chip, oscillator (typically a two-pronged cylinder), and USB cable. Bend the mouse chip's pins to fit into a two-millimeter-pitch veroboard. Solder surface mount capacitors between the chip's…

When two Grumman F4F-3 “Wildcat” fighters appeared on Popular Science's cover in February 1941, the U.S. had not yet joined World War II, but the possibility of an attack on American soil loomed large. Writer Carl Dreher estimated the likelihood of an air bombing on a U.S. city by analyzing foreign aerial strength. He said that mainland cities were secure, but coastal cities were in danger of hit-and-run raids. At the time, military aircraft could not fly directly from Asia or Europe to the U.S. (though Dreher predicted that “such bombers will be an aeronautical commonplace in five years”). Instead, planes would take off from a nearby land base or aircraft carrier—which they did 10 months later when Japan attacked Pearl Harbor, prompting the U.S. to declare war. The world's…