Popular Science - New Technology, Science News, The Future Now

This Newer, Stronger 3-D Printed Gun Costs Just $25

Clay Dillow — Wed, 22 May 2013 17:15:00 GMT

A Wisconsin engineer has produced a cheaper, more durable version of Defense Distributed's 3-D printed pistol on an inexpensive, consumer-grade printer.

Defense Distributed’s plastic, 3-D printed “Liberator” single-shot handgun was here for a moment and then it was gone in more than one sense. For one, the news cycle turned over. Moreover, the State Department came down on Defense Distributed asking it to pull the CAD file for the Liberator off its servers until the lawyers could figure out if putting a free, downloadable CAD file up on the Web violated any arms export regulations. But the Liberator is back and--presumably to Defense Distributed co-founder Cody Wilson’s glee--it is evolving.

By the time the State Department asked Defense Distributed to pull down the CAD file for the Liberator, it was already replicating across the Web. And one of the people who appears to have gotten his hands on it is a Wisconsin engineer who identified himself to Forbes only as “Joe.” Joe has printed what he adorably calls the “Lulz Liberator” on a $1,725 Lulzbot A0-101 consumer-grade 3-D printer--a printer that is far less expensive than the industrial-grade one used by Wilson and company to create the original Liberator, which essentially was a disposable pistol--one shot and the barrel breaks, requiring the user to print another.

Joe’s Lulz Liberator--cost: $25--successfully fires eight rounds through a single barrel (and a ninth round through a replacement barrel) in the video below, proving that plastic guns have already leapt beyond the one-shot-per-print limitation. The Lulz Liberator is still a single-shot weapon--that is, it only holds a single round at a time--but it can be reloaded and fired multiple times using a single barrel.

Joe made his Lulz Liberator from PA-747 ABS plastic, a standard kind of ABS that is the working material for most consumer-grade 3-D printers. Yet he claims that it’s stronger than the more expensive stuff Wilson prints with in his larger, more costly Stratasys printer. Joe also augmented his version with a few components not found on the original Liberator, which is all plastic except for the firing pin made from a standard nail. The Lulz Liberator uses a metal nail for a firing pin, but also employs metal screws--available for pennies at your local hardware store--to hold the body of the firearm together rather than relying on plastic pins as Wilson's does. And like Wilson’s, it contains a non-functioning piece of steel designed to bring it into alignment with the Undetectable Firearms Act.

The Lulz Liberator reportedly misfired several times during tests, and some of the screws and firing pins had to be replaced throughout the testing. Reloading is also no simple matter; each spent .380 cartridge expanded enough that they had to be pounded free of the chamber with a hammer. So it’s not like the Lulz Liberator is a rapid-fire, or even a semi-rapid fire plastic firearm.

What it is: A confirmation that Wilson’s Liberator design indeed functions the way he says it does, as well as proof that now that this thing is out there in the maker ecosystem it’s going to evolve independent of Wilson and Defense Distributed.

One key difference between Wilson’s Liberator and Joe’s Lulz Liberator: the Lulz Liberator design file is not available for download online and it’s unclear if or when Joe might release it into the wild. But it doesn’t really matter. Defense Distributed’s file is still circulating out there, and it’s unlikely Joe is the only maker out there tinkering with new ways to make better firearms from cheap plastic.

[Forbes]

Super-Real Mario Kart

Gregory Mone — Wed, 15 May 2013 14:03:07 GMT

A pack of hacked go-karts that re-creates a classic videogame.

One summer, a young engineer walked into Austin’s Park, an amusement center outside the Texas capital, and introduced himself to the manager as an intern from Waterloo Labs—a hacking collaborative sponsored by the engineering juggernaut National Instruments. He and his colleagues wanted to convert the go-kart track into a real-life, crash-happy version of the classic videogame series Mario Kart. The manager didn’t just agree. He lent him a kart.

In Super Mario Kart, cartoon drivers zoom around a track littered with interactive objects. Some boost a player’s speed, others hijack steering, and many can be launched at competitors. Four interns at Waterloo Labs grew up playing the game, so when someone suggested making a real-world version, they couldn’t resist. “We weren’t entirely sure how we were going to do it,” says intern Tim Lynch, “but we said, ‘Okay, we need to do this.’ ”

Re-creating the game’s interactivity meant that objects on the track had to communicate with speeding go-karts. At first, the team thought of using passive, close-range radio-frequency identification (RFID) tags. The interns tested that idea by tossing their ID cards at a security scanner to see whether the embedded chips transmitted a signal fast enough. “That didn’t work,” says Humphrey Huang. Next, they tried an active, self-powered RFID system. It cost an extra $500 but could transmit signals as far as 30 feet away, allowing each kart to interact with objects via its own RFID reader.

The interns’ biggest hurdle: overriding the kart’s controls. “We needed to be able to fight against someone trying to turn the wheel,” says Lynch. They eventually selected powerful pneumatic pistons, which they attached to the chassis using zip ties, duct tape, and braces. When a driver captured or collided with an item, a reader would send that item’s unique ID to the computer, which, in turn, ordered pistons, valves, or servomotors to swerve, stop, or speed up the kart [see “How It Works,” next page].

They tested the hacked kart in the park’s garage, tossing plush toys embedded with RFID tags at the vehicle and watching it respond like a living creature. Then—with the track manager’s approval—they modified three other racers and added pneumatic cannons so that drivers could fire kart-crippling toys at competitors.

On game day, Huang, Lynch, Dylan Caswell, and Peter Gaylor raced, crashed, and futilely tried to prevent their carts from careening into the railing when RFID-tagged toys took over the controls. Lynch learned to steer with his knees while grabbing objects from the track and loading them into his cannon. Huang shot a plush turtle shell across the track at Caswell, triggering the RFID system in his kart and jamming the brakes. “We were doing lap after lap and thinking, ‘It’s actually working,’ ” says Lynch. “ ‘We’re actually playing Mario Kart.’ ”

“LET’S-A-GO!”

The red shell slows down a driver and jams steering. Air pistons attached to the front wheel’s tie rods lock it in place, while another piston depresses the brake pedal.

A driver who captures a green shell can stuff it into an air cannon and then launch it toward an opponent to fully stop his kart.

Plastic bananas cause one tie-rod piston to contract and another to expand, forcing the front wheels to the right on the left-aiming track. “We figured that would be most perilous,” says Hunter Smith, Waterloo Labs’ internship coordinator.

Normally, a spring prevents the throttle lever from opening more than 85 percent. The RFID tag in the plush mushroom, however, triggers a servomotor to pull on the lever—enabling the driver to reach speeds nearing 35 mph.

The lucky driver who grabs a plush star temporarily earns a fully opened throttle, while his Wi-Fi–equipped controller orders all other karts to brake.

(Get the specifics of the project on the next page)

brightcove.createExperiences();

HOW IT WORKS

Hacking go-karts into the racecars of the Mario Kart videogame series was no simple feat. Four interns from Waterloo Labs began with standard four-stroke-engine vehicles and added components such as ruggedized cRIO computer controllers, Wi-Fi routers, and RFID readers.

1) TOY CANNON
Compressed air fed into a PVC pipe can blast a plush toy at competitors as far as 30 feet away.

2) FASTENERS
Zip ties, brackets, and other removable hardware made all modifications reversible.

3) AIR TANKS
A 3,000psi paintball tank stores 48 cubic inches of air to charge add-on pistons.

4) ELECTRONICS
A suite of gadgets can detect the RFID codes of objects on the track and then control the kart.

5) STEERING
A 130psi air piston attached to each tie rod can steer a kart off-course.

6) BRAKE OVERRIDE
A valve can depress the brake pedal by directing high-pressure air into a piston.

Time: 8 weeks
Cost: $1,200

WARNING: We review all our projects before publishing them, but ultimately your safety is your responsibility. Always wear protective gear, take proper safety precautions, and follow all laws and regulations.

This article originally appeared in the May 2013 issue of Popular Science. See the rest of the magazine here.

Gene Machine

Tue, 14 May 2013 20:57:21 GMT

A pipe that copies DNA using the heat of a lightbulb.

Biology’s equivalent of an office copier is a PCR machine. PCR, short for polymerase chain reaction, is now a staple in crime-scene forensics, heredity tests, and organism hijacking. It’s a mind-boggling feat. Among billions of base pairs that make up DNA’s genetic code, PCR finds exact sequences and, in a couple of hours, makes billions of copies—enough to decode or splice together useful combinations of genes. Professional machines cost about $10,000 dollars each, but Russell Durrett has devised one from PVC pipes, a 150-watt lightbulb, a computer fan, a cheap microcontroller, and a few reagents he ordered online.

1) PILE UP
Stack five pieces of PVC piping to form a silo [right] that holds vials of DNA, heats them with a lightbulb, and cools them with a computer fan.

Top: Drill a dozen or so ¼-inch holes into the top of a slanted adapter (to hold the vials), fit a pipe inside the adapter’s base, and cut a square hole in the exposed pipe to match a computer fan’s exhaust port.

Middle: Cut the same square port in the top of a straight PVC coupling and hot-glue the fan in place. Drill a hole into the coupling’s side, just above the center, and bolt on a clamped lightbulb socket.

Bottom: Drill a hole in a second coupling for a bundle of wires leading to an Arduino Uno microcontroller.

2) WIRE UP
Connect the socket and computer fan to 5-volt relays, and link them to the Arduino. Lead one socket wire to a 110-volt AC power source, and wire a thermistor to the Arduino. Insert the thermistor into a vial containing mineral oil and water, and place it in a vial hole. This gives the Arduino temperature data, allowing it to turn the lightbulb—and heat—on and off.

3) PICK A GENE
Whether you’re testing breakfast cereal for genetically modified grains or screening yourself for HIV resistance, pick a gene to copy. You’ll need to order from the Internet reagents that can hijack DNA-copying molecules [see “How It Works,” on the next page.]

brightcove.createExperiences();

HOW IT WORKS
PCR machines cycle temperature to enable DNA-copying reagents, including primers, nucleotides, and the enzyme Taq polymerase.

201ºF
DNA temporarily unzips into two strands.

131°F
Primers—small pieces of DNA that “prime” replication—attach to the ends of a gene.

162°F
Taq polymerase recognizes the primers, latches on, and copies DNA between them.

. . . And Repeat
In the first five minutes, PCR makes two copies of a gene. Subsequent 30-second cycles continue the doubling. By the eighth cycle, 256 genetic copies exist, and by the 30th—
a couple of hours later—there are more than a billion.

Time: 5 hours
Cost: $50
Difficulty: 3/5

For Durrett's complete build instructions, download this PDF. Arduino code is available here.

This article originally appeared in the May 2013 issue of Popular Science. See the rest of the magazine here.

Father's Day Gift Guide [SPONSORED POST]

Mon, 13 May 2013 20:45:00 GMT

It’s that time of year again when we express our appreciation for dear old dad. If your father is like most, he can be difficult to shop for. But don't panic, DEWALT has your back with some great gift ideas that will make the most fastidious father jump for joy.

Whether your dad is a licensed contractor or just likes to work on that old ’66 Chevrolet Camaro, DEWALT’s Father’s Day lineup will equip him with the most professional tools on the block.

Pear Head Ratchet(s)
Drive Socket Set(s)
Every self-respecting man needs a good ratchet and socket set. They’re ideal for removing or tightening bolts and nuts and are great for automotive repairs, appliance installation, and furniture assembly. Maybe mom wants a new pergola built for the backyard, well the best tool for the job would be a new ratchet and socket set. Instead of just using a nail or a screw, tell dad to fasten the crossbeams with heavy gauge nuts and bolts with his new Pear Head Ratchet and that pergola will have the added strength to last for years.

The Pear Head Ratchet from DEWALT comes in three convenient sizes to meet dad’s needs (1/4”, 3/8”, 1/2”). And the socket sets are available in 23 or 25 piece sets with a ratchet and convenient socket rail to help keep that drawer organized.

The whole lineup comes with a lifetime warranty, a chrome vanadium steel construction that adds strength & durability which offers a three times longer life than a typical ratchet, contoured, ergonomically designed handle with anti-slip grooves for comfort & control and a low profile directional lever for one-hand operation.

So, if you’re dad has a drawer full of sockets but his ratchet has seen it’s better days, grab him a one of DEWALT’s Pear Head Ratchets or if he’s in need of a whole new set grab him one of the Drive Socket Sets.

10 pc. Combination Wrench Set(s)
Along with a hammer and screwdriver, a wrench set is the backbone of every great tool kit. The 10 piece Combination Wrench Set from DEWALT comes in either MM or SAE and is incredibly versatile. Each wrench features an anti-slip design that locks the wrench onto the fastener and helps prevent slippage for 400% more gripping power.

10 pc. Reversible Ratcheting Wrench Set(s)
So, your dad already has a wrench set? Then kick things up a notch this year and get him one of DEWALT’s 10 pc. Reversible Ratcheting Wrench Sets. Each 10 pc. Reversible Ratcheting Wrench Set comes in either MM or SAE. The ratcheting end reduces time spent reaching for those hard to reach nuts and bolts by creating continuous contact and the anti-slip design offers 400% more gripping power than a typical ratcheting wrench that helps reduce fastener damage and provides tons of torque.

Mechanics Tool Set(s)
There is nothing more frustrating for dad than being right in the middle of a project and not having the right tool for the job. But with one of DEWALT’s Mechanics Tool Sets he will never have that problem again. The Mechanics Tool Sets come in three sizes to meet any father’s needs: 118 piece, 156 piece, and 204 piece. It’s great for simple tasks like replacing a spark plug and fixing a flat tire or for more complicated projects like rebuilding an engine block.

Each set comes with crossed rings on the sockets to help reduce slipping, deep laser etched markings to help identify socket sizes easy, a ratchet with 5° arc swing and slim head design for maneuverability in constricted areas as well as a 72-tooth gear system for high torque ratcheting and much more.

So whether dad is a bit of a gear head or if he just needs a great tool set for projects around the house one of DEWALT’s Mechanics Tools Sets will definitely fill the bill.

Available only at Sears and sears.com these new tools are backed with a no-hassle lifetime warranty.

How To Turn A Barf Bag Into A Phone Mount

Thu, 09 May 2013 19:23:37 GMT

Become the envy of fellow passengers on TV-free airplanes

On the streets of Manila, Flynn Jason Siy entertains himself with urban gymnastics. On airplanes, he avenges boredom with barf bags. During a budget flight to the resort island of Boracay—on a plane lacking TVs—Siy made a cradle for his smartphone from the metal closure tabs of several bags, allowing him to comfortably watch movies on the device. Here’s how to engineer your own seat-back screen in a few minutes.

1
Take three barf bags from nearby seat pockets, and remove their pliable closure tabs.

2
Bend two tabs into Z shapes. Work one end of each tab into gaps above the tray table lock. The other ends cradle the bottom of your phone.

3
Fashion the third tab into an inverted J, and wedge it between the lock and the upholstered seat to secure the top of the phone.

4
Plug in your headphones, sit back, relax, and (actually) enjoy the flight.

2 DIY Printers That Would've Impressed Gutenberg

Thu, 09 May 2013 19:23:23 GMT

Inventive ink!

Now : Bioprinter
If office printers can build images by spraying tiny blobs of ink onto paper, why couldn’t they also print in living cells? The question compelled Patrik D’haeseleer and a few collaborators at Biocurious, a biohackerspace in Sunnyvale, California, to build a machine that prints patterns of bacteria engineered to glow green. The team first altered a Hewlett-Packard 5150 printer but met two complications: The ink cartridges used filters and nozzles too fine to allow bacteria through, and the device’s single range of motion thwarted printing directly onto gelatinous petri dishes. So they started over, beginning with an Arduino-controlled printing device called the InkShield—a gadget with inkjet nozzles large enough to accommodate E. coli. Next, they built a two-axis printing platform out of old CD drives. They filled the cartridge with bacteria engineered to glow in the presence of arabinose (a sugar E. coli likes to eat) and printed the microbes on petri dishes laced with arabinose. Soon, living luminescent words appeared. D’haeseleer is now replacing the nozzles on the machine with a syringe pump that can print in gels as well as liquid solutions. He says he hopes to use it to lay down 3-D biological structures on the fly—perhaps even an artificial leaf that performs photosynthesis.

Then : Clothes Wringer Etching Press
In 1939, Popular Science published instructions for building an etching press out of an old clothes wringer. With the addition of a 35-cent scribing tool (about $5.79 today) and a few easy modifications to the clothes wringer, aspiring printmakers could etch patterns onto paper and even silk. It was a great way to bring a design to life—though not quite as literally as today.

Amp Your Ride

Thu, 09 May 2013 15:00:00 GMT

Charge electronics on the go with a bike-mounted USB hub.

I’m a mechanical engineer who loves bicycling. When gas prices soared through the roof in 2009, I rode my bike to save money. I wanted to charge USB devices, such as my phone, during commutes but didn’t want to spend $150 (or more) on a commercial wheel-hub generator. In the end, I was able to build a cheaper system.

Electrical work wasn’t my expertise, so I had to teach myself how to build circuits from the ground up. I’m now on version three of my two-port USB generator, which is about 70 percent efficient above 12 mph and creates less drag on bike wheels than other designs. With the right equipment, you can build one yourself.

STEPPER MOTOR
A stepper motor converts the rear wheel’s spinning motion into electricity. To keep the flow consistent enough to charge devices, get a five-volt, 3.3-amp model (about $10 at electronics surplus stores). Attach a small wheel—I cut one from plywood—to the stepper motor. Line the small wheel’s rim with foam padding and electrical tape to give it grip. When mounted against the bike’s rear rim, the small wheel will turn the motor.

RECTIFIER
USB devices use direct current, but stepping motors provide alternating current. Convert the flow by building a rectifier out of eight 1N4001 diodes ($1 a pair at hobby stores). Link the diodes in anode-to-cathode pairs, and solder them together to make four pairs. Solder two pairs side by side into a bridge, and repeat with the other pairs for a total of two bridges. Connect each bridge’s midpoints with four-conductor wire to the stepper motor’s positive and negative wires [see wiring diagram above].

USB CAR CHARGER
Open a two-port USB car charger. Remove the spring on the cylindrical end (positive lead) and the two clips (negative lead) that normally secure the charger in a power port. Solder the rectifier’s positive and negative leads to corresponding terminals on the charger. Connect the other ends of the wires to the matching terminals on the stepper motor.

GENERATOR FRAME
Build a frame to keep the generator’s small wheel in contact with a bike rim. My bike has a rear rack, so I cut a six-inch-long slab of aluminum to span two bars of the rack [see above photo]. I secured the slab under the generator with U-bolts. Next, I cut two 90-degree aluminum angles for the other side of the generator and bolted them to the slab to clamp everything in place. Attach the USB charging port wherever you’d like (I put mine below the seat), and start pedaling for portable power.

Time: 1 day
Cost: $25
Difficulty: 3/5

For Costlow's complete build instructions, download this PDF.

This article originally appeared in the May 2013 issue of Popular Science. See the rest of the magazine here.

Dear Schools: Stop Treating Science-Curious Kids Like Criminals

Dave Mosher — Tue, 07 May 2013 20:15:00 GMT

We shouldn't punish students who are trying to understand how their world works.

On April 22, Kiera Wilmot, a 16-year-old public school student in Bartow, Florida did what any kid with an ounce of curiosity does: She performed an experiment. Like many acts of science, however, it didn’t go as planned.

Wilmot allegedly mixed a few household chemicals in an eight-ounce water bottle, capped the lid, set it down, and stood back to watch, according to local news reports. She expected a little smoke to appear. Instead the top blew off and made a firecracker-like bang.

No one was hurt. No property was damaged. She didn’t even run away. The principal’s eyewitness account, along with those of Wilmot’s friends and schoolmates, all suggest she was simply satisfying her curiosity on school property before classes began. "She wanted to see what would happen [when the chemicals mixed] and was shocked by what it did," Bartow High School principal Ron Pritchard told 9news.com.

Despite praising Wilmot as a "good kid" who has "never been in trouble before," Polk County Public Schools trumpeted its zero-tolerance policies and called the police. They arrested Wilmot and charged her with two felonies. Now expelled, Wilmot may be forced to finish her education in a juvenile facility and graduate with a permanent record.

A big part of the problem here is fear. Schools have allowed it to guide student codes of conduct that ignore what science is, how it works, and the importance of experimentation in inspiring influential researchers. I'm specifically reminded of a piece called "Don't Try This At Home" by Steve Silberman, who reported on the increasing criminalization of garage chemistry.

The story ran seven years ago this month but is still surprisingly relevant. Silberman explores how and why chemistry kits and education became so toothless. As part of his reporting, he highlights prodigious scientists who owe their success to foolish childhood experimentation. Gordon Moore, who pioneered the integrated circuit and co-founded Intel, for example, created and detonated his own dynamite at age 11. David Packard, co-founder of Hewlett-Packard and father of Silicon Valley, proudly manufactured gunpowder as a kid. (Thomas Edison should have been in there, too -- he performed enough dangerous feats to fill his biographies.)

Other brainiacs regale us on the importance of backyard chemistry in leading to fruitful science careers, including neurologist Oliver Sacks, Don "Mr. Wizard" Herbert, Popular Science's own Theodore Gray, and Roald Hoffmann, winner of the 1981 Nobel Prize in chemistry. "There’s no question that stinks and bangs and crystals and colors are what drew kids ... to science," says Hoffmann in Silberman’s story. "Now the potential for stinks and bangs has been legislated out."

Silberman convincingly argues that fear of lawsuits (by manufacturers and teachers alike) have led U.S. educators to shy away from teaching science that poses any degree of danger. Schools have codified those fears in zero-tolerance policies that reject context and reason in delivering punishment. Suddenly, a popping soda bottle that hurts no one becomes a life-threatening explosive device.

Did Wilmot make a mistake? Yes. Should she carry two felonious charges into her adult life? No.

Kids are kids. Their futures ride on trying, failing, and learning from mistakes. Much of that happens during personal experimentation, and schools should equip them to do it responsibly, whether or not it happens on school property.

Sure, dangerous behaviors deserve punishment. But it's time we stop creating and acting on zero-tolerance school policies to dole them out. We need to treat kids as kids and give them a fair shake by weighing context, reason, and maturity -- not brand them as criminals when they create "stinks and bangs," either accidentally or intentionally, for experimentation's sake.

High Schoolers Build DIY Sensor-Activated Locker For Wheelchair-Bound Classmate

Francie Diep — Mon, 06 May 2013 18:24:46 GMT

It pops open at the wave of a hand.

A couple high school seniors in Michigan recently rigged a junior's locker to open with the wave of a hand, the Livingston Daily reported. It's not a mean trick: The redesign helps Nick Torrance, a Pinckney Community High School junior who has muscular dystrophy, open and close his own locker.

Torrance has a sensor attached to the right arm of his wheelchair, and he waves his hand over that to work his locker. He likes the opener, he told the Livingston Daily. He otherwise has a fellow student assigned to carry his books, jacket and put things away in his locker.

The idea for the opener came from his occupational therapist, Amy Uphouse, who initially thought you had to be able to buy a locker-opening device somewhere. She couldn't find one, however, so she asked the school's robotics teacher, Sean Hickman, if other students could make one. Hickman recruited seniors Micah Stuhldreher and Wyatt Smrcka, who won first place in the SkillsUSA national robotics competition last year and are competing again this year.

Like in any device development, it took a lot of trial and error for Stuhldreher and Smrcka to make something that would work for their target audience. For example, they initially built a locker-opening button, but Torrance wasn't strong enough to push it, so they replaced it with a sensor.

Torrance didn't comment much in the Livingston Daily article, nor at all in the accompanying video. He is shy, the newspaper reported. That's understandable. So the paper talked to his mom, Jean Torrance, too. But did they have to include this line? "He wants to talk to girls; he’s at that age," the Livingston Daily quotes her as saying about her 18-year-old son. 1) We're not sure what this has to do with the sensor-activated locker. 2) Mom, that's such an embarrassing thing to say!

[Livingston Daily]

This Real-Life Videogame Health Bar Tracks Your Virtual Demise

Colin Lecher — Mon, 29 Apr 2013 19:30:03 GMT

Things just got real.

Reddit user bfayer spent more than 100 hours creating this: a test-tube-like, Arduino-based liquid container that's a real-life representation of videogame health. Whenever bfayer is injured in a game, the colorful tube adjusts the amount of water inside, trickling down until... game over.

A fish tank pump automatically removes some of the water when the system, hooked into the game's software, picks up on an in-game injury, and this video makes it all seem pretty darn accurate: the water in the tube is uncannily close to the amount of health shown on screen, and the water level falls almost simultaneously with the virtual health bar. It's pretty, too.

Finally a reason for gamers to be happy about having a game kick the crap out of them.

[Reddit via Kotaku]

The Chemistry of Nitrous-Powered, Pot-Infused Liquor

Paul Adams — Wed, 17 Apr 2013 15:00:00 GMT

How one New York bartender fused alcohol and marijuana forever

Behind the bars of some of the nation's finest cocktail joints, there are secrets: secret recipes, secret bottles for friends only. One of these is the Green Dragon, a liquor potently infused with marijuana.

There've been alcohol-based tinctures of cannabis before, of course -- usually seen in turbid brown jars on windowsills, But one prominent New York bartender (I'll call him Jon) has been responsible for bringing the infusion up to date with modern, artisanal cocktail culture. Jon is a serious, technologically minded craftsman of beverages; he works as a cocktail consultant, and has designed the cocktail programs of more than one Manhattan bar.

He's refined a method that's quick, gives precise, predictable results, and reportedly maximizes the delicious herbal flavor of the drug, to provide a civilized sippable for the beverage connoisseur. Jon's nitrous-powered Green Dragon "just tastes good. We've dialed the strength back substantially, not because we can't make it stronger, but just because people want to be able to drink more of it, because they like it so much."

Jon can rattle off the exact date when (friend of PopSci) Dave Arnold published on his blog the "game-changing" nitrous infusion technique, a method for rapidly forcing new flavors into liquor using gas pressure inside a whipped-cream charger. And it was not very long at all after that date when Jon first had the notion to apply the technique to cannabis.

"If you don't want to smoke, you're left with edibles, but with edibles, there's no way to dose it. Someone hands you this thing, and you're like: who made it? how was it made? You eat a half or a quarter of it, and you wait and wait, and you either feel nothing, or you're destroyed."

“We've dialed the strength back substantially, not because we can't make it stronger, but just because people want to be able to drink more of it.” But alcohol absorbs through the digestive tract in a faster, much more predictable way than solid edibles--and so does whatever's dissolved in that alcohol. Hence the precision-infused Green Dragon.

The rapid infusion works--the theory goes--because high pressure forces N2O and alcohol deep into the plant material. Then, when the gas pressure is suddenly released, it causes the nitrous oxide to come out of solution and violently bubble around the bits of plant material, agitating the mixture on a microscopic level.

Traditional infusion in alcohol takes days or weeks, and extracts a broader spectrum of compounds from the plant -- not just the more volatile molecules responsible for psychoactive effects and bright, pleasant flavors, but ones that dissolve over time and impart murky flavor and what some call a headachy effect.

"Ten years ago, I had gotten my hands on this ungodly amount of hash. We couldn't smoke it all. So we started putting it into neutral grain spirit, and it dissolved in, but the thing was, we couldn't get as high. So we gave up and forgot about it for a week, and meanwhile it sat in the car in the 120° sun for a week. The next time, we took a couple of drops and it destroyed us."

"What happened? THC [the main active ingredient in cannabis] normally has a carboxyl group that's attached to it. In order for it to fit into the lock-and-key mechanism of our bodies' cannabinoid receptors, you have to break off the carboxyl group. That takes 30 years--or heat."

The carboxyl group starts breaking off as the temperature gets higher, so Jon heats his Dragon as part of the infusing process. Toasting the cannabis before infusing can drive off some of the delicate aromatics, giving it a cooked flavor, and also runs the risk of vaporizing the THC itself. So Jon heats his only to 100°C (212°F), which gives the infusion a delicate flavor and just the strength he wants, no more.

"You can dial in the recipe to know exactly how many grams you're getting per serving."

The effect of the drug should remain steady for about four hours. One to one-and-a-half ounces is what Jon considers a single serving; six ounces is his maximum imaginable dose.

Nitrous Green Dragon

Here's how Jon does it:

a one-liter heat-tolerant whipped-cream whipper
two nitrous oxide chargers
a double boiler large enough to accommodate the whipper bottle
750 ml mezcal at room temperature (Jon uses Vida or Sombra)
3.5 grams (1/8 ounce) of cannabis (Jon uses "indoor high-grade sativa")

Roughly break up the cannabis.
Put the cannabis and the mezcal in the whipper bottle.
Close the canister and charge it with two charges of N2O according to the instructions.
Let it sit for 5 minutes.
Vent out the pressurized gas. NOTE: you are venting aerosolized ethanol with THC dissolved in it, as well as laughing gas. Jon says "Probably nobody would want to inhale this."
Stir the liquid and let it sit until the gas boils off.
Place the sealed canister in a double boiler and let it simmer for an hour.
Strain the solids out of the liquid and discard them or dry them for other uses. The liquid is nitrous green dragon.

Jon developed his recipe using mezcal, whose smokiness complements the herbal flavor of the drug. And mezcal has another advantage -- its innate low pH keeps the color of the infusion vivid green, while more alkaline liquors let it become dingier. (See photo: mezcal, gin.) But other bartenders have perfected their own preferred recipes. A New Orleans bartender uses cognac; one in Seattle makes it with gin to which he adds a little green Chartreuse, and creates a heady variation on the Last Word cocktail (equal parts gin, green Chartreuse, maraschino liqueur, and lime juice) called the Last Dragon.

"It's not on the menu. No one is selling it. You can't ask for it. But if you're a regular, an insider, your bartender just might pull out a bottle and offer you a taste."

NOTE: Neither the author nor Popular Science advocate the use of illegal intoxicants.

Gray Matter: Funnels Of Flame

Tue, 16 Apr 2013 16:30:35 GMT

How nature scorches the skies with fire tornadoes.

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Every year I burn down my backyard. Not because I have an unhealthy fascination with fire (which I do), but because my backyard is native prairie. It needs regular burning to maintain the ecosystem. Sometimes I witness fire whirls—spinning columns of flame that last a few seconds and reach 30 to 40 feet into the air. But those are nothing compared to what much bigger backyards can create: fire tornadoes.

Tornadoes are like upside-down drains. Water flowing down a sink spins as centrifugal force interacts with gravity. Similarly, when a column of warm air rises through cooler air, it can form a vortex. If that rising air contains fire, you get a fire whirl or, in extreme cases, a fire tornado—flaring monsters that can reach nearly a mile high and swirl flames faster than 200 mph.

I’ve photographed a fire whirl only once, and I hope I never see a fire tornado. I probably won’t. The only one ever conclusively documented occurred in 2003, after wildfires erupted near Canberra, Australia. Even so, scientists couldn’t confirm what leveled more than 500 homes until they reanalyzed photos of the damage in 2012.

I decided to create my own tabletop fire tornado with USB fans and propane gas. I hooked the fans around a turkey-fryer ring, turned them on, and lowered the fryer’s propane burner into the breeze. It was cheating, as updrafts power the vortex in a real fire tornado, but it still looked cool as the flames compressed into a two-foot-tall twister. (Box fans around a bonfire can create much bigger artificial fire tornadoes.)

By the way, it’s myth that water drains only counterclockwise north of the equator. Fire whirls, like draining water, are too small for the Earth’s rotation to affect them (unlike huge hurricanes). Not that this fact would help if you’re ever caught in one.

WARNING: Play with fire and you’ll get burned. Propane gas flowing into swirling air is an excellent way to test this theory.

You Built What?!: A Tractor For The Apocalypse

Clay Dillow — Wed, 10 Apr 2013 16:00:00 GMT

A modular, open-source workhorse to help rebuild civilization.

Marcin Jakubowski didn’t study fusion physics to become a farmer. But the Polish-American scientist grew more disillusioned with academia the longer he worked toward his doctorate. Researchers withheld data to compete for grants, he says, instead of collaborating to solve big problems. “The further I went in my Ph.D. program, the less value I felt I was contributing to society,” he says. Seeking a fresh start, Jakubowski bought 30 acres of Missouri farmland and a tractor. Life in relative seclusion proved uneventful until, one day in 2008, his tractor broke down for the second and last time, spurring him to start an open-source industrial revolution.

To Jakubowski, the tractor seemed designed to fail. Why should he sink more money into fixing it or buy a replacement? He wanted a simple and useful machine, and one he could repair and upgrade on the fly. “It boiled down to lower cost in the long run,” he says.

Jakubowski built the first LifeTrac, as he calls his DIY tractor, in three months for $6,000—about $30,000 less than a comparable mass-produced model. Seeing room for improvement, he built a second prototype in just six days. He posted his progress on the tractor and other machines to an online wiki, which attracted followers, who suggested their own design tweaks. Some even visited in person to help with builds—and Open Source Ecology took off.

Led by Jakubowski, the group now designs open-source agro-industrial machines on his “Factor e Farm.” The fourth iteration of LifeTrac isn’t like the industrial equipment on most farms; it works with a variety of custom attachments, including two removable, office-copier-size hydraulic engines called Power Cubes. The cubes also power other pieces of the Global Village Construction Set: 50 machines—ranging from 3-D printers and CNC mills to bakery ovens and brick presses—that the group deems essential to modern society (see “Multipurpose Power,” next page).

Jakubowski isn’t preparing for the apocalypse, even though his civilization starter kit might come in handy after one. Rather, he wants to equip the world with affordable tools that enable productive farming, manufacturing, and other accoutrements of civilized life. Open Source Ecology has prototyped 15 of 50 designs so far, and Jakubowski plans to create the rest by the end of 2015.

Once all of the blueprints hit the Web, the group will shift from prototyping to multiplying. The idea: With a few raw materials and a starter construction set, users could copy all the machines. Jakubowski hopes to field-test the concept around the world at centers where people learn to build the machines—and, in the spirit of open source, improve the original designs. “This isn’t about free versus paid,” Jakubowski says. “When people are free to build on each other’s work, innovation can increase exponentially.”

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(Get the specifics of the project on the next page)

HOW IT WORKS
1) Two Power Cubes, each a 28-horsepower gasoline engine that drives a hydraulic pump (inset), lend the LifeTrac its muscle. Quick-connect mounts let users swap cubes into other machines.

2) Hydraulic motors drive the wheels, which operate in pairs to move the 4,000-pound tractor on tank-like treads. When equipped with two Power Cubes, the LifeTrac can drag two tons of weight.

3) LifeTrac’s creators designed their multi-purpose tractor around a frame of sturdy, four-inch-wide steel tubes. Loader arms made from the tubes can lift loads weighing up to four tons.

4) Versatility defines the LifeTrac. In addition to a simple shovel, Open Source Ecology is prototyping attachments such as seeders, rototillers, well-drilling rigs, balers, and brick presses.

MULTIPURPOSE POWER
Maintaining a fleet of machines with different engines is arduous and expensive. The Global Village Construction Set attacks both problems with a single, versatile power source called the Power Cube. Below are a few of the machines and capabilities that a cube could enable by 2015.

High-Tech, Old-School Headphones

Tue, 02 Apr 2013 20:59:31 GMT

Untether your vintage cans using a cheap wireless hack.

Music fan Andrew Wayne loved the funky 1970s headphones he purchased from a flea market. But he didn’t like switching between the vintage pair and modern, wireless headphones compatible with his smartphone. So Wayne simplified his life using an inexpensive Bluetooth adapter. Give your own wired cans some brand-new abilities by following these steps.

INSTRUCTIONS:
1) Buy a Bluetooth adapter (about $15), pry open the case, and set aside its electronic innards.
2) Open your vintage headphones—the larger the cans, the better—and remove the speakers and wiring.
3) Grab one male and one female ⅛-inch stereo jack, plus three short lengths of speaker wire: two split into a Y shape and a third split into an X. Solder one end of a Y-shaped wire to the right speaker’s positive lead and the other two ends to the jacks’ right channels. Repeat for the left speaker and the jacks’ left channels. Solder the X-shaped wire to all ground terminals [see wiring diagram].
4) Plug the male jack into the Bluetooth adapter’s female output. If necessary, drill holes in the headphones’ cans to access the Bluetooth receiver’s on/off switch and USB port. Otherwise, be sure the earpiece can be removed (to charge the receiver and turn it on and off).
5) Hot-glue the soldered connections to prevent electrical shorts, fit the receiver and wiring back into the headphones, and jam out.

Time: 2 to 3 hours
Cost: $20
Difficulty: 2/5

For Wayne's complete build instructions, download this PDF.

This article originally appeared in the May 2013 issue of Popular Science. See the rest of the magazine here.

How Can I Solve A Faraway Relative’s Computer Woes?

Tue, 02 Apr 2013 20:43:31 GMT

Give your granny several states away the tech support she deserves—from a smartphone.

Every family has an unofficial IT guy or girl. When printers won’t print or files can’t be found, the odds are good, dear reader, that you’re the one answering relatives’ panicked distress calls. Unfortunately, troubleshooting can lead to head-banging frustration for both you and your less savvy kin.

There’s an easy fix: Download remote-access software—a program that connects you to a faraway computer so that you see exactly what the other person sees. Even better, you can control that person’s machine with your own mobile device. Instead of a maddeningly slow back-and-forth dialogue, you can take the reins and work some magic directly.

What might this cost you? Nothing if you choose the right product. LogMeIn Free and TeamViewer, for example, offer free remote access on Windows and Mac (the latter software supports Linux too). Both programs are also platform-independent, which means you can control a Mac from a Windows machine or vice versa. They even allow interaction via apps on mobile devices, so you can take charge from your tablet or smartphone.

Now your family can pester you for help, even when you’re on vacation. Whether you answer the phone is still up to you.

This article originally appeared in the May 2013 issue of Popular Science. See the rest of the magazine here.

Build Your Own Resistor Substitution Decade Box

Fri, 22 Mar 2013 13:03:19 GMT

Dial in the resistor you need and avoid digging through messy electronics bins.

If your desk isn’t cluttered, you aren’t doing your job. Gadget-building geeks know this adage well, thanks to resistors. The tiny components police electricity’s flow, yet it can take dozens of kinds to perfect a circuit (such as to spin a motor at a precise speed). Electronics hobbyist George Graves knew devices called decade boxes allowed users to dial in different levels of resistance, but retail models seemed expensive and confusing. So Graves built his own with used parts. Now you can too.

1) Get eight decimal thumbwheel switches.

2) Collect nine identical resistors for each switch, from 1 ohm through 10 megohms. (E.g., nine 1-ohm resistors for the first, nine 10-ohm resistors for the next, and so on.)

3) Set aside one resistor in each set. Bend the leads of the other eight resistors to fit across sequentially numbered pins (e.g., from pins 1 to 2), solder them in place, and trim the leads (see inset).

4) Solder the unbent resistor onto pins 4 and 5 and a piece of wire from pin 9 to pin C. Mark each switch’s magnitude.

5) Stack each switch in order (from high to low), slip a wire through each remaining pin, and solder all of the connections.

6) Secure one wire to the last open pin at the stack’s top and another wire to its bottom. Connect each wire to a banana jack.

7) Wire the box into your circuit, dial in the value you need, and say good-bye to futile resistance.

Time: 5 hours
Cost: $25
Difficulty: 2/5

Click here to see a PDF of the full build instructions.

Gray Matter: Watch A Hybrid Rocket Burn From The Inside Out

Theodore Gray — Mon, 18 Mar 2013 13:00:00 GMT

Seeing through a rocket engine is easier than you might think.

Space tourism front-runner Virgin Galactic hopes to launch customers toward the edge of space later this year. To get them there, in a winged craft called SpaceShipTwo, the company will light up hybrid-fuel rockets.

Hybrid-fuel engines marry two classic designs: liquid-fuel (like the space shuttle’s main engines, which combine gaseous hydrogen and liquid oxygen) and solid-fuel (like the shuttle’s boosters, which use solid aluminum and ammonium perchlorate).

Solid-fuel engines are powerful, but they burn until the fuel is gone—whether you like it or not. Pilots can throttle liquid-fuel engines, but they’re very complex machines. Hybrid-fuel engines are the in-betweens. They burn solid fuel with a liquid oxidizer, which pilots can adjust, but they are far simpler than liquid-fuel engines.

Learning how rocket engines work can be tricky, so wouldn’t it be cool to see through one? This is easier than you might think.

I built a transparent rocket by drilling a half-inch-wide hole through the length of a 6-inch-long by 2-inch-wide acrylic rod. That’s the whole engine: The acrylic tube is the fuel, housing, and nozzle, all in one piece. To ensure the fuel would burn rapidly, I inserted a half-inch-thick metal pipe in one end and blew pure oxygen gas through the acrylic. (Liquid oxygen would be more authentic but far more dangerous; it’s hard to handle and can lead to explosions.)

I stuck a wad of flaming paper towel into the acrylic rod to light it, then opened the oxygen-gas valve to generate a modest amount of thrust. Increasing the gas flow boosted the engine’s power, transforming a gentle pencil flame into a roaring blast.

The rocket is hypnotic: It’s like watching a fire from the point of view of the fuel. The force of combustion drives forward ripples of gooey, burning plastic until finally, the whole cylinder starts to melt. Then it’s time to cut the gas and figure out what to do with a flaming, half-molten mass of acrylic.

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Warning: Do not attempt. Burning acrylic emits toxic fumes and can cause severe burns. Oxygen gas can create powerful, unpredictable explosions.

Raid Your Kitchen To Build This Potato Chip Speaker

Thu, 14 Mar 2013 19:44:08 GMT

For that crispy, crunchy audio

In 1921, two scientists made the first modern loudspeaker out of magnets, wire, and paper. Now manufacturers use synthetic fibers and even ferrofluid. Why stop there? Your kitchen contains plenty of materials to build a functional woofer. A potato chip works as a sound-emitting diaphragm here, but other rigid foods work just as well.

Time: 5 to 10 minutes
Cost: A few bucks
Difficulty: 1/5

1) Gather the parts
25 feet of 30-gauge magnet wire
Two ¾-inch-diameter-by-¼-inch cylindrical refrigerator magnets
Two cardboard strips, ½ inch by 1.5 inches
A wooden cutting board or piece of particleboard
One 6-inch-long, ¾-inch-diameter dowel
Sandpaper
A hot-glue gun
Potato chips (thick-cut chips work best)

2) Build a voice coil
Wrap the magnet wire tightly around the dowel to make a ⅜-inch-tall coil, leaving 12 inches of wire on each end. Smear the coil with hot glue, let it cool, and slide the coil off the dowel. Sand an inch of paint off the wire’s ends.

3) Assemble the speaker
Fold the cardboard strips into a Z shape. Hot-glue the magnets and strips to the particleboard, and then the coil to a chip. Next, glue a cardboard strip to each end of the chip while centering the coil over the magnet.

4) Rock out
Connect the sanded speaker wires to an amplified audio source, such as a home entertainment center (a portable player may lack enough power), and listen to the saltiest, crispiest music you’ve ever played.

Happy Pi Day! 10 Useful Things You Can Make With A Pie Tin

Rose Pastore — Thu, 14 Mar 2013 15:00:00 GMT

In honor of Pi Day, why don't you try one of these fun crafts from the Popular Science archives? Use a pie tin to make a jet engine, a telescope, or a lovely chandelier.

Today is Pi Day (the cool cousin of January 23's Pie Day) and, to celebrate, we've compiled 10 fun and easy pie-tin crafts from the Popular Science archives.

What do a hipster chandelier, an amateur telescope, and a living-room jet engine have in common? You can make each one with an ordinary pie tin!

Click here to enter the gallery

A version of this article originally appeared January 23, 2013.

Build Your Own DIY Space Plane

Kelsey D. Atherton — Mon, 11 Mar 2013 21:00:00 GMT

A Swedish man modified an RC airplane, stuck a camera on it, and then flew it to space and back.

One of the more delightful YouTube video genres involves sending a camera into towards the blackness of space beneath a weather balloon. The first one I ever saw featured a father and his young son in Brookyln. Other have used it for everything from college admission letters to Hello Kitty to Natty Light, to even a LEGO version Felix Baumgartner's jump. Okay, that last one didn’t actually make it to space, but it fits the genre: slow launch, frantic first person footage as it plummets, and then a triumphant recovery. Most of these drops rely on a tough camera casing that can survive the fall back to Earth.

David Windestål of Sweden had a different idea. What if, instead of just sending a camera into space, he sent a drone? Well, technically an RC model plane. Here's how he did it:

Start with a model airplane

Windestål picked the FunJet, an RC plane with enough interior space to hold the gadgets he wanted to add.

Add a video transmitter

The video transmitter allows for first-person-view remote control flying. Essentially, it gives the controller a view from the camera mounted inside the cockpit, allowing Windestål to fly the plane as though he were on board. Windestål chose the Lawmate 1W 1.2GHz, a transmitter with an overheating problem that actually becomes an asset in the cold upper atmosphereof space.

Cut the balloon

The most inventive part of Windestål's design is the mechanism that releases the plane from the hydrogen balloon that carries it to space. While it didn't work perfectly in flight, the device is still a good solution to a tricky problem. When the balloon that is carrying the plane gets high enough, it will inevitably burst as the gas inside expands beyond the ability of the balloon to contain it. When that happens, the tangle of balloon risks getting in the way of the radio antenna and covering the camera. Not fantastic. To try to cut the plane loose from the balloon before that happened, Windestål tied a wire around the string holding the balloon, and then at the flick of a switch ran more electricity through the wire than it was rated for, causing it to burn through the rope over the course of 10-30 seconds.

Enjoy the fall

After the modified FunJet disconnected from the balloon, it began plummeting toward Earth. Windestål got control of the plane after 20 minutes and was able to fly it back to the ground, steering it past a road before gracelessly striking a tree. Watch the video below:

Windestål put together a detailed DIY guide describing how he constructed his space plane. One word of caution: Helium is very expensive in Sweden, so Windestål instead used highly flammable hydrogen to inflate his balloon. If hydrogen in balloons sounds familiar, that’s probably because of the Hindenburg,, an airship which caught fire and exploded in 1937. Windestål recommends against using hydrogen, and I can’t agree more.

Magic Mystery Bulb

Fri, 08 Mar 2013 16:09:34 GMT

Transform an old lightbulb into a glowing April Fools’ prank.

The Addams Family’s Uncle Fester is famous for popping lightbulbs into his mouth and making them glow. The TV trick inspired Kip Kedersha, a fan of the series, to build a prank lamp using an LED, batteries, and an old bulb. Create your own and light up a room on April 1.

1) Wearing thick gloves, carefully twist a glass lightbulb out of its metal base and save both parts. Discard the filament.

2) Solder a 2-inch wire to the base’s inside center and another to the side. Stack and zip-tie two three-volt button batteries.

3) To the short lead (anode)of a white LED, solder the center wire. Tape the other wire to the battery pack’s negative end.

4) Tape one end of a third wire to the battery pack’s positive terminal. Solder the other end to the LED’s long lead (cathode).

5) Coax the LED into the glass, fit the battery pack and wires into the base, and reconnect the bulb’s two pieces with hot glue.

6) Grasp the base, touching a wire that’s hidden in your hand to its side and bottom. To the surprise of your pals, it should light up.

Time: 1 hour
Cost: $4
Difficulty: 1/5

WARNING: Broken glass can cause deep cuts and gashes. Do not screw the modified lightbulb into any socket.

This 'DRM' Chair Will Self-Destruct After Eight Uses

Colin Lecher — Mon, 04 Mar 2013 17:02:50 GMT

It's like a high-tech, sadistic version of musical chairs.

DRM CHAIR from thibault brevet on Vimeo.

This is a self-destructing chair, and also happens to be a pretty darn funny political statement.

Ever heard of DRM? It's tacked on to software to push back against piracy. You might get a limited number of downloads for certain content, for example, ensuring you can't post it up on the web for everybody with an internet connection to download.

So a team of designers expanded on that idea. What if everyday objects functioned like they were DRM-ladened? Well, it might look something like this chair, which self-destructs after eight uses.

The team thought up, built, and videoed the project in 48 hours for a design competition. A pressure sensor counts the number of times it's been sat on, and an Arduino triggers the joints to melt after eight sits.

Don't worry: it waits until the eighth sitter has walked away before it falls apart.

[Vimeo via Hexus]

How One Group Is Trying To Skirt Federal Regulations On Its $50 3-D Printed Gun Part

Kelsey D. Atherton — Thu, 28 Feb 2013 19:30:00 GMT

A crowd-funded 3-D printing project seeks to make a "some assembly required" gun part.

Enthusiasts of gun-law loopholes, this might be your new favorite workaround. A project at the crowd-funding site Rockethub wants to create a 3-D printed gun part for just $50. The twist: the part is only 80 percent complete, so like an Ikea desk you'll have to finish the rest of it yourself.

Started by 2nd AM Arms, the project promises to make a lower receiver for an AR-15 semiautomatic rifle. The lower receiver is what holds all the working parts in a gun. The receiver is so important that under U.S. law, a receiver on its own is still treated as a firearm, and requires a serial number. The argument made by 2nd AM Arms, however, is that an 80-percent completed receiver is just part of a gun component, not a full-blown firearm, and as a such is not subject to the same degree of federal regulation.

What that might mean: Buy it, and you could have complete anonymity. A licensed seller of complete gun parts "must maintain records of all firearms receipts and dispositions, including the name, age, and place of residence of purchasers." That's not the case when selling an 80-percent complete part. 2nd AM Arms FAQs says under facts that it will "even accept cash or gold if you like as payment for those who would like to stay completely anonymous."

So what would someone do with 80 percent of a gun part? At its Rockethub page, 2nd AM Arms links to YouTube videos detailing the kind of drilling and modification someone would need to take a part like this and make it functional.

Making the lower receiver is only one of the goals of this project. Obviously, there's a larger agenda here: to send a political message. Just look at the other donor rewards. At the lowest level of support, 2nd AM Arms will mail a copy of the 2nd Amendment to President Obama and Sen. Dianne Feinstein (D-California), both of whom have expressed interest in stricter gun laws. All higher pledge levels include T-shirts featuring the 2nd Amendment, and if you pledge anything above $50, you get a commemorative lower embossed with the 2nd Amendment. Finally, if the project meets its funding goal (which it had as of press time), 2nd AM Arms pledges to donate 2 percent of its funding to the NRA.

Earlier this week we described the continuing developments of Defense Distributed, a band of 3-D printed gun advocates, to make a 3-D printed lower receiver. Both of these 3-D printed gun projects have a political intent, and it's interesting to see the different ways they are aiming to skirt regulation. With Defense Distributed, it's about people freely downloading schematics. With 2nd AM Arms, the dodge is by offering only a mostly complete product.

The World's Nerdiest Marriage Proposal

Francie Diep — Tue, 26 Feb 2013 17:30:00 GMT

Physics nerds in love.

Did it undergo peer review first?

A physicist posted this marriage proposal from her boyfriend, also a physicist, on Imgur a couple days ago. The proposal somehow combines features of both advanced academic writing and a note that you might pass in class to your first-grade crush:

This reviewer approves. Go here for a zoomable version.

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You Built What?!: A Tractor For The Apocalypse

High-Tech, Old-School Headphones

How Can I Solve A Faraway Relative’s Computer Woes?

Build Your Own Resistor Substitution Decade Box

Gray Matter: Watch A Hybrid Rocket Burn From The Inside Out

Raid Your Kitchen To Build This Potato Chip Speaker

Happy Pi Day! 10 Useful Things You Can Make With A Pie Tin

Build Your Own DIY Space Plane

Magic Mystery Bulb

This 'DRM' Chair Will Self-Destruct After Eight Uses

How One Group Is Trying To Skirt Federal Regulations On Its $50 3-D Printed Gun Part

The World's Nerdiest Marriage Proposal