By Gregory MonePosted 09.12.2007 at 4:55 pm2 Comments
This clip of a 4X4 speeding up a ridiculously steep face looks like a once-in-a-lifetime accident, but dune-climbing is actually a sport. Tens of thousands of people show up for events like this in the United Arab Emirates and other sandy locales. The driver of this vehicle undoubtedly has a serious combination of guts and skill, but apparently there's nothing all that special about the car
Everything but the engine, and the driver who's gunning it, wants this car to roll back down the hill. Gravity in particular. The key here is momentum, which is a function of mass and velocity. Basically, the driver needs to get the car flying before hitting that slope. Once he starts heading up, he probably downshifts, since he wants to keep his RPMs as high as possible as the car starts to climb, and retain some of that momentum. The tires on the car are probably deflated slightly, too. This increases the surface area over which the weight of the car is distributed, and makes it a little less likely to sink into the sand. Just how steep is the slope? Our viewing angle tricks things up a bit. You can see once the car nears the top that the slope's not quite as vertical as it looks from a distance.
Towards the top, the fact that the driver flips, then rights himself, is absolutely amazing. There's clearly a mixture of luck and skill involved here, but he's helped in his descent by the fact that most of the mass, and the momentum, is carried up front. The car wants to go down head-first.
By Gregory MonePosted 09.07.2007 at 12:17 pm2 Comments
Hydrofoil surfing is just one of those things that doesn’t look right when you see it for the first time. These guys are surfing, riding down the face of a wave, and yet the board itself is more than a foot above the surface. Huh?
In this video, the foil is attached to the bottom of the board via a single strut. After a jet-ski pulls the surfers up to speed, allowing the hydrofoil to push board and rider up out of the water, they let go of the tow rope and let the power of the wave take control. Terry Hendricks, a physicist and long-time surfer who has designed an innovative wave-rider of his own, says the foil effectively acts like an underwater glider. When the surfers are coasting down the face of the wave, the water itself is rushing upward, getting sucked up by the energy of the swell. This rushing water acts like an updraft in the air, generating lift—only in this case it’s keeping the foil flying instead of a glider.
The real trick, though, is balance. Hendricks compares the form of hydrofoil surfing practiced in this video to riding a unicycle. The rider is balanced over that single strut, and there are probably 30 inches between the bottom of the board and the foil below the water. His own model uses two foils, front and back, and a bodyboard approach. The rider lies down, kicking into the wave. This makes it easier to balance but produces a much bumpier ride, since the leading foil stays at water level. With the surfers shown here, on the other hand, the single foil is a good distance below the surface most of the time, so they’re completely avoiding wind chop, and smoothly cruising down the face of waves that look like mogul hills. Ready to try it out?—Gregory Mone
By Gregory MonePosted 08.29.2007 at 5:58 pm0 Comments
The nearly 6,000-foot-long Tacoma Narrows Bridge, known as Galloping Gertie, opened up on July 1, 1940, and collapsed just four months later. Winds reached 42 miles per hour on that fateful day, which proved too intense for the structure. There were a number of causes, but the basic problem was that engineers hadn't yet learned to account for wind loads in their designs. During the planning phase, the engineers reduced the proposed depth of the concrete and steel girders beneath the roadway from 25 to 8 feet. This loosened the stiffness of the road, and made it much more susceptible to wind. In fact, before the collapse, local residents had noticed that less intense gusts could cause the bridge to move. But those movements involved longitudinal waves – one end of the bridge rose, the other fell, in a less dramatic fashion than what we see in one of the early scenes in this clip.
Prior to the collapse, though, the wind induced torsional movement. In other words, the road started to twist. While the center line stayed stable, one side of the roadbed rose and the other dropped. When this twisting motion peaked, the sidewalk on one side was 28 feet higher than the opposite one.
Eventually, this twisting motion proved too much for the structure. The cables started to snap, and chunks of the bridge fell into the water below. Finally, the entire center collapsed. With this mass gone, the sections on either end sagged dramatically, dropping more than 40 feet. Nowadays wind-tunnel testing is fairly standard for bridge designs. When engineers drew up the plans for Gertie’s replacement, which has been standing for more than 50 years, you can bet they spent a lot more time factoring in the breeze.—Gregory Mone
Posted 08.29.2007 at 11:56 am 3 Comments
Now you can get our five minute project videos delivered directly to iTunes or any other podcasting app. Subscribe here via iTunes, or use our RSS feed (http://popsci.libsyn.com/rss).
Some of you may be wondering what cruel fate may have befallen our brave podcaster Jonathan Coulton out on Lunar Base One. Well, a critical Doritos shortage after a lunar cargo supply chain error left Jonathan with a choice: continue to broadcast his weekly dispatches in solitude on the moon sans Doritos, or return to Earth to devote his full energies to being the interstellar rock star that he is, with the added benefit of all the Doritos he could eat. I think we can all see how the latter option won out. We wish our contributing troubadour all the best—you can still relive all the excitement via the same RSS feed in iTunes where every episode is archived.
We are happy to announce the winner of our Go Green contest, thrown over on Instructables with the help from our friends at TreeHugger. The winning project details an ingenious way of further purifying the effluent water output of a sewage treatment tank (also designed by the contest winner's organization) and using it to grow plants in a hydroponic garden. Well done! Stay tuned here for more of our favorite entires, published in their step-by-step glory. Congratulations and thanks to all who entered! —John Mahoney
By Gregory MonePosted 08.22.2007 at 4:19 pm6 Comments
This video of legendary climber Dan Osman looks downright impossible. The camera has to be tilted. And the playback must be in fast-forward mode. There’s no way someone could scale a cliff that quickly, right? Actually, Osman’s Spidey-like ascent is the real thing. And in rushing up that rock, he demonstrates both the incredible capabilities of the human hand and the importance of not trying to test the laws of physics. First of all, friction is your friend in rock climbing, and during one close-up you can see that Osman is wearing very flexible, grip-enhancing shoes. The flexibility of the soles is critical because it puts more of the rubber sole in contact with the rock, increasing the friction, and the chances that his foot stays planted in place.
The rock itself, known as “Bear’s Reach,” would be considered an easy one for experts, offering numerous cracks and bumps and ledges large and small. In other words, Osman’s not climbing up a smooth wall. And when he’s jamming his fingers into one of those cracks, or grabbing a ledge, he’s basically proving that our evolutionary ancestors swung from branches. There’s no other good reason for our hands to be that strong, and capable of supporting so much weight. By pressing his fingers down on some exposed rock, Osman engages more of the muscles in his forearm, allowing him to bear more weight on that hand.
Obviously he’s also in ridiculously good shape. One Web site says the climb should take about three hours. In this video, Osman does it in 4 minutes and 25 seconds. Tragically, though, this daring approach to nature’s dangers led to Osman’s early death in 1998, at the age of 35.—Gregory Mone
I just wanted to thank everyone who entered our "Go Green" contest over on Instructables—and everyone else who submitted great greening ideas to the original post's comment thread. We're thrilled with the great response we've gotten, and it'll be a tough job judging all the entries. Stay tuned here for the winner's announcement and several of our favorite projects. —John Mahoney
We're sorry to report that PPX is temporarily out-of-service due to a network-wide problem. Our technical team is working hard to rectify the issue. We estimate that it will be back online in an hour or two, and we apologize for the inconvenience! —The PopSci.com Team
Note to the Reader: For those of you who haven't seen Fantastic Four:
Rise of the Silver Surfer, yet are serious enough about it that you
want even the most trivial plot details kept secret until you actually
watch the movie, what follows will be a bit of a spoiler. (A rough
calculation makes us think there are about three of you out there.)
For the rest of you, don't worry, this little detail won't ruin
So, Reed Richards, aka Mr. Fantastic, is sitting in his lab trying to
think of a way to separate an alien from his cosmic surfboard when he
gets an idea. "A tachyon burst!" he exclaims.
Fast-forward a few scenes. A series of devices capable of delivering
said burst are built, one is activated, and the aforementioned alien,
known as the Silver Surfer, is cleanly knocked from his board.
Now, would this really work? Tachyons are theoretical particles
believed to travel faster than the speed of light. Trying to think
about what effect they would have on a liquid-silver alien can be
thoroughly mind-bending—would they send him back in time or even
arrive at their target in the past, thus having no effect whatsoever?
So, we appealed to University of Washington physicist and science
fiction author John G. Cramer, who has the scientific and imaginative
chops to handle such questions.
First, Cramer notes that knocking the surfer off his board would
require a transfer of momentum. And while the momentum of the
hypothetical tachyon beam would be relatively small, there might be
another, more dramatic effect. "The delivery of energy would be much
more efficient than the delivery of momentum," Cramer says, "so it
seems more likely they would blow the Silver Surfer apart rather than
knock him around."
Instead, Cramer proposed another, decidedly less-sexy idea. "I think a
cannonball or an artillery shell would work a lot better."
So, Mr. Fantastic, next time you try to save the world, do it the
old-fashioned way.—Gregory Mone
The PopSci staff and our contributing troubadour, Jonathan Coulton, have spent today combing through the remarkable array of "I Feel Fantastic" videos sent in by loyal readers and podcast fans. After much deliberation and humming of that annoyingly catchy refrain that just won't get out of our heads, we arrived at a winner. This stick-figure animation, by YouTube member AnnieKate76 made us laugh our collective butts off. Says JoCo himself, "I like AnnieKate's video because it's got this very simple visual
look, but it's deep, man. I keep noticing new stuff every time I watch it, all these quick cuts to funny things. It's like an episode of Lost, but funny, and with stick figures." Right, what he said. So without further ado:
For her hard work and hilarity, AnnieKate76 will receive the grand prize of one 80 GB iPod, custom-engraved with Jonathan Coulton's autograph. Congrats!
But there were so many excellent entries that we decided to name five honorable mentions who put tons of work into creating really excellent animations, machinima and live-action music videos. Each of the five co-winners listed below will receive a free subscription to Popular Science. Great job, everyone!
First runner-up goes to YouTube member Demetrius3d, using Lightwave 3D animation:
Second runner-up goes to YouTube member ThrowingBricks, using The Sims 2 machinima:
Third runner-up goes to YouTube member theshirtevent, using Flash:
Fourth runner-up goes to YouTube member Zeedoos, using World of Warcraft machinima:
And fifth runner-up goes to YouTube member team blackcatbonafide, for their live-action music video:
Many thanks to everyone who submitted a video! If you're one of the winners mentioned here, please contact us again via YouTube with your name and address, so we can send you prizes. Look for more PopSci contests in coming months (hint: if you like making stuff, you'll want to check out our "green tech" challenge beginning July 10. —The PopSci Editors
If you've already tuned in to Jonathan's latest podcast episode, you may be wondering what the contest he mentioned is all about. As he said right before the Lunar Base One lockdown was complete, we're giving away a brand-spanking-new 80-gigabyte iPod complete with a laser-engraved JoCo autograph on the back to the fan who cranks out the coolest music video to accompany “I Feel Fantastic,” the smashing power-pop number about how a future life might be better with a handful of specialized performance-enhancing pills. It's just one of five great songs Coulton wrote to accompany PopSci's Future of the Body issue.
So crank up the webcam and karaoke your heart out. Or throw together a touching Ken Burnsian photomontage. Or make a flip book and film it. We'll take anything. The most fantastic entry will bag the iPod (bear in mind, this isn't some lame-o Apple-engraved message—we'll be taking this down to Brooklyn to have Mr. Coulton's official mark engraved on Phil and Limor's Epilog laser cutter. In short, it's going to look awesome).
To enter, download the track here. Then submit your video to YouTube and send it as a video message via YouTube to “Popscivideo” (our YouTube user name). Please include “Coulton Contest” in the subject line and—if you don't want us to contact you through YouTube if you win—your e-mail address. We'll be taking entries until the contest closes on June 18, so get cracking!
Check out some classic Coulton fan videos after the jump for inspiration (as well as some good ol' legalese) —John Mahoney
By Jonathan CoultonPosted 05.21.2007 at 12:29 pm1 Comment
Yes, I know, it's been a long time since I posted a podcast. I've been very busy here on the moon doing...important things. Let's not discuss it anymore.
PopSci editor Nicole Dyer is obsessed with paint, in particular the new Aura paint from Benjamin Moore. Not only does it cover most colors with only one coat (no need for primer), but it's low in smog-producing VOC's, dries quickly and doesn't stink. Nicole was so excited about it, and her excitement was so infectious, that we both forgot to even talk about the breakthrough chemistry that makes it possible - new and improved surfactants that bond better with pigment molecules. That's how exciting this story about paint is.
I also asked her for an update on the "Red Rain" story from an earlier podcast, but as you'll see, the paint insanity seems to have distracted her from more important things (like aliens)—Jonathan Coulton
Of all the phenomenally difficult, profoundly asinine ways to get into the Guinness Book of World Records, this high-dive-into-shallow-pool feat has got to be one of the worst. Me? I’d rather walk backward for a while, à la Cliffy in Cheers, or try to master one of those balancing-balls tricks.
That said, someone did put a little bit of thought into this setup. First, there are a few sequences in the video that afford a wider view of the glorified kiddie pool and reveal that the base is a cushioned mat of some sort. This proves critical: If you watch closely, you can see the jumper bend his knee just before impact. His knee enters the water like a wedge—albeit a rounded one. If that was a real floor underneath the water, he wouldn’t have been capable of standing up and throwing that double-fisted pumper at the end.
Second, aside from that knee drop (undoubtedly a last-second effort by the diver’s brain to abort), he does have fairly perfect technique. University of Virginia physicist Lou Bloomfield says the belly-flop posture is the key to stopping short in that shallow pool. “For him to avoid injury, he has to use as much of his surface as possible to get rid of his downward momentum,” Bloomfield says. “A good belly slam helps.”
One thing science won’t be able to tell us, though, is why he’s wearing that god-awful unitard. —Gregory Mone
Ah, so that's what they teach you in those Buddhist monasteries. Meditation? A clear mind and heart? Whatever. To achieve oneness with the universe, you need to learn how to stick a rice bowl to your stomach.
The miniature monk in this clip has two things working in his favor: his munchkin-like stature and basic physics. By sucking in his midsection, then pressing the bowl to his stomach, he creates a partial vacuum in the space between the bowl's inner surface and his skin. Since the seal is tight and there are fewer molecules of air per cubic inch inside the bowl/stomach space than there are outside, the bowl sticks.
Now, as for how it stays there while he's being lifted clear off the ground, that's where the apparent lack of McDonald's hamburgers and soda in his diet factors in. Let's assume he weighs about 50 pounds, and the bowl covers about 30 square inches of his belly. In this case, University of Virginia physicist Louis Bloomfield explains that for the seal to hold, the boy only has to reduce the air pressure inside the bowl by a little more than 1.6 pounds per square inch of bowl-bound skin. (Which shouldn't be too hard.) That way, the pressure force pushing him upward against the bowl will reach 50 pounds, balancing the downward pull of his own weight.
Add a video and presto, millions of people across the world get to watch him hanging inverted and upside down, while staring at their monitors thinking . . . huh?—Gregory Mone
It breaks faster than a Mariano Rivera cutter. It's harder to hit than Rick Vaughan's fastball in the movie Major League. The gyroball is so elusive, in fact, that some speculate that it might not even exist. The gyro, which originated in Japan, is causing consternation in American baseball broadcast booths these days. But since science is fairly used to dealing with things that may or may not exist (extra dimensions, anyone?), we figured we'd give it a look.
This video shows Daisuke Matsuzaka, the new Boston Red Sox hurler, supposedly striking out a batter using the gyro. Before we get into how it works, let's look at two other popular pitches. For a normal fastball, the pitcher puts backspin on the ball, so air flows faster above the ball than it does below. The ball doesn't drop as quickly as it would if it were following a normal, gravitationally influenced path, so the batter's brain gets the impression that it's rising. And... he whiffs.
A curveball has the opposite effect: Topspin causes it to fall faster. And again, if all goes well, he whiffs.
The gyroball is said to move with a bulletlike rotation that prevents it from dropping like a curve or staying high like a fastball. In effect, it's a fastball that listens to gravity, following a trajectory unaffected by turbulence in the air.
Japanese scientist Ryutaro Himeno is widely credited with creating the pitch using computer simulations [see the published paper and video clips of the computer models here] with the help of baseball instructor Kazushi Tezuka. They published their work in a book, currently available only in Japan, called The Secret of the Miracle Pitch.
As for whether Dice-K, as he's known in the U.S., is actually throwing a gyroball in this video, that's hard to tell. Following Occam's Razor, the easiest way to find out would be to just ask him, right? That's not so easy, though. Numerous interviewers have tried to do just that, but he’s played coy, allowing the miracle pitch to remain a mystery. —Gregory Mone
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.