Archive for August 2018

A white noise machine

Color-coding sound

During the summers when I was growing up, my bedroom had an air conditioner mounted in the window. I loved the hot nights when I got to turn it on, but only partially because it cooled the room. What I liked best was the sound, which I found to be very soothing. Years later, when I was in college, I had a classmate everyone made fun of because he couldn’t go to sleep without having a radio on next to his bed—playing static. For some reason, the sound of static on a radio seemed goofy in a way that the sound of an air conditioner did not, but they amounted to roughly the same thing: white noise, which has a well-known ability to promote sleep by masking other sounds.

Most of us have seen white noise generators that are sold as sleep aids—sometimes especially for infants. A different class of white noise generator is used for testing and calibration of pro audio equipment. But what exactly is white noise, how does it work, and why is it called “white”?

Pure Noise

If you think back to elementary-school science classes, you probably learned that white light is a combination of all the other colors of light; using a prism, we can separate it into its component colors. By analogy, “white” noise is composed of sounds of every frequency within the range of human hearing—roughly 20 to 20,000Hz (cycles per second)—with each part of the frequency spectrum equal in amplitude (volume). It’s called “noise” instead of “sound” because it is random in nature. Rather than simply generating a fixed tone at 20Hz, 21Hz, 22Hz, and so on all the way up to 20,000Hz, a white noise generator creates a constantly changing mixture of tones such that all frequencies have an equal probability of being audible at any given moment.

To human ears, white noise sounds like a hiss—sounds such as a waterfall, an aerosol can, and static are all similar to white noise. Although all frequencies are represented, we perceive white noise as being relatively high-pitched—partly because higher octaves consist of a greater range of frequencies than lower ones (giving the higher-frequency sounds proportionally more energy), and partly because our ears are more sensitive to higher-pitched sounds.

White noise is good at masking most other kinds of sound because it effectively overloads or “numbs” our auditory systems. Just as it’s difficult to hold a conversation at a crowded restaurant, it’s difficult for your brain to identify any one sound or voice when you’re already hearing sound at every frequency. So it’s not the white noise itself that promotes sleep as much as the fact that it reduces audio clutter, drowning out other sounds that may distract you and therefore keep you awake.

The Color of Sound

If “white” noise includes sound at every frequency, you might imagine it would be possible to create other “colors” of noise by emphasizing certain ranges of frequencies over others. And you’d be right. There is such a thing as pink noise, as well as red, orange, green, blue, purple, gray, brown, and even black noise. Of these, pink noise is the most common—and the most clearly defined. Whereas white noise has equal energy at every frequency, pink noise has equal energy within each octave—in other words, the amplitude at higher frequencies is reduced to make it sound more balanced to the human ear. Pink noise is used for, among other things, calibrating speaker systems. The term “pink” signifies that it’s like white, but “tinted” or weighted toward the lower-frequency (and therefore longer-wavelength) sounds. However, not all of the so-called noise colors map onto the visible spectrum so clearly—and in any case, the color names are nothing more than a convenient metaphor to describe white noise that has been filtered in various ways.

Many of the products claiming to produce white noise are recordings or simulations of wind, waves, and other sounds that are in reality quite a bit more complex than white noise. Not that there’s anything wrong with that—the sound of rain on the roof can be very soothing and can have most of the same masking benefits as white noise. And just as the term “white noise” can be stretched somewhat in meaning to include what you might call “off-white” noise, it also can have a more metaphorical sense, as in “meaningless chatter.” But what I’d like to hear is a recording that sounds just like my old air conditioner—complete with the hum that the compressor made every time it came on. For me, that would beat a melatonin tablet washed down with a glass of warm milk.

Note: This is an updated version of an article that originally appeared on Interesting Thing of the Day on October 16, 2004.

Image credit: By Morn [CC BY-SA 4.0], from Wikimedia Commons


Source: Interesting Thing of the Day

Trail mix

Someone decided August 31 should be National Trail Mix Day. I’m not convinced trail mix needed a day, but OK. According to a bunch of random websites, what we know as “trail mix” today was invented by a couple of surfers in 1968 who decided to mix raisins and peanuts. That may or may not be true. But that particular mixture, sometimes referred to as GORP (good old raisins and peanuts) is something I would not personally take on any trail. Now, replace the raisins with, say, dried cherries or cranberries, add some chocolate chips or M&Ms, or both chocolate chips and M&Ms, and also almonds and, I don’t know, probably some bacon bits or something, and we’re starting to get somewhere. But hey: you do you. If you want to eat flawed trail mix, far be it from me to interfere.


Source: Interesting Thing of the Day

Leonardo's robot

Renaissance man meets mechanical man

As I have mentioned numerous times, I was obsessed with science and technology as a child. I was especially fond of robots—both real and fictional. The magazines I read showed glossy photos of household robots that could vacuum the carpet and serve drinks; it was clear that human beings would no longer have to do such menial tasks in the future. It was less clear that robots would ever be able to do truly useful tasks like repairing the plumbing or washing the windows, but this was unimportant to me. All I cared about was that robots were cool. If they could move around and impress my friends, that would be good enough.

Naturally, I dreamed of someday building my own robot, and even made an abortive attempt to do so when I was about 12. But I was equally happy tinkering with smaller, less-ambitious projects. My bedroom was always full of wires, batteries, motors, solar cells, and electronic doohickeys of all sorts. When I wasn’t disassembling a TV or radio, I spent a lot of time (and money) in Radio Shack buying components that I could assemble into some amazing contraption. The only problem (apart from my rather incomplete grasp of electronics) was that I had trouble figuring out exactly what I should make. What task needed to be done that a gadget could perform? I couldn’t figure it out. So I was constantly asking my mother, “What can I invent?” She’d invariably say, “If I told you, then I’d be the one inventing it.” That was beside the point, of course—it was really the engineering I was interested in, not the idea-generation itself.

Renaissance Robotics

A little over 500 years earlier, Leonardo da Vinci was in just the opposite situation: coming up with ideas for inventions left and right, but doing comparatively little in the way of actual experimentation and implementation. Of course, I do not in any way mean to belittle Leonardo’s remarkable achievements in so many different fields, but he did have somewhat of a reputation for coming up with half-baked ideas that were never constructed—and in many cases, wouldn’t have worked if they had been. His human-powered helicopter design is perhaps the best-known of these wouldn’t-it-be-nice “inventions.” On the other hand, Leonardo’s sketches did contain a lot of designs that showed uncanny cleverness and sophistication, far ahead of his time. Among these are drawings that experts today believe were designs for robots—which, if true, would make Leonardo the world’s first roboticist.

The sketches in question were made around 1495, but were unknown until an Italian scholar named Carlo Pedretti found them in the 1950s. Nothing in the several pages of drawings looks like a complete robot; the gears, pulleys, cables, and so on appear to untrained eyes to be random machine components. But Pedretti believed that taken together, they could represent the plan for a mechanical man. Leonardo apparently intended a suit of armor to be used as the robot’s body. Several decades after the sketches’ discovery, a robotics expert named Mark Rosheim came across Pedretti’s description of Leonardo’s robot. Rosheim studied the drawings extensively and, using computer simulations, determined exactly how they could have fit together to form a humanoid robot. The digital model of the robot showed that it could sit up, wave its arms, bend its legs, move its head, and open and close its jaw; a mechanical apparatus in the chest controlled arm movements, while an external crank moved the legs.

Getting with the Program

Leonardo’s humanoid robot was clearly based on his long and detailed study of human anatomy—the same research that had led to his famous Vitruvian Man drawing and its accompanying list of proportions in about 1490. But apparently, this was not Leonardo’s first foray into the world of robotics. An earlier drawing, from 1478, was thought for years to be the design for a spring-powered cart. But Rosheim’s analysis showed that it was much more than that. The mechanism inside could be adjusted (by replacing various cams) to determine the course the cart would travel. In other words, it was, in a manner of speaking, a programmable analog computer—and since it was also mobile, it could be considered a robot.

Most experts consider it unlikely that Leonardo ever built the robots shown in the sketches. Rosheim, however, did build a reproduction of the cart, as well as a version of the robot that maintained Leonardo’s overall design but substituted a few pieces of modern technology, such as electric motors. Both functioned as Rosheim’s computer models had predicted, meaning that Leonardo’s designs were right on the money, even if he never did build them. The robot doesn’t do anything useful—unless you consider entertaining and impressing your friends useful, which I certainly do. I’m sure Leonardo would have agreed.

Note: This is an updated version of an article that originally appeared on Interesting Thing of the Day on May 12, 2005.

Image credit: Photo by Erik Möller. Leonardo da Vinci. Mensch – Erfinder – Genie exhibit, Berlin 2005. [Public domain], from Wikimedia Commons


Source: Interesting Thing of the Day

A metal Slinky

Having spent most of my childhood in the 1970s, when I see the word “Slinky,” I immediately think of this jingle. And now, with kids of my own, I’ve had to purchase, untangle, and otherwise interact with countless Slinkies, both metal and plastic. Let me just say: it’s a fantastic idea, but even if you’re three, the novelty soon wears off. (And if you happen to live in a house with hardly any stairs, as we do, it’s even less fun.) But! Today is Slinky Day, so if you want to relive those brief moments of joy from your childhood, head on over to your favorite online retailer and fetch yourself some Slinkies!

Image credit: By Roger McLassus (Picture taken and uploaded by Roger McLassus.) [GFDL or CC-BY-SA-3.0], via Wikimedia Commons


Source: Interesting Thing of the Day

A Charles Atlas ad

Isometric blast from the past

I’m not what you’d call a “fitness freak.” I’ve spent enough time in gyms to know how the machines work and experience the sensation of building up a sweat, and I practice t’ai chi regularly. I also do a fair bit of walking around my neighborhood. But working out for its own sake is not really my idea of a good time. My disenfranchisement with exercise goes way back. All throughout school, I was the kid who got picked on in phys. ed. classes—the last one chosen for teams, the slowest in races, the kid who couldn’t do a chin-up if his life depended on it. The shared trauma of phys. ed. embarrassments from high school strengthened my bond with my wife. When we were first dating, I asked her how she felt about exercise, and she replied, “My motto is: ‘no pain, no pain.’” A woman after my own heart.

A number of years ago I stumbled across an ad that made me laugh: it was one of those Charles Atlas comic-book ads from the 1930s. You know the basic idea: the skinny 97-pound weakling gets sand kicked in his face at the beach, but he can’t stand up to the bully so he loses the girl. Then he sends for Mr. Atlas’s program and one frame later, he’s admiring his new body in the mirror. He goes back to the beach, decks the bully, and gets the girl. The ad then goes on to show a photo of a smiling Charles Atlas with the caption “The World’s Most Perfectly Developed Man.” The reason I laughed at the ad was not just that it reflected a long-forgotten advertising style or that Atlas looked goofy in his leopard-skin briefs; I laughed because the ad was on a website, and after the better part of a century, the program was still being sold. Curiosity got the better of me and I sent in my US$50. (The price has since gone up slightly, to $54.95.)

Pages of History

What I got in the mail about two months later was a slim three-ring binder with about 60 photocopied pages inside: the 12 lessons in the original Atlas program, intended to be worked through at the rate of roughly two lessons every two weeks. These could have been exactly the same pages sent out to skinny kids 30 or 40 years ago, except for the URL and email address at the tops of the pages. For $50, I would have expected a slightly more modern and professional presentation, but I figured, I’m not just paying for exercise instructions, I’m paying for history.

Charles Atlas was born Angelo Siciliano in 1892 and immigrated to the United States from Italy in 1903. He was the kid who got sand kicked in his face at the beach. He decided to do something about it, and got the idea for his special brand of isometric exercises while watching lions stretching at a zoo. After building his own physique, he saw a statue of the Greek god Atlas at Coney Island and decided to change his name to “Atlas” to reflect his new image. Several years later, he met entrepreneur Charles Roman and the two designed the formal exercise program (and its advertising campaign). Atlas died in 1972, but his company has continued selling the instructions to this day.

And just what do the instructions say? The core of what Atlas is teaching would now be called Isometric Contraction—exercises in which you put tension on muscles without using machines or free weights. Instead, you’re relying on opposition from other muscles. Along with isometrics are some isotonic exercises (pushing or pulling on a weight, though in this case, all the weight comes from your own body, as in push-ups). None of this is rocket science: as you increase the amount of resistance, you build muscles, and as your muscles strengthen, you further increase the amount of resistance you’re able to supply. Atlas also talks about things like breathing, posture, and proper nutrition—though some of his diet recommendations are a bit suspicious by modern standards—and he has an entire lesson on avoiding constipation.

Weight and See

Fitness experts who have seen the Atlas program typically say it’s fine as far as it goes. Of course, there are some muscle groups it doesn’t address, and aerobic fitness is basically ignored. Arguably, the use of machines or weights could yield similar results more quickly or permit someone to advance further, but for people wanting to build muscles on a budget, it’s an entirely reasonable program.

The only real problem—and the reason my arms still don’t look like Atlas’s—is that the exercises are hard. Or, perhaps I should say, they’re no easier than any other kind of exercise. Naturally, they work only if you practice them diligently over an extended period of time.

When I first got the Atlas program in the mail, I did make an honest effort to follow the instructions—for about a week. Then I gave up, due to laziness, sore arms, and a lack of time and motivation. Every once in a while I think to myself, “I should actually go all the way through the program…just to see.” Perhaps one day I will. Of course, I never, ever wanted to have the bodybuilder physique; I just don’t find that body shape appealing. And for me, written instructions and the promise that I’ll be able to beat up a bully some day are not strong motivators; if I wanted to build serious muscles, I’d probably sign up at a gym with a personal trainer. Still, for all its anachronistic campiness, the Atlas program is really a pretty good idea—good enough to keep selling by the tens of thousands more than 80 years later.

Note: This is an updated version of an article that originally appeared on Interesting Thing of the Day on May 24, 2003, and again in a slightly revised form on August 8, 2004.

“Charles Atlas” and “Dynamic-Tension” are registered trademarks of Charles Atlas Ltd.


Source: Interesting Thing of the Day