Physics Buzz

The sound of a sonic boom may produce about the same magnitude of gravitational pull as a 10-milligram weight, a new study finds. Oddly, the findings also suggest the pull is in the opposite direction of the gravitational pull generated by normal matter, meaning sound waves might fall up instead of down in Earth's gravitational field.

How do you block sound without cutting off airflow? It’s a tricky question, but new work out of Boston University shows a promising advance.

Read part I of this story here . When I set out for Orfield Labs, I expected the anechoic chamber to capture my full attention. After all, so many people come to experience the quietness that the lab had to start charging for tours, to compensate for lost productivity. As I talked with founder and president Steve Orfield about the evolution of his career and his lab, though, I started to appreciate that the chamber is a tool. And eventually I concluded that, like all tools, the true value lies in what it can do in the hands of an artisan.

Scratchy . My ultra-smooth gel pen made a distracting and mildly irritating sound that I can only describe as scratchy with each stroke. I became acutely aware of the process involved in forming each letter. I flipped a page in my memo pad to make room for more notes, but the loud, prolonged crinkling of the page only left me more distracted and further behind.

In May of 2013, an EF5 tornado—the most powerful class—devastated the city of Moore, Oklahoma and the surrounding area, killing 24 people and wounding more than 200. The tornado leveled entire blocks of houses, destroyed schools and medical buildings, and tossed cars around, wreaking havoc on the city.

Chirps, short bursts of (often annoying) high-pitched sounds, are generally a way of conveying information. Birds chirp to warn their feathered friends of impending danger. Male crickets chirp to announce their intentions to females. Smoke alarms chirp to keep you awake all night until you finally get up and change that low battery.

What is it that makes us trust one politician over another? Surely vision and values are key, but as science demonstrates, we are influenced by much subtler things as well. It turns out that our perception of political leaders and even our voting preferences can be swayed by something as simple as the acoustic properties of a leader’s voice, according to Rosario Signorello and Didier Demolin from the Laboratoire de Phonétique et Phonologie in Paris. This is the subject of the work they presented at this week’s 174th Meeting of the Acoustical Society of America in New Orleans, Louisiana.

The leverlike guitar accessory known as a whammy bar is best used to bend and distort a single note—think Jimi Hendrix's famous rendition of the Star Spangled Banner from Woodstock 1969. But it doesn't sound very nice if used when playing multiple strings simultaneously, such as when strumming a chord. To solve this problem, a researcher from the U.K. has engineered new guitar strings that respond tunefully and as a group when you use a whammy bar.

Voice-securing your ATM card. Talking to your newspaper over coffee. Projecting your voice to a room full of people using only a thin, lightweight loudspeaker that fits in your pocket. With new research published last week in the journal Nature Communications , a team of scientists from Michigan State University and Georgia Institute of Technology has opened the door to these possibilities.

Whether it’s the neighbor’s barking dogs, pounding rain, the din of traffic, or the music of your own choosing, most of us are constantly surrounded by noise. Noise is energy, so that means most of us are constantly surrounded by a relatively safe, renewable, and clean form of energy. What if we could harvest this energy?

While pursuing prey in complete darkness, horseshoe bats can zip through dense vegetation guided solely by sound. Their only protection from the raging headache—or worse—of a headlong collision is the sound waves entering their two pointy ears. New experimental research out of Virginia Tech shows that the horseshoe bat’s knack for rapidly navigating its environment is partly due to how it “wiggles” its nose and ears.

Hum a note to yourself, even just in your head. Any note will do.

Whether you’re pulling out a splinter of wood or an eyebrow hair, tweezers are the go-to tool. For these and many other situations that involve moving an object too small to grasp with human hands, a $1.49 pair of metal tweezers is good enough. However, moving an object too small to see requires a much more complicated and expensive kind of tweezers.

It’s Friday afternoon! Let’s look into the archives of physics and pretend we’re still working.

Who hasn’t wished the doctor would prescribe a week of vacation or a trip to Walt Disney World to cure an ailment? For patients with kidney stones, that might be just around the corner.

Composers usually arrange musical notes to express emotion. To set a mood. To get people dancing. To give life to inspiration. To sell records. A team of scientists at Aalto University in Finland is arranging notes for a totally different purpose—to move objects. Their work isn’t likely to top the charts, but it could bring us closer to game-changing medical technologies like lab-on-a-chip devices and new drug delivery systems. It could also be a means for sorting objects and characterizing materials.

A little over a year ago, a video of two giggling, drinking Germans started making its way around the internet. As they take sips of their beers, the giggles rise sharply in pitch, thanks to the helium that's taken the place of the CO 2  which ordinarily gives beer its carbonated bounce. Each burst of laughter sounds more ridiculous than the last, and the two lose themselves in a chain-reaction of such high-pitched hilarity that it's impossible not to be drawn in and find yourself laughing along. You can check out the video below.

The exotic cosmic objects we call black holes aren’t truly holes, and it turns out that they may not be totally black either. In an article that appears today in the journal Nature Physics , Jeff Steinhauer from the Israel Institute of Technology (Technion) outlines the strongest experimental evidence yet that energy can escape from a black hole. Professor Jeff Steinhauer in his lab. Image Credit:  Nitzan Zohar, Technion Spokesperson's Office Black holes are extremely dense areas of space defined by an event horizon, a boundary beyond which nothing that gets sucked in can escape—not even light (hence the “black” in “black hole”). Theory predicts that black holes can be the size of an atom or millions of times as massive as the sun, although smaller ones are less stable. As strange and unique as they seem, there are likely millions of black holes in the universe, including at least one at the center of each galaxy. Nearly 50 years ago, bold work by then-graduate student Jac

It's already possible to do some really extraordinary things with sound waves, like levitating small particles and manipulating them in-air  (useful for caustic chemistry reactions) but we're about to see another tool added to the sonic utility belt: spin. Scientists from Nanjing University in China have recently created a passive device that, for the first time, easily allows planar sound waves to be converted into corkscrew-shaped spiral waves without requiring elaborate geometric arrangements of sound sources.

To most of us, a heat engine is the thing that makes our car run. A refrigerator is the appliance that keeps our milk cold. Scientists, however, tend to think about things on a much more fundamental level. This week, a new paper by scientists from the Swiss Federal Institute of Technology (ETH) demonstrates how to build a heat engine and refrigerator using a couple of guitar strings and a lever. Their work, published in Physical Review Letters, could pave the way for new ways to produce energy and help us learn more about heat and energy on the microscopic scale.