Scientists can levitate stuff and make it fly around using sound

Japanese scientists have made hundreds of tiny plastic balls float around like miniature spaceships.

Today’s news from the world of Awesome Science comes from the University of Tokyo, where a team has been levitating and controlling objects using sound. Here’s the video:

As the video points out at the beginning, levitation of objects using sound has been around for a few years. If you’ve ever stood in front of a large speaker you’ll know that they can pump out what feels like quite a forceful blast of air as they vibrate - but, somewhat deceptively, that’s not quite the whole story.

Rather than physically push air out from the speaker, what you’re experiencing is a wave of compression moving through the air. The speaker compresses a packet of air, which then “rolls” through the room, with the size of the compressed air corresponding the wavelength of the sound wave. And, just like sound waves, waves that overlap each other create new waves.

To levitate something just requires creating a standing wave. Think of it like this - if you’re watching a sound wave plotted out on a graph, it’ll be rolling along, going up and down as it oscillates. A standing wave occurs when two or more waves combine to create a new wave where, as the wave oscillates, there are points where there’s no movement. They’re called nodes.

Here’s a gif to illustrate how that works. The blue and green waves are combining to create the red wave, which has those points on the central axis that aren’t moving:

(Image: Wikimedia Commons)

If a speaker outputs a standing wave, in the most basic sense it means that it won’t feel like the areas of compression - those blasts of air - are moving. The gaps between those blasts of air will be positions of neutral force, with air pressure pushing in on it from both directions. If you stick an object in there that’s light enough, and smaller that the size the gap (which will be the sound’s wavelength), the force of the air should keep it floating in a stable position.

What the Tokyo University team has done is build upon that idea, by combining sound waves in three dimensions. The video shows not just tiny little plastic balls being levitated and controlled, but also resistors, LEDs, screws, bolts, and other small items. Rhett Allain at Wired worked out that you could levitate anything both smaller than 8mm and less dense than 1,000kg/m3, which is tiny - but it does have practical applications, particularly when people are working with sterile things they want to move but can't touch, like spaceship parts or medicines.

Ian Steadman is a staff science and technology writer at the New Statesman. He is on Twitter as @iansteadman.

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Clickbaiting terror: what it’s like to write viral news after a tragedy

Does the viral news cycle callously capitalise on terrorism, or is it allowing a different audience to access important news and facts?

On a normal day, Alex* will write anywhere between five to ten articles. As a content creator for a large viral news site, they [Alex is speaking under the condition of strict anonymity, meaning their gender will remain unidentified] will churn out multiple 500-word stories on adorable animals, optical illusions, and sex. “People always want to read about sexuality, numbers of sexual partners, porn habits and orgasms,” says Alex. “What is important is making the content easily-digestible and engaging.”

Alex is so proficient at knowing which articles will perform well that they frequently “seek stories that fit a certain template”. Though the word “clickbait” conjures up images of cute cat capers, Alex says political stories that “pander to prejudices” generate a large number of page views for the site. Many viral writers know how to tap into such stories so their takes are shared widely – which explains the remarkably similar headlines atop many internet articles. “This will restore your faith in humanity,” could be one; “This one weird trick will change your life…” another. The most cliché example of this is now so widely mocked that it has fallen out of favour:

You’ll never believe what happened next.

When the world stops because of a tragedy, viral newsrooms don’t. After a terrorist attack such as this week’s Manchester Arena bombing, internet media sites do away with their usual stories. One day, their homepages will be filled with traditional clickbait (“Mum Sickened After Discovery Inside Her Daughter’s Easter Egg”, “This Man’s Blackhead Removal Technique Is A Complete And Utter Gamechanger”) and the next, their clickbait has taken a remarkably more tragic tone (“New Footage Shows Moment Explosion Took Place Inside Manchester Arena”, “Nicki Minaj, Rihanna, Bruno Mars and More React to the Manchester Bombing”).

“When a terrorist event occurs, there’s an initial vacuum for viral news,” explains Alex. Instead of getting reporters on the scene or ringing press officers like a traditional newsroom, Alex says viral news is “conversation-driven” – meaning much of it regurgitates what is said on social media. This can lead to false stories spreading. On Tuesday, multiple viral outlets reported – based on Facebook posts and tweets – that over 50 accompanied children had been led to a nearby Holiday Inn. When BuzzFeed attempted to verify this, a spokesperson for the hotel chain denied the claim.

Yet BuzzFeed is the perfect proof that viral news and serious news can coexist under the same roof. Originally famed for its clickable content, the website is now home to a serious and prominent team of investigative journalists. Yet the site has different journalists on different beats, so that someone writes about politics and someone else about lifestyle or food.

Other organisations have a different approach. Sam* works at another large viral site (not Buzzfeed) where they are responsible for writing across topics; they explains how this works:  

“One minute you're doing something about a tweet a footballer did, the next it's the trailer for a new movie, and then bam, there's a general election being called and you have to jump on it,” they say.

Yet Sam is confident that they cover tragedy correctly. Though they feel viral news previously used to disingenuously “profiteer” off terrorism with loosely related image posts, they say their current outlet works hard to cover tragic news. “It’s not a race to generate traffic,” they say, “We won't post content that we think would generate traffic while people are grieving and in a state of shock, and we're not going to clickbait the headlines to try and manipulate it into that for obvious reasons.”

Sam goes as far as to say that their viral site in fact has higher editorial standards than “some of the big papers”. Those who might find themselves disturbed to see today’s explosions alongside yesterday’s cats will do well to remember that “traditional” journalists do not always have a great reputation for covering tragedy.

At 12pm on Tuesday, Daniel Hett tweeted that over 50 journalists had contacted him since he had posted on the site that his brother, Martyn, was missing after the Manchester attack. Hett claimed two journalists had found his personal mobile phone number, and he uploaded an image of a note a Telegraph reporter had posted through his letterbox. “This cunt found my house. I still don't know if my brother is alive,” read the accompanying caption. Tragically it turned out that Martyn was among the bomber's victims.

Long-established newspapers and magazines can clearly behave just as poorly as any newly formed media company. But although they might not always follow the rules, traditional newspapers do have them. Many writers for viral news sites have no formal ethical or journalistic training, with little guidance provided by their companies, which can cause problems when tragic news breaks.

It remains to be seen whether self-policing will be enough. Though false news has been spread, many of this week’s terror-focused viral news stories do shed light on missing people or raise awareness of how people can donate blood. Many viral news sites also have gigantic Facebook followings that far outstrip those of daily newspapers – meaning they can reach more people. In this way, Sam feels their work is important. Alex, however, is less optimistic.

“My personal view is that viral news does very little to inform people at times like this and that trending reporters probably end up feeling very small about their jobs,” says Alex. “You feel limited by the scope of your flippant style and by what the public is interested in.

“You can end up feeding the most divisive impulses of an angry public if you aren’t careful about what conversations you’re prompting. People switch onto the news around events like this and traffic rises, but ironically it’s probably when trending reporters go most into their shells and into well-worn story formats. It’s not really our time or place, and to try and make it so feels childish.”

Amelia Tait is a technology and digital culture writer at the New Statesman.

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