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.

Jake Paul via YouTube
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We should overcome our instinct to mock Jake Paul’s school shooting video

The urge to mock the ex-Disney star diminishes the victims he speaks to and ignores the good YouTubers can do.  

It’s very “darkest timeline”. Ex-Disney star Jake Paul (brother of vlogger Logan Paul, who infamously filmed the dead body of a suicide victim) has created a 22-minute documentary about the Parkland school shooting in which he greets Florida senator Marco Rubio with the words “Hey, what’s up man?” and doesn’t mention gun control once. 

Paul – who has previously made headlines for setting fire to a swimming pool – goes on to ask the politician: “I think like a lot of people think passing laws is super easy, can you explain some of the struggles around, uh, passing laws?”

It’s hard to not immediately balk at the documentary, which was released yesterday and has since been widely mocked by the press and individual journalists. Critics note that Paul doesn’t mention gun reform within the YouTube video, and many mock his conduct towards Rubio. Others accuse the video of being an insincere PR move, particularly as Paul has previously fetishised guns on his YouTube channel – and has a tattoo of a gun on his thigh.

21-year-old Jake Paul talks and conducts himself like a child, which is what makes the video immediately jarring (“I just wanna become homies with them and just be there for them,” he says of the Parkland survivors he is about to meet). There is a vacant – almost dumb – expression on his face when he speaks with Rubio, leading the viewer to question just how much the YouTube star understands. But this is precisely the value of the video. Paul is a child talking to an audience of children – and talking to them on their terms.

YouTube doesn’t disclose the exact demographics of a YouTuber’s audience, but fan videos and Paul’s comment section reveal that most of his 14 million subscribers are young children and teens. Paul is introducing these children to a politician, and the video is edited so that Rubio’s claims don’t go unchecked – with footage of the senator being criticised by Parkland survivors playing in between shots of Paul and Rubio’s chat.

Paul (admittedly unintentionally) asks the senator questions a child might ask, such as “Is there anything that people can look forward to? Is there anything new that you’re working on?”. Although this might be jarring for adults to watch, the comment section of Paul’s video reveals it is already positively affecting his young audience.

“Definitely going to speak out now,” writes one. Another: “I shared this to my Mum and asked her to show the head teacher so everyone do that as well.” Childishness is still transparently at play – one commenter writes “Plzzz Stop the Guns… it hurts my feeling I’m crying… 1 like = 10 Pray to Florida” – but this too shows that Paul has introduced new concepts to kids previously more concerned with online pranks and viral fame.

Of course, it’s easy to see how this might be a cynical move on Paul’s part. Yet how can we demand more from YouTubers and then criticise them when they deliver it? Paul’s video is far from perfect, but engaging children in genuine discussions about current affairs is a commendable move, one far superior to his prior acts. (Paul previously caused controversy by telling a fan from Kazakhstan that he “sounds like you’re just going to blow someone up”, and his diss-track “It’s Everyday Bro” is third most disliked video on YouTube). Like it or not, Paul has an incredible influence over young people – at least he is finally using it for good.

Paul’s video has also undeniably helped at least one teen. “It’s just easier to talk about what’s going on with someone like you than a doctor or someone,” Jonathan Blank – a Parkland survivor – tells the YouTuber in the video. Later, his mother praises Paul through her tears. “It was the best therapy for my son,” she says, “You didn’t have an agenda, you cared.”

Other Parkland survivors are angry at the media’s response to the video. Kyle Kashuv – also interviewed in the documentary – has tweeted multiple times since the video’s release. “Media has the utter audacity to mock my classmates and Senator Rubio for doing the interview ON MY REQUEST AND THE REQUEST OF TWO OTHER STUDENTS,” he wrote.  

“If you mock a video where my classmates, that witnessed their friends get murdered in cold blood, are crying and putting their hearts on their sleeve, be prepared to be hit back twice as hard.”

Kashuv differs from the most famous group of Parkland survivors, as the teen supports the STOP School Violence Act over national gun reform. Yet the teen’s politics do not make his thoughts or feelings less valid, or his voice less important in the conversation. While critics note Paul spoke little of gun reform in his video (instead he suggested that schools have bullet proof glass and Instagram should flag pro-gun posts), the YouTuber later tweeted to clarify his stance.

“Gun Reform changes we need in my opinion,” he wrote. Paul went on to suggest that anyone who wants to buy a gun should be 21, go through a six month training course, and have a mental health evaluation. He also tweeted that gun shows should be banned and there should be a “30 day wait period after purchase to receive firearm”.

This isn’t to say, of course, that Paul is right, or has all the answers, or is even equipped to discuss this topic sensitively. Yet his promise to pay for busses to the March for Our Lives demonstration in Washington DC, alongside the fact he didn’t monetise his YouTube documentary, speak of someone at least trying to do some good. “We all want the same thing and that’s to make schools safe,” he says in the video. Although he gives Rubio and the STOP School Violence Act a platform, he is dismissive of their impact.

“Kind of why I wanted to make this video in the first place is to activate parents and kids within their own schools and communities, that’s the way things are going to get done the fastest. We don’t to wait for hundreds of people in Washington DC to pass the laws,” he says.

Though the description to Paul’s video was most likely written by a far-more savvy PR, it’s hard to disagree with. “I vow to be part of the solution and utilise my platform to raise awareness and action across the board, but we cannot focus on one issue, we must actively discuss and make progress on them all,” it reads.

The criticism of Paul smacks of the old media sneering at the new media, galled and appalled that a 21-year-old YouTuber would dare wade into politics and do so less than perfectly. Concerns about propriety and morality are a veil to disguise a pervasive distaste for YouTube stars. Criticisms that his suggested solutions are stupid ignore the fact that it’s not his job to reform society. It’s like having a go at Sesame Street for not criticising Theresa May.

YouTubers might not be the idols that adults wish teenagers had, but we can’t change that. What we can do is encourage viral stars to engage with important issues, and not mock them when they do so less than brilliantly. Jake Paul may not be a good person – it might even be a stretch to describe the video as “good”. But the YouTuber made an effort that should be commended, not mocked. 

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