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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The art of the YouTube Poop

What are YouTube Poops and why do we need them now, more than ever?

“The world today doesn't make sense, so why should I paint pictures that do?”

So, allegedly, said Pablo Picasso in a shrewd attempt to justify his love of putting noses where noses don’t actually go. It is imperative that you now hold this profound quotation firmly in your mind whilst you watch this four minutes and 57 second long clip of Arthur – the cartoon aardvark – being tormented by squirrels.

What you have just seen is an example of the art form primarily known as “YouTube Poop” (YTP). Beginning in the early Noughties, this cultural movement is characterised by confusing and shocking edits of Saturday-morning cartoons, video games, and viral videos. Though the Tens have seen the genre decline in popularity, the YTP is, nonetheless, one of the defining innovations of our era.

Those in the Poop community don’t actually like being labelled as artists, as one Yale student found out when he attempted to define them as such on the University’s technology blog. Though they have been compared to Dadaism, YTPs are more vile, violent, and most importantly, nonsensical than most artworks, but this is precisely why they are an asset to our age. In a world where – sorry Pablo, you got nothing on us – absolutely zero things makes sense, it is time for the YTP to have a comeback.

Despite its seeming randomness, the world of YTP is not without its rules. “Poopisms” are the common techniques and tricks used in videos to ensure they qualify as a true Poop. They include “stutter loops” (the repetition of clips over and over), “staredowns” (freezing the frame on a particular facial expression), and the questionably-named “ear rape” (suddenly increasing the volume to shock the viewer). One of the most humorous techniques is “sentence mixing”: forcing characters to say new sentences by cutting and splicing things they have said.

There are also firm rules about what not to do. Panning across a clip without adding another Poopism at the same time is considered boring, whilst using your own voice to dub clips is seen as amateur. By far the biggest barrier that Poopers* face in creating their videos, however, is the law.

Despite what many eight-year-olds on YouTube think, declaring that something is a “parody” in the description of a video does not make it exempt from copyright laws. The video below – regarded by at least two commenters as “the best YouTube Poop” ever – is missing audio 20 minutes in, as the creator was hit by a copyright claim.

Yet even the iron fist of the law cannot truly stop Poopers, who are still going (relatively) strong after the first YTP was created in 2004. YouTube Poops now even have their own Wikipedia page, as well as a page on TV Tropes and a WikiHow guide on how to create them, and for good measure, avoid them.

YouTube Poops have therefore undoubtedly secured their place in history, and whilst you might wander into a comment section to declare “What have I just watched?”, remember that Pablo Picasso once said: “The purpose of art is washing the dust of daily life off our souls.” He almost definitely wasn’t talking about “You are a Sad Strange Little Man” by cartoonlover98, but still.

* The term “Poopists” was rejected by the community for being “too arty”.

 

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