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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Buying into broadband’s bigger picture

Reliable internet access must be viewed as a basic necessity, writes Russell Haworth, CEO of Nominet.

 

As we hurtle towards a connected future, in which the internet will underpin most aspects of our daily lives, connectivity will become a necessity and not a luxury. As a society, we need to consider the wider benefits of enabling internet connections for all and ensure no corner of the county is left out of the digital loop.

Currently, despite government incentive schemes and universal service obligations, the rollout of broadband is left largely to the market, which relies on fixed and wireless network operators justifying deployment based on their own business models. The commercial justification for broadband deployment relies on there being sufficient demand and enough people to pay for a broadband subscription. Put flippantly, are there enough people willing to pay for Netflix, or Amazon? However, rather than depending on the broad appeal of consumer services we need to think more holistically about the provision of internet services. If road building decisions followed the same approach, it would equate to only building a road if everyone living in the area bought yearly gym membership for the leisure centre at the end of the new tarmac. The business case is narrow, and overlooks the far-reaching and ultimately more impactful benefits that are available.

Internet is infrastructure as much as roads are, and could easily prove attractive to a wider range of companies investing in digital technology who stand to gain from internet-enabled communities. Health services are one of the most compelling business cases for internet connectivity, especially in remote, rural communities that are often in the “final five per cent” or suffering with below average internet speeds. Super-fast broadband, defined as 30 Mbps, is now available to 89 per cent of UK homes, but only 59 per cent of rural dwellings can access these speeds.

We mustn’t assume this is a minority; rural areas make up 85 per cent of English land and almost ten million people (almost a fifth of the population) live in rural communities. This figure is rising, and ageing ‒ on average, 23.5 per cent of the rural population is over 65 compared to 16.3 per cent in urban areas ‒ and this presents complicated healthcare challenges for a NHS already struggling to meet demand. It goes without saying that accessibility is an issue: only 80 per cent of rural residents live within 4km of a GP’s surgery compared to 98 per cent of the urban population.

While the NHS may not have the resources to build more surgeries and hospitals, robust broadband connections in these areas would enable them to roll out telehealth options and empower their patients with healthcare monitoring apps and diagnostic tools. This would lower demand on face-to-face services and could improve the health of people in remote areas; a compelling business case for broadband.

We can’t afford to rely on “one business case to rule them all” when it comes to internet connectivity – the needs run far beyond Netflix and Spotify, and the long-term, economic and social benefits are vast. It’s time to shift our thinking, considering internet connectivity as essential infrastructure and invest in it accordingly, especially when it comes to the needs of the remote, rural areas of the country.

Russell Haworth joined Nominet as CEO in 2015. He leads the organisation as it develops its core registry business, explores the potential of new technologies in the global internet sector, and delivers on its commitment to ensuring the internet is a force for good.

This article was taken from a New Statesman roundtable supplement "The Internet as Infrastructure: Why rural connectivity is crucial to the UK’s success"

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