In the early 20th century, Serbian inventor Nikola Tesla dreamed of pulling limitless free electricity from the air. He was thinking on a vast scale, effectively looking at the Earth and upper atmosphere as two ends of a giant battery. His dreams were never realised, but the promise of air derived electricity - hygroelectricity - is capturing researchers' imaginations again. The difference: they're not thinking big, but very, very small.
In May, a team at the University of Massachusetts (UMass) Amherst published a paper declaring it had successfully generated a small but continuous electric current from humidity in the air. It's a claim that will probably raise a few eyebrows, and when the team made the discovery that inspired this new research in 2018, it did.
"To be frank, it was an accident," said the study's lead author, Prof Jun Yao. "We were actually interested in making a simple sensor for humidity in the air. But the student who was working on that forgot to plug in the power."
The UMass Amherst researchers were surprised to find that the device, which comprised an array of microscopic tubes, or nanowires, was producing an electrical signal regardless.
Each nanowire was less than one-thousandth the diameter of a human hair, wide enough that an airborne water molecule could enter, but so narrow it would bump around inside the tube. Each bump, the team realised, lent the material a small charge, and as the frequency of bumps increased, one end of the tube became differently charged from the other.
"So it's really like a battery," said Yao. "You have a positive pull and a negative pull, and when you connect them the charge is going to flow."
この記事は The Guardian Weekly の July 07, 2023 版に掲載されています。
7 日間の Magzter GOLD 無料トライアルを開始して、何千もの厳選されたプレミアム ストーリー、9,000 以上の雑誌や新聞にアクセスしてください。
すでに購読者です ? サインイン
この記事は The Guardian Weekly の July 07, 2023 版に掲載されています。
7 日間の Magzter GOLD 無料トライアルを開始して、何千もの厳選されたプレミアム ストーリー、9,000 以上の雑誌や新聞にアクセスしてください。
すでに購読者です? サインイン
If kids get protected from online harm, how about the rest of us?
The Australian government has proposed a ban on social media for all citizens under 16.
'It's not drought - it's looting'
Spain is increasingly either parched or flooded - and one group is profiting from these extremes: the thirsty multinational companies forcing angry citizens to pay for water in bottles.
Life in the grey Zone
Neonatal care has advanced so far that babies born as early as 21 weeks have survived. But is this type of care always the right thing to do?
Out of tune? Band Aid under fire for Africa tropes as it turns 40
Forty years ago this month, a group of pop stars gathered at a west London studio to record a single that would raise millions, inspire further starry projects, and ultimately change charity fundraising in the UK.
Deaths shine spotlight on risks of drinking on party trail
Vang Vieng is an unlikely party hub. Surrounded by striking limestone mountains and caves in central Laos, it morphed from a small farming town to a hedonistic tourist destination in the early 2000s.
Different strokes My strange and emotional week with an AI pet
Moflin can develop a personality and build a rapport with its owner - and doesn't need food or exercise. But is it comforting or alienating?
Strike zone Waking up to the rising threat of lightning
When the Barbados National Archives, home to one of the world's most significant collections of documents from the transatlantic slave trade, reported in June that it had been struck by lightning, it received sympathy and offers of support locally and internationally.
Cheap pints and sticky carpets: the old-school pub is back
In the Palm Tree pub, east London, barman Alf is taking only cash at the rattling 1960s till.
Brain gain Can a radical tax scheme convince the country's brightest to stay?
In the autumn of 2018, I moved to Lisbon for a month-long course at the Universidade .de Lisboa.
Fear and sympathy in small town divided over asylum camp
A year after anti-immigration riots, a site for asylum seekers faces hostility while some locals try to help new arrivals
