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Why do different countries use different mains voltages? the biggest disparity is between the usA on 110V and most of the rest of the world on 230V. America’s lower voltage goes all the way back to thomas edison, who introduced direct current (dC) mains electricity at 110V. edison’s rival nikola tesla showed that long power lines transmitted alternating current (AC) more efficiently than dC. His AC approach won out, but he stuck with edison’s 110V. But by the time electrification spread to europe early in the 20th Century, lamps had filaments that could give out more light and handle greater power loads. so the Berliner elektrizitätswerke company in Germany established 230V as the standard. 

Is it best to charge your mobile battery from empty or half-full? nickel-based batteries were blighted by the ‘memory effect’, and would lose capacity unless regularly discharged completely. Most phones nowadays have lithium batteries, and these do not suffer from the memory effect. in fact, it is good for them if you top the batteries up rather than deplete them completely. therefore, it’s best to charge your phone from half-full. 

THE TOP 5 BIGGEST HACKS IN RECENT MEMORY MACRON EMAIL LEAK Just 48 hours before the run-off poll between Emmanuel Macron and Marine Le Pen, a 9GB cache of emails from Macron’s En Marche! party was posted on PasteBin, a filesharing platform. They were spread to WikiLeaks. “The attacks were so simple and generic that it could have been practically anyone,” France’s cybersecurity chief said. BANGLADESH BANK HEIST In February 2016, hackers got the login credentials used by Bangladesh Central Bank for the international banking transfer system SWIFT. They tried to transfer $951m to accounts in Sri Lanka and the Philippines. Most transactions were flagged, but $101m was removed. A Trojan known as Dridex was used, which hides in MS Word or Excel attachments. WANNACRY ATTACK On May 12, 2017, a global ransomware attack affected more than 2,30,000 computers, including PCs in the NHS, FedEx and Deutsche Bahn. The malware was leaked from the NSA, and targeted machines running Wi...

TYPES OF HACK VIRUSES AND WORMS Most malware tends to be either a virus or a worm. The difference comes down to the software’s ability to propagate. Like their biological namesakes, computer viruses require a host body, whereas worms can spread from one machine to the next unaided. DDOS Short for distributed denial of service, a DDOS attack is basic yet effective. It works on the principle that, if a website’s DNS server can be overwhelmed by traffic requests, the site will crash. Hackers run botnets – networks of zombie computers or devices – to besiege a server from multiple fronts simultaneously. TROJANS As its name suggests, a Trojan is a form of malware that sneaks into your computer under an innocuous guise (like an email attachment). Its cargo can be any form of malware. A Trojan’s specific ability is getting in, then leaving a backdoor open for others to follow undetected. RANSOMWARE This subset of malware made the headlines for the WannaCry atta...

To kick off the ‘Summer of Mars’ events programme at the Kennedy Space Center in Florida, NASA recently unveiled an 8.5m-long concept Martian rover that wouldn’t look out of place in the Batcave. The vehicle consists of a detachable rear section housing a science laboratory, and a front section that’s equipped with radio and GPS. Sadly, it is only a concept: according to the latest information on NASA’s website, the actual rover used in the Mars 2020 mission is likely to be similar in size and appearance to Curiosity, the 3m-long rover that’s been busy exploring the Red Planet’s surface since 2012.

TEN MOST EXPENSIVE EXPERIMENTS 01 $150 Billion International Space Station (£92 billion) Weighing nearly 420 tonnes and floating 370km above the earth, the iss has been continuously occupied by astronauts from various countries since the first crew docked on 2 november 2000. 02 $20.6 Billion International Thermonuclear experimental reactor (£12.3 billion) In 2010 construction began in france on what will become the world’s largest tokamak fusion device – a magnetically confined core in which fuel will be heated to temperatures greater than 150,000,000°c. 03 $8 Billion   James Webb Space Telescope (£4.9 billion) Scheduled to launch in 2018, this telescope – a nasa project with input from the european and canadian space Agencies – will investigate how galaxies form by peering out to the farthest reaches of space. 04 $6.65 Billion  International linear collider (£4.1 billion) A planned particle accelerator even bigger than the large Hadron collide...

TEN SCIENTISTS WHO EXPERIMENTED ON THEMSELVES Max Joseph von Pettenkofer  1818–1901 in 1992, this Bavarian hygienist drank the diarrhoea of a cholera-stricken man in an attempt to demonstrate that the microbes became harmful only after incubating in the ground. He discovered that he was wrong. William J Harrington 1923–92 the American researcher in autoimmune disorders transfused blood from a patient with idiopathic thrombocytopenic purpura into himself, showing that the condition causes the body to destroy blood platelets. Horace Wells  1815–48 An American dentist in connecticut, Wells pioneered the use of nitrous oxide (laughing gas) in dentistry by having one of his own teeth extracted while under anaesthesia. John Paul Stapp 1910–99 the American researcher made a huge contribution to air-crash safety by testing the effects of rapid deceleration on the human body, strapping himself to a rocket sled braking rapidly from up to 1,000km/h. Nicolae Mino...

TEN VISIONARY SCIENCE-FICTION WRITERS Saac Asimov  1920–92 Wrote or edited more than 500 influential books Most famous for writing the Foundation series, the russian author is often considered one of the ‘Big Three’ sci-fi writers, along with Heinlein and Clarke. His science-fiction short story Nightfall was voted the best of all time. a crater on Mars is named after Asimov – the highest accolade for a sci-fi writer? Phillip K dick  1928–82 Wrote novels inspiring blade runner and total recall As well as publishing 44 novels, dick also write around 120 short stories. the american author’s works have inspired a string of hit films including blade runner, total recall and Minority Report. Harlan Ellison 1934–present Multi award-winning author and editor this American writer has published more than 1700 short stories, novellas and essays, as well as many film and tV scripts including muchlauded star trek episodes. He’s the only three-time winner of the nebula A...

TEN ENGINEERING WONDERS OF THE MODERN WORLD Jiaozhou Bay Bridge Qingdao, China Length: 26,707m The bridge across China’s Jiaozhou Bay is the main section of a complex comprising a 41.58km roadway connecting the districts of Qingdao and Huangdao. Opened in 2011, the world’s longest bridge over water cost £5.5bn to build; its construction required 10,000 workers, 4,50,000 tonnes of steel and 2.3 million m³ of concrete. Trans-Siberian railroad russia Length: 9,289km construction on the world’s longest railway line began in 1891 and, by 1916, had successfully connected moscow in the west with Vladivostock on russia’s east coast, 9,289km away. Burj Khalifa united arab emirates Height: 828m The current tallest building in the world (boasting a full 163 storeys), this iconic skyscraper took 3,30,000 cubic metres of concrete and 39,000 tones of steel to build. the tower also boasts more than 24,000 windows. Millau Viaduct France Length: 2,460m Height: 343m The world’...

TEN RARE ELEMENTS FOUND IN OUR HOME Europium symbol: eu atomic number: 63 used in nuclear reactors as well as low-energy light bulbs and tV sets. Discovered by france’s Éugene-Anatole Demarçay in 1896. Terbium symbol: tb Atomic number: 65 found in lcD screens and solid-state memory devices (including usB drives). swedish chemist carl mosander discovered the soft, malleable and ductile metal in 1843. Lanthanum symbol: la Atomic number: 57 Another of carl mosander’s discoveries, this is one of the metals used in the nickel-metal hydride (nimH) batteries found in some smartphones, laptops and electric cars. Neodymium symbol: nd atomic number: 60 neodymium makes excellent magnets and has been put to use in computer hard drives, stereo speakers and electric motors. it’s also used to colour glass. Yttrium symbol: Y atomic number: 39 yttrium is a metal that can be added to glass to make it heat- and shock-resistant; it is found in many camera lenses. Samarium...

Ten nasa technologies with earthly applications Artificial heart pumps Introduced to commercial market: 1998 Patients awaiting heart transplants can be kept alive with a left ventricular assist device (lVAD). smaller than other heart pumps and battery operated, this instrument is based on the fuel pumps used in nAsA’s rocket engines. Memory foam Introduced to commercial market: 1969 in 1966, nAsA contracted aeronautical engineer charles yost to improve aeroplane seating in the hope of providing better crash protection. He came up with memory foam, a material that could absorb high-energy impacts but also provide greater comfort by moulding itself to any object placed upon it. Scratch-resistant lenses Introduced to commercial market: 1983 these evolved from an experiment to improve water purification on spacecraft. the result was a coating that rendered spectacle lenses almost impervious to abrasion. Fire-retardant paint Introduced to commercial market: 1974 the coat...

Ten countries with highest Smartphone penetration 01 united arab emirates 73.8% of population owns a smartphone 02 South Korea 73% of population owns a smartphone 03 saudi arabia 72.8% of population owns a smartphone 04 Singapore 71.7% of population owns a smartphone 05 norway 67.5% of population owns a smartphone 06 australia 64.6% of population owns a smartphone 07 sweden 63% of population owns a smartphone 08 Hong Kong 62.8% of population owns a smartphone 09 UK 62.2% of population owns a smartphone 10 denmark 59% of population owns a smartphone

TEN CRUCIAL COMMUNICATION BREAKTHROUGHS The Alphabet When: 4000-1200BC the ability to record information was arguably most significant breakthrough in human communication after speech. sumerian cuneiform, a pictographic writing system denoting concepts and syllables, evolved around 4000Bc. it was replaced by the Phoenician alphabet comprising characters that represent single sounds. Postal Service 27BC–Ad 14 it’s thought that the Persians were the first to introduce a kind of postal service around 550Bc. But the earliest and bestdocumented evidence of such a system, enabling the public to send written messages, dates from the reign of the roman emperor Augustus. Paper Ad 105 official records credit chinese inventor cai lun with the first production of paper, although archaeological research suggests that paper was being used in the country much earlier than that. Gutenberg press 1450 for centuries, literacy and literature were restricted to religious scholars and weal...

10 SCI-FI PREDICTIONS THAT CAME TRUE TELEVISION Predicted by: Mark Twain, From the London Times of 1904, published 1898 the first television was produced in the 1920s, but mark twain had already described the telectroscope that would “make the daily doings of the globe visible to everybody”. TABLET DEVICE Predicted by: Arthur C Clarke, 2001: A Space Odyssey, published 1968 surfing the internet on a portable device was dreamed up long before the turn of the millennium. in the late 1960s, clarke gave his fictional astronauts ‘newspads’ so they could keep up to date with the goings-on back home. EARPHONES predicted by: ray bradbury, Fahrenheit 451, published 1953 though the personal stereo didn’t appear until 1977, in the early ’50s Bradbury described earphones piping in constant music and talk. SCUBA-DIVING EQUIPMENT predicted by: Jules Verne, twenty Thousand Leagues Under the Sea, published 1870 Verne described a means of breathing underwater using apparatus that, ...