Technology: quotes, facts and reflections - Page 8

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WonderMigration

Polynesian navigators crossed thousands of kilometres of open Pacific without compass, charts or instruments. They steered by rising and setting stars, the sun, ocean swells and seabirds, and kept track of speed and direction in their heads.

By the 1970s the old skills had almost disappeared, and some scholars argued that the Pacific islands had been settled by canoes drifting there by chance. The Polynesian Voyaging Society set out to test this with the help of Mau Piailug, a master navigator from the small island of Satawal in Micronesia, where a closely related tradition survived. In 1976 he guided the double-hulled canoe Hōkūleʻa about 4,000 kilometres from Hawaii to Tahiti without any instruments. The voyage showed that deliberate long-distance navigation was possible. Piailug went on to teach Hawaiian navigators, among them Nainoa Thompson, and traditional wayfinding has since been revived across the Pacific.

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WonderTrade

The Silk Roads were not a single road but a web of caravan and sea routes that linked China with Central Asia, India, Persia and the Mediterranean for more than 1,500 years. Along with silk and spices, they carried religions, inventions and diseases.

The name is much younger than the routes: the German geographer Ferdinand von Richthofen coined it, as Seidenstraße, in 1877. The trade grew under China's Han dynasty from the second century BC, when envoys and caravans opened paths westwards through oasis towns such as Kashgar and Samarkand, while ships linked Chinese, Indian, Arab and East African ports. Few merchants travelled the whole way; goods passed from hand to hand. Along these routes Buddhism reached China, and papermaking travelled west to the Islamic world and then to Europe. In the fourteenth century the plague is thought to have spread along them towards the Black Sea and Europe.

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WonderTrade

Shipping containers, steel boxes built to standard sizes, let cargo move from ship to lorry to train without being unpacked. Since the first container voyage in 1956, they have cut loading costs so sharply that they helped create today's global trade.

Before containers, dockworkers loaded ships one sack, crate and barrel at a time, and loading a ship could take days or weeks. The American trucking entrepreneur Malcolm McLean changed that. On 26 April 1956 his converted tanker Ideal X sailed from Newark to Houston with 58 containers on deck. McLean calculated that loading cost about 16 cents a ton, against almost six dollars for cargo loaded piece by piece. International standards for container sizes and corner fittings followed in 1968–1970, so any box could fit any crane, ship or lorry. Ports changed, many dockworkers lost their jobs, and making goods far from where they are sold became cheap.

ContainerizationRead card

WonderEngineering

The Archimedes screw lifts water with a spiral blade turning inside a tilted tube: each turn traps a pocket of water and carries it upwards. Described more than 2,200 years ago, it is still used to irrigate fields, drain land and pump sewage.

Tradition credits the Greek mathematician Archimedes of Syracuse with the invention in the third century BC, but the credit is uncertain. Similar screws may already have been used in Egypt, and the historian Stephanie Dalley has argued that the Assyrian king Sennacherib watered his gardens at Nineveh with bronze screws in the seventh century BC. A famous early use comes from the Syracusia, a giant ship built for King Hiero II of Syracuse: according to an ancient account, one man could pump out the water that collected in its hull with a screw. Run in reverse, with falling water turning it, the same device now drives small hydroelectric plants.

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WonderEngineering

The Tacoma Narrows Bridge in Washington State collapsed on 7 November 1940, four months after opening, when a wind of about 64 km/h set its light, flexible deck twisting until it tore apart. The disaster changed how engineers design long bridges against wind.

The bridge moved so much in the wind from the day it opened that locals nicknamed it Galloping Gertie. On the final morning the motion changed from up-and-down waves to a violent twisting, filmed by a local camera shop owner. No person died; a dog left in a stranded car was lost. The collapse is often blamed on resonance, but engineers now describe it as aeroelastic flutter: the twisting deck and the wind fed energy into each other. The investigation board included the aerodynamicist Theodore von Kármán. The replacement bridge, opened in 1950, used a deep, open truss that lets the wind pass through, and wind-tunnel tests became standard for long bridges.

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WonderSpace

A solar sail is a huge, ultra-thin mirror that lets a spacecraft travel on the faint push of sunlight. It needs no fuel, and the tiny push keeps adding speed for as long as light falls on it.

Light has no mass, but it carries momentum, so when it bounces off a mirror it gives it a tiny push. The idea goes back to Johannes Kepler, who noticed in the early 1600s that comet tails point away from the Sun and imagined ships sailing on a heavenly breeze. In 2010 Japan's IKAROS became the first spacecraft to use a solar sail in interplanetary space, on its way past Venus. In 2019 the Planetary Society's LightSail 2, partly funded by public donations, showed that a small satellite could raise its orbit using sunlight alone; it burned up in the atmosphere in 2022. The push is tiny, but it never runs out, so over months it adds up.

Solar sailRead card

WonderMigration

Over several thousand years, Bantu-speaking farming peoples spread from the highlands between today's Cameroon and Nigeria across most of central, eastern and southern Africa. Hundreds of related Bantu languages, including Swahili, Zulu, Shona and Kikuyu, are spoken there today.

Historians once pictured a single great 'Bantu migration'. Linguistic, archaeological and genetic evidence now points to a slower spread along many routes, roughly between 4000 BC and AD 500, with Bantu speakers reaching what is now South Africa by about AD 300. The German linguist Wilhelm Bleek coined the name Bantu in 1862 from the word for 'people' shared by many of these languages. Farming, herding and iron-working spread in different mixes from region to region, and everywhere the newcomers mixed with the people already living there. The click sounds of Zulu and Xhosa, for example, were borrowed from the Khoisan languages spoken earlier in southern Africa.

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DriveTrade

Founded in 1602, the Dutch East India Company (VOC) combined investment, shipping, military power and colonial trade to become one of history's first global corporations.

The Dutch parliament, the States General, gave the VOC a 21-year monopoly on Dutch trade east of the Cape of Good Hope, along with powers normally held by states: it could build forts, keep an army, wage war, sign treaties and mint coins. To raise money it sold shares to the public, and trading in those shares in Amsterdam made it one of the first companies with freely traded stock. From its Asian headquarters at Batavia, today's Jakarta, it dominated the spice trade, often by force: in 1621 its troops killed or expelled most of the people of the Banda Islands to control nutmeg. At its height it employed tens of thousands of people. Debt and corruption brought it down, and it was dissolved in 1799.

Dutch East India CompanyRead card

WonderArchitecture

Angkor, capital of the Khmer Empire in today's Cambodia from the ninth to the fifteenth century, was ringed by giant reservoirs, moats and canals that stored monsoon rain and moved water across an urban area of about 1,000 square kilometres.

The largest reservoirs, called barays, are vast rectangles banked with earth: the West Baray, built in the eleventh century, measures about eight kilometres by two and still holds water. Moats such as the one around Angkor Wat framed temples modelled on the sacred mountain and surrounding oceans of Hindu and Buddhist cosmology. Radar and aerial surveys published in 2007, and airborne laser scanning (lidar) that saw through the forest in 2012, revealed roads, canals and house mounds across at least 1,000 square kilometres, the largest known pre-industrial settlement. Researchers still debate how much the barays watered rice fields. Tree rings show long droughts broken by intense monsoons in the fourteenth and fifteenth centuries, which damaged the network and probably contributed to Angkor's decline.

Angkor hydraulic systemRead card

WonderEngineering

The Pont du Gard in southern France is a three-tier Roman bridge, 48.8 metres high, built to carry the aqueduct that supplied Nîmes across the Gardon River while keeping the very slight downhill slope that let water flow by gravity alone.

The aqueduct ran about 50 kilometres from a spring near Uzès to Nîmes, yet dropped only about 12.6 metres over its whole length, an average of some 25 centimetres per kilometre. The bridge's lower arches span the river, and a row of small arches on top carries the covered water channel. It is the tallest Roman aqueduct bridge still standing. Most historians date it to the first century AD, possibly the reign of Claudius. After the aqueduct fell out of use, around the sixth century, the bridge served for centuries as a road crossing, and parts of its second tier were cut away to let carts through. Napoleon III ordered a major restoration in the 1850s, and UNESCO listed it as a World Heritage Site in 1985.

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WonderBiology

The yellow slime mould Physarum polycephalum, a single-celled organism with no brain, can grow a network of tubes between scattered pieces of food that balances short routes, backup links and low cost, much as engineers try to do.

Despite its name, a slime mould is not a fungus: Physarum lives as one giant cell with many nuclei that creeps over damp logs, feeding on bacteria and fungal spores. In a 2010 study in the journal Science, a team led by Atsushi Tero of Hokkaido University placed oat flakes in the pattern of 36 cities around Tokyo and set the slime mould on the spot marking Tokyo. Bright light, which it avoids, stood in for mountains and sea. Within about a day it had linked the oats with a network that closely matched the real Tokyo rail system in efficiency, cost and resistance to breaks. The team then turned the organism's simple local rules into a mathematical model for designing networks.

Physarum polycephalumRead card

DriveSpace

On 26 September 2022, NASA's DART spacecraft deliberately crashed into Dimorphos, a small asteroid orbiting a larger one, and cut the time it takes to circle its partner by about 33 minutes. It was the first proof that an impact can change an asteroid's path.

DART, short for Double Asteroid Redirection Test, launched in November 2021 and hit Dimorphos, about 150 metres across, at roughly 6.1 kilometres per second. Neither Dimorphos nor its partner Didymos was ever a threat to Earth; the pair was chosen because a change in the small asteroid's orbit is easy to measure with telescopes. Before the impact, Dimorphos circled Didymos every 11 hours and 55 minutes. The team would have counted a change of 73 seconds as success; the actual change was about 33 minutes, partly because the impact threw off a huge plume of rock and dust that pushed the asteroid further. A small Italian satellite, LICIACube, photographed the plume, and the European Space Agency's Hera probe, launched in 2024, is due to arrive in late 2026 to study the crater.

NASA DART missionRead card

WonderSpace

NASA's Parker Solar Probe, launched in 2018, flies through the Sun's outer atmosphere, the corona. In December 2024 it passed just 6.1 million kilometres from the solar surface, closer than any spacecraft before it.

The probe is named after the astrophysicist Eugene Parker, who in 1958 predicted the solar wind, the stream of charged particles flowing out from the Sun; it was the first NASA spacecraft named after a living person. A carbon-composite heat shield about 11 centimetres thick faces the Sun and heats to around 1,000 °C, while the instruments behind it stay near room temperature. Seven flybys of Venus shrank its orbit step by step. At its closest passes it travels at about 690,000 kilometres per hour, the fastest any human-made object has gone. In 2021 it became the first spacecraft to fly through the corona. Its measurements help explain how the solar wind is launched and how solar storms can disrupt satellites and power grids.

Parker Solar ProbeRead card

WonderMigration

Starting from Taiwan more than 4,000 years ago, seafarers speaking languages of the Austronesian family settled the islands of South-East Asia and much of the Pacific, as far as Hawaii, New Zealand and Easter Island, and to the west reached Madagascar.

Most linguists, archaeologists and geneticists agree that the expansion started in Taiwan and reached the Philippines by around 2000 BC, though the newcomers mixed extensively with people already living in the islands. Sailing outrigger canoes, boats steadied by a float on one side, they carried taro, yams, pigs, dogs and chickens. From about 3,300 years ago a distinctive stamped pottery called Lapita marks their spread into the western Pacific. Navigating by stars, ocean swells and birds, Polynesian voyagers later reached Hawaii, Easter Island and finally New Zealand, around AD 1250 to 1300. About 1,500 years ago others crossed the Indian Ocean to Madagascar, which is why Malagasy is most closely related to a language of Borneo.

Austronesian expansionRead card

DriveBiography

Fazlur Rahman Khan, a Bangladeshi-American structural engineer, made very tall buildings cheaper to build with his 'tube' systems, in which a tower's outer walls work together to resist the wind. They shaped Chicago's John Hancock Center and the Sears Tower, now Willis Tower.

Before Khan, most skyscrapers relied on a rigid internal frame of steel columns and beams, and the taller they went, the more steel they needed to keep them from swaying in the wind. In Khan's framed tube, columns are set close together around the outside of the building and tied by deep beams called spandrels, so the whole outer wall acts like one stiff, hollow tube anchored in the ground. Working at the Chicago firm Skidmore, Owings & Merrill, he developed variations: the John Hancock Center (1969) braces its tube with giant diagonal X-shapes, and the Sears Tower (1973) bundles nine tubes together. Khan was born in Dhaka in 1929 and died in 1982.

Fazlur Rahman KhanRead card

DriveDesign

Isotype is a way of showing social and economic data with rows of small repeated pictures, so that people can understand it across languages and levels of schooling. It was developed in 1920s Vienna by Otto Neurath, Marie Reidemeister (later Marie Neurath) and the graphic artist Gerd Arntz.

Isotype stands for International System of Typographic Picture Education. Otto Neurath developed it in 1920s Vienna at the Social and Economic Museum, aiming to let ordinary readers, including people with little schooling, compare social and economic data at a glance. Its central rule was to never resize a single icon to show a bigger quantity; instead, a larger number was shown by repeating the same small icon more times, so a reader could count as well as compare. After Austria's political turmoil forced Neurath to flee in 1934, he continued the project first in the Netherlands and later in England. The approach's descendants are visible today in transport maps, road signs and the small repeated icons used in modern infographics.

Isotype picture languageRead card

WonderArchaeology

The Dover Bronze Age Boat, found under a road in Dover in 1992, was built about 3,500 years ago from oak planks sewn together with yew and made watertight with moss and animal fat.

Workers building the A20 road between Folkestone and Dover uncovered the boat on 28 September 1992, six metres below the surface. Waterlogged, airless ground had kept the oak from rotting. Archaeologists worked for nearly a month to lift a 9.5-metre section; the rest ran under nearby buildings and had to be left in place. The planks are held together by twisted yew stems and by wooden wedges driven through cleats, raised blocks carved out of the planks themselves. It is dated to about 1575 to 1520 BCE, which makes it one of the oldest seagoing boats known. Whether it ever crossed the Channel is still debated. It is on display in Dover Museum.

Dover Bronze Age BoatRead card

WonderEngineering

The Shushtar Historical Hydraulic System in Iran is a network of dams, bridges, tunnels, canals and mills on the Karun River, much of it built in the 3rd century CE. It watered farmland, supplied the town and drove water mills.

Tradition traces the first canals at Shushtar to the Persian king Darius the Great in the 5th century BCE, but the system's key works belong to the Sasanian Empire. The Band-e Kaisar, or Caesar's Dam, a weir about 500 metres long across the Karun, is said to have been built by Roman soldiers captured when the Sasanian king Shapur I defeated the emperor Valerian in 260 CE. It raised the river so that water could be led into canals and rock-cut tunnels, where it drove mills and fed fields before pouring down a series of falls into a basin below the town. Thirteen dams, bridges and other works operated as one system. UNESCO listed it as a World Heritage Site in 2009.

Shushtar Historical Hydraulic SystemRead card

WonderEngineering

A hypocaust was the Roman system of underfloor heating: a furnace sent hot air under a floor raised on small pillars and, in some buildings, up through hollow walls. It warmed baths and wealthy homes.

The name comes from Greek words meaning 'heated from below'. Under the floor stood rows of small brick or stone pillars, called pilae, and a furnace outside the room pushed hot air and smoke into this low space; hollow box tiles set into the walls could carry the heat upwards and out. Roman writers credited a wealthy businessman of the early 1st century BCE, Sergius Orata, with inventing heated 'hanging baths', but historians doubt he was the first to warm floors this way. The architect Vitruvius described how to build such baths late in the 1st century BCE, and the system spread across the empire, from Britain to North Africa. Keeping it going took a steady supply of fuel and enslaved workers or servants to tend the fires.

HypocaustRead card

WonderEngineering

Float glass, the flat glass in almost every modern window, is made by pouring molten glass onto a bath of molten tin. The glass spreads into an even sheet with smooth faces that need no grinding or polishing.

Before float glass, large clear sheets were made as plate glass: cast or rolled, then ground and polished on both sides, a slow and costly job. Alastair Pilkington and Kenneth Bickerstaff of Pilkington Brothers developed the new method at the firm's works in St Helens, Lancashire, between 1953 and 1957. It works because glass is lighter than tin and does not mix with it: floating on the molten metal, the glass flattens under gravity and surface tension, then cools slowly as a continuous ribbon. The company announced the process in 1959, reached profitable full-scale sales in 1960 and licensed it around the world during the 1960s, when it replaced the older methods.

Float glassRead card

DriveEngineering

The Bessemer process, patented by Henry Bessemer in 1856, made steel by blowing air through molten iron to burn off excess carbon and other impurities. It made steel cheap enough to build railways, bridges and ships.

Bessemer's converter was a large pear-shaped vessel lined with heat-resistant brick. Air blown in from below burned away carbon, silicon and manganese, and the burning itself gave off so much heat that the iron stayed molten without any added fuel. Three to five tons could be turned into steel in 10 to 20 minutes, a job that had taken at least a full day of heating, stirring and reheating. The early process could not remove phosphorus, so it worked only with scarce phosphorus-poor ores until 1878, when Sidney Gilchrist Thomas and his cousin Percy Gilchrist introduced a converter with a basic, limestone-type lining. The price of steel fell from about £40 a ton to £6–7.

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DriveEngineering

Prestressed concrete has steel cables stretched tight inside it, so the concrete is already squeezed before any load arrives. Concrete cracks easily when pulled but is very strong when squeezed, so this lets beams and bridges span farther.

In ordinary reinforced concrete, loose steel bars carry the pulling forces, but the concrete around them still cracks as it bends. Prestressing goes further. In pre-tensioning, steel strands are stretched before the concrete is poured and released once it has hardened; in post-tensioning, cables run through ducts in hardened concrete and are then pulled tight and anchored. Either way, when traffic or weight later tries to stretch the underside of a beam, it first has to cancel that built-in squeeze. The French engineer Eugène Freyssinet patented a practical method in 1928, using high-strength steel so that the squeeze would not fade over time. From the mid-20th century prestressing became standard for bridges, car parks and floor slabs, allowing longer spans and thinner sections.

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WonderTechnology

Bakelite, invented by the chemist Leo Baekeland in 1907, was the first fully synthetic plastic. Heated in a mould, it set hard for good, and because it resisted heat and did not conduct electricity it was ideal for plugs, switches, radios and telephones.

Leo Baekeland, a Belgian-born chemist living near New York, was looking for a synthetic replacement for shellac, a natural resin made by lac insects and used to coat and insulate electrical wiring. He found a way to control the reaction between two chemicals, phenol and formaldehyde, using heat and pressure. Earlier plastics such as celluloid were made from plant cellulose; Bakelite was built entirely from laboratory chemicals. It is also a thermoset: once cured, its molecules lock into a rigid network, so it cannot be melted and reshaped. On its own the resin was brittle, so makers mixed in fillers such as wood flour. By the 1920s and 1930s it was everywhere, from telephones and radio cases to jewellery and pan handles.

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WonderEngineering

Weathering steel, often known by the trade name Cor-Ten, is an alloy that forms a tight, stable layer of rust when it is left out in the weather. That layer slows further corrosion, so the steel needs no paint.

Ordinary rust flakes off and exposes fresh metal, so corrosion keeps eating inward. Weathering steels contain small amounts of copper, chromium, nickel and phosphorus, which help the rust form a dense layer, called a patina, that sticks to the surface and keeps out much of the oxygen and moisture. Its colour darkens from orange to deep brown over a few years. US Steel introduced the alloy in 1933 for railway wagons carrying coal and ore. It only works where the surface can dry out between wettings; constant damp, sea salt or water trapped in joints defeats it. The first building to leave it bare was the John Deere headquarters in Moline, Illinois, designed by Eero Saarinen and completed in 1964.

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