Technik
40 cards from across every topic, each citing a source. Tap one to open it in the feed.
- A '3-nanometre chip' has no part that measures 3 nanometres.
The number once meant the length of the transistor gate. Today it is a marketing name for a new generation with more …
- A 2,000-year-old computer made of bronze.
In 1901, sponge divers pulled a corroded bronze device from a shipwreck off the Greek island of Antikythera. Built in …
- Germany's first railway ran just six kilometres.
On 7 December 1835, the locomotive "Adler" pulled the first train from Nuremberg to Fürth: about 6 kilometres in …
- How Bluetooth switches channels 1,600 times a second.
Bluetooth uses the 2.4 GHz band, the same as Wi-Fi and microwave ovens. To avoid drowning, it splits the band into 79 …
- How Egyptians dragged multi-tonne stones across the desert.
The blocks of the Great Pyramid weigh over two tonnes on average and were hauled on wooden sledges. A wall painting in …
- How Enigma encrypted, and which part gave it away.
With every keypress, current flowed through a plugboard, three rotating rotors and a reflector, then back, lighting up …
- How Gutenberg's press worked, and what was actually new.
Movable type already existed in China and Korea. Gutenberg's trick, around 1440, was the hand mould: a steel punch …
- How James Watt saved the steam engine with a side room.
The Newcomen engine of 1712 cooled the entire cylinder with water on every stroke to condense the steam, then heated it …
- How Morse code works and why E is a single dot.
Morse code uses short and long signals: a dash lasts three dots, letters are separated by a gap of three dots, words by …
- How Roman aqueducts moved water without pumps.
An aqueduct is essentially a channel many kilometres long with a tiny gradient: the line to Nîmes drops only 12.6 …
- How a machine takes over what two kidneys do.
Blood flows along a semipermeable membrane with a rinsing fluid running the other way on the far side. Dissolved …
- How a medieval trebuchet hurled stones 300 metres.
A counterweight trebuchet is a lever on an axle: the short arm carries a box holding several tonnes of stones or earth …
- How a nuclear plant makes electricity: with a steam engine.
In the reactor, uranium nuclei split and heat a coolant, usually water. That makes steam, directly or through a heat …
- How a pocket watch solved the longitude problem.
Latitude could be read from the Sun's height, longitude couldn't: you need the time at your home port. Since Earth …
- How an LED glows without getting hot.
An incandescent bulb heats a tungsten wire to about 2,500 °C; only around 5 % of the energy becomes light, the rest is …
- How early radio put speech onto a wave.
A transmitter produces a steady carrier wave, say 1,000 kilohertz. In AM radio the microphone signal varies the …
- How headphones erase noise by producing more sound.
A microphone on the headphone measures outside noise. A chip calculates what part would reach your ear and plays …
- How to read a scraped-off text after 800 years.
Parchment was expensive, so old writing was washed off and new text written over it. The Archimedes Palimpsest, copied …
- How to type tens of thousands of Chinese characters with 26 keys.
You type the romanisation pinyin, say "ma", and the system lists every character with that pronunciation; you pick one …
- How your phone battery stores power: as migrating ions.
A lithium-ion battery has two electrodes, graphite and a metal oxide, separated by an electrolyte. While charging …
- How your phone turns four timestamps into a location.
GPS satellites orbit at about 20,180 km and constantly broadcast their position and the exact time. Your receiver …
- How your smoke detector sees smoke without having an eye.
Inside sits a dark chamber with an LED and a photodiode set at an angle to each other. In clean air the light beam …
- One disaster ended the airship era in 34 seconds.
On 6 May 1937, the airship "Hindenburg" caught fire while landing at Lakehurst, New Jersey, and burned in about half a …
- One machine that replaced eight spinners at once.
Around 1764, the weaver James Hargreaves in Lancashire built the spinning jenny: a wheel that drove eight spindles …
- The "red telephone" was never a telephone.
After the Cuban Missile Crisis, the USA and Soviet Union set up the hotline in 1963. It consisted of teleprinters …
- The Eiffel Tower was due to be scrapped in 1909.
Built from 28 January 1887 to 31 March 1889, the 300-metre tower was only a World's Fair attraction, scheduled for …
- The first Atlantic cable died after three weeks.
In August 1858, a cable linked Ireland with Newfoundland. A greeting from Queen Victoria to President Buchanan took …
- The first internet message was two letters long.
On 29 October 1969, student Charley Kline at UCLA typed "LOGIN" to a computer at the Stanford Research Institute, about …
- The first satellite was a beeping metal ball.
On 4 October 1957, the Soviet Union launched Sputnik 1: a polished sphere 58 centimetres across, weighing 83.6 …
- The tin can existed 45 years before the can opener.
In 1810 Peter Durand patented the tin can in England; Nicolas Appert had just developed preserving food by heating. The …
- The word "robot" was invented in Prague in 1920.
Karel Čapek's 1920 play R.U.R. ("Rossum's Universal Robots") gave the world the word; it premiered on 2 January 1921 in …
- Why Roman concrete still stands after 2,000 years.
The Pantheon in Rome has carried an unreinforced concrete dome 43 metres across since the year 125. In 2023, an MIT …
- Why propellers look like bent bananas in phone photos.
Your phone's sensor doesn't capture the image all at once but line by line from top to bottom. If something moves fast …
- Why solar cells can never use 100 percent of the light.
A silicon cell only uses photons with energy above its band gap; red and infrared photons are wasted. Blue photons …
- Why there's an @ in your email address.
In 1971, programmer Ray Tomlinson sent the first email between two ARPANET computers standing side by side. He needed a …
- Why trains used to stop dead at the Spanish border.
About 60% of the world's railways use standard gauge, 1,435 mm, the width of George Stephenson's early lines in …
- Why we do things because we've always done them.
Path dependence means early decisions lock in later ones, even when better alternatives exist. The 1,435-millimetre …
- Why your Wi-Fi crawls in the basement.
Wi-Fi mostly uses 2.4 GHz or 5 GHz. The lower frequency has longer waves, passes through walls better and reaches …
- Why your phone ignores gloves but feels wet fingers.
Modern displays are capacitive touchscreens: beneath the glass lies a grid of transparent electrodes that maintains a …
- Without Einstein, your sat-nav would drift 10 km per day.
GPS satellites carry atomic clocks and orbit at about 14,000 km/h, 20,000 km up. Their speed makes the clocks run …