Alltag
85 cards from across every topic, each citing a source. Tap one to open it in the feed.
- 21 days to form a habit? The study says otherwise.
In 2010 Phillippa Lally tracked 96 people who repeated a new routine daily, such as drinking a glass of water with …
- 24 jams drew more shoppers, 6 jams sold more.
In 2000 Iyengar and Lepper alternated a tasting table of 6 and 24 jams in a supermarket. The large table drew 60 …
- A 5,300-year-old murder case with 61 tattoos.
On 19 September 1991, hikers found a glacier mummy at 3,210 metres in the Ötztal Alps. Ötzi lived around 3300 BC, was …
- A budget in three numbers you can actually remember.
Split your net income into three buckets: 50% for needs like rent, groceries and insurance, 30% for wants like …
- A free Coke sold almost twice as many raffle tickets.
In 1971 Dennis Regan had participants rate pictures alongside a supposed fellow participant. During a break he returned …
- A kettle is loudest just before it goes quiet.
At the bottom the water reaches 100 degrees while the top is still at 70. Steam bubbles form there, rise into cooler …
- A thermos works because there's nothing inside it.
Heat travels three ways: conduction, convection and radiation. A thermos has two walls with a vacuum between them. With …
- An hour used to be longer in summer than in winter.
Until the late Middle Ages, Europeans divided the time between sunrise and sunset into twelve hours, however long the …
- An induction hob heats the pan, not the surface.
Beneath the glass sits a copper coil carrying alternating current at roughly 25 to 50 kilohertz. Its magnetic field …
- Assembled it yourself? Suddenly it's worth 63 percent more.
Norton, Mochon and Ariely had people either assemble furniture themselves or inspect pre-built pieces. The builders …
- At Christmas 1914 soldiers left the trenches to shake hands.
Along several sections of the Western Front at Christmas 1914, German and British soldiers spontaneously stopped …
- Bread crust, steak and coffee owe their flavour to the same reaction.
From roughly 140 to 165 °C, amino acids react with sugars into hundreds of new flavour and colour compounds: the …
- Counting seconds tells you how far away the storm is.
Sound moves through 20 °C air at about 343 metres per second; light arrives practically instantly. When you see …
- Every banana is slightly radioactive.
Bananas are rich in potassium, and about 0.012 % of it is the radioactive isotope potassium-40. One banana delivers …
- Helium doesn't raise your pitch. Seriously.
With helium in your lungs, your vocal cords vibrate at exactly the same rate, so the pitch stays put. But sound travels …
- How a QR code still works with a hole in the middle.
A QR code stores not just your data but Reed-Solomon check data too – like the check digits of an IBAN, only far more …
- How a card payment travels halfway around the world in a second.
Typing your PIN starts a relay race: the terminal sends amount and card data to the merchant's service provider …
- How a hook-and-loop fastener holds – copied from an annoying plant.
In 1941 Swiss engineer George de Mestral came home from hunting covered in burdock burrs. Under a microscope he saw …
- How a second factor makes stolen passwords worthless.
A password is something you know. A second factor is something you have, like your phone with an authenticator app, or …
- How an IBAN catches a typo before money moves.
Digits three and four of an IBAN are check digits. To verify, the IBAN is rearranged, letters become numbers and the …
- 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 baking powder puffs up a cake, and why baking soda alone can't.
Baking powder is sodium bicarbonate plus a dry acid plus a little starch against moisture. As soon as liquid joins …
- 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 one pronoun calms your head before a performance.
In your head, talk about the situation not as "I" but using your own name or "you". In 2014 Ethan Kross and colleagues …
- How one word for your feeling calms the amygdala.
Lieberman and colleagues showed in a 2007 brain-imaging study: people who see a fearful face and label it with the word …
- How to build an emergency fund before you invest.
Add up your fixed monthly costs: rent, food, insurance, transport. Multiply the total by three to six. That's your …
- How to find your forgotten subscriptions in 20 minutes.
Download your last three months of account transactions and filter for recurring amounts to the same payee. Write down …
- How to remember intentions instead of thinking about them.
Remembering to do something later works far better when an external event supplies the trigger than when you have to …
- How to reverse a wrong direct debit with one click.
With a SEPA direct debit, the payee pulls money from your account because you gave them a mandate. In return, you can …
- How to soften rock-hard avocados in two days.
Bananas, apples, tomatoes and avocados keep ripening after harvest because they release the gas ethylene, a plant …
- How to use your favourite podcast as exercise bait.
In 2014 Milkman, Minson and Volpp gave students gripping audiobooks they could only listen to at the gym. That group …
- 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 …
- If your neighbour can hear your music, it is too loud.
In-ear headphones at full volume can exceed 100 dB – as loud as a circular saw, right at the eardrum. The WHO advises …
- In 1582, ten days simply vanished from the calendar.
The Julian calendar ran about 11 minutes too long per year; by 1582 the spring equinox had drifted ten days. Pope …
- Jeans weren't patented as trousers, but as a rivet.
Tailor Jacob Davis in Nevada reinforced work trousers with copper rivets at the pocket corners, where they always tore. …
- More witnesses, less help – usually.
A 2011 meta-analysis of 105 studies confirms the bystander effect: in groups, everyone feels less responsible, and …
- Multitasking doesn’t exist – only rapid switching.
The brain doesn’t process two demanding tasks in parallel; it toggles between them. Every switch costs time to reload …
- Nearly half your day, you're thinking about something else.
In 2010 Killingsworth and Gilbert sampled 2,250 adults at random moments via an app. In 46.9 percent of samples their …
- No English speaker understands the German 'Handy'.
'Handy' is a pseudo-anglicism: it sounds English, but English never used it for a mobile phone. Brits say mobile …
- No straw on Earth works beyond ten metres in length.
When you suck, you create no pull, only low pressure: the air pressure outside pushes the drink upward. That pressure …
- Nobody noticed your embarrassing T-shirt. Really.
In 2000 Gilovich had students wear a Barry Manilow shirt into a seminar room. They estimated about half the people …
- Nothing matters as much as it seems while you consider it.
In 1998 Schkade and Kahneman asked whether people in California are happier. Respondents in the Midwest and in …
- On Everest, water boils at about 70 degrees.
Water boils when its vapour pressure matches the air pressure. At sea level that happens at 100 °C. The higher you …
- Physics still isn't sure why ice is slippery.
The textbook story, that the pressure of a skate blade melts the ice, was refuted in 1939: it would make skating below …
- Pick your own ticket, charge four times as much. Same odds.
In 1975 Ellen Langer let office workers either choose a lottery ticket or receive one at random. Those who chose …
- Planes fly because their wings shove air downward.
A wing is tilted slightly and curved on top. The oncoming air follows the surface and is deflected downward behind the …
- Properly stored honey keeps indefinitely.
Honey holds only about 18 percent water; the rest is sugar that pulls water out of any microbe. Add a pH of around 3.9 …
- QWERTY was not designed to slow you down.
The popular story says the keys were deliberately spread awkwardly so typists would go slower and the typebars would …
- Roman toilet paper: a sponge on a stick.
In Roman latrines, people sat side by side on long stone benches with holes. For cleaning they used a xylospongium, a …
- Soap cleans because its molecules have two faces.
A soap molecule has a water-loving head and a long fat-loving tail. In water, the tails burrow into grease droplets …
- Stainless steel doesn't rust because it heals itself.
Steel counts as stainless once it contains at least 10.5 percent chromium. The chromium reacts with oxygen in the air …
- Tally sticks: medieval receipts that burned down Parliament.
Before paper was common, debts were cut as notches into a wooden stick, which was then split lengthwise: creditor and …
- Ten tonnes of air are resting on your desk.
Standard air pressure at sea level is 101,325 pascals, about 1 kilogram of force per square centimetre. On one square …
- The "first floor" is downstairs in New York and upstairs in London.
In Europe, most Commonwealth countries and much of Latin America the ground floor is 0 and the "first floor" is one …
- The electrons in your cable crawl slower than a snail.
With one ampere flowing through a 2-millimetre copper wire, the electrons drift on average only 23 micrometres per …
- The expensive products sit exactly where you're looking.
Supermarkets plan every shelf with so-called planograms. At eye level, roughly 120 to 160 cm, sit the highest-margin …
- The first text message was sent from a computer.
On 3 December 1992, engineer Neil Papworth typed "Merry Christmas" on a PC and sent it over the Vodafone network to a …
- The metal spoon isn't colder than the wooden one.
Both sit at room temperature, about 20 degrees. But your skin doesn't measure temperature – it measures how quickly …
- The most expensive loan is the one you never applied for.
An overdraft is a pre-approved facility on your current account. You sign nothing; the balance simply goes negative. …
- The same mug is worth twice as much once it's yours.
In 1990 Kahneman, Knetsch and Thaler handed mugs to half the participants. Owners demanded about $7 to sell, buyers …
- The siren never changes its pitch. You just hear it differently.
As an ambulance approaches, it squeezes its sound waves together: they arrive more densely and the tone sounds higher. …
- The sky is blue because air loves to scatter blue.
Air molecules are far smaller than light waves and scatter short wavelengths much more than long ones, proportional to …
- 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 …
- Two global institutions began as regulars' tables in a coffee house.
London's first coffee house opened in 1652; by 1675 England had over 3,000. A penny at the door bought newspapers and …
- What a kilowatt-hour really is, in muscle power.
One kilowatt-hour is 3.6 million joules. That lifts a one-tonne car about 370 metres, heats roughly 10 litres of water …
- Why a 10-minute nap works better than 30 minutes.
In 2006 Brooks and Lack compared naps of 5, 10, 20 and 30 minutes. The 10-minute nap produced the strongest and …
- Why every town once kept its own time.
Until the 19th century, each town set its clocks by local solar noon: London and Bristol differed by about 10 minutes. …
- 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 rich merchants were nicknamed 'pepper sacks'.
In the Middle Ages, pepper travelled thousands of kilometres from India to Europe, through many hands and customs …
- Why road salt melts ice while staying ice cold.
Dissolved particles disrupt the ice crystal lattice, so salt water freezes below 0 °C. Salt on ice dissolves into the …
- Why spinning makes you dizzy only once you stop.
The fluid in your inner ear's semicircular canals has inertia. When you start spinning, it lags behind and bends …
- Why the microwave heats your soup but not the plate.
A microwave oven emits radio waves at 2.45 GHz. Water molecules are electric dipoles, so they flip back and forth about …
- Why you recall a list's start and end, not its middle.
Learn a list of 15 words and you'll recall the first and last ones best. The first ones you had time to rehearse, so …
- 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 favourite music comes from your youth.
Ask older people for life memories and they cluster strikingly between roughly ages 10 and 30. The same pattern shows …
- 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 …
- Yawning doesn't add oxygen. Here's why you still do it.
The textbook story is refuted: breathing air richer in oxygen does not reduce how often you yawn. Today's leading …
- You come up with far more ideas while walking.
In 2014 Oppezzo and Schwartz had people generate unusual uses for everyday objects while sitting or walking. Walking – …
- You cross time zones every week – without a plane.
Social jet lag, a term coined by chronobiologist Till Roenneberg, is the gap between your mid-sleep on workdays and on …
- You owe the microwave oven to a melted chocolate bar.
In 1945, engineer Percy Spencer at Raytheon was working on magnetrons, the transmitters in radar sets. He noticed a …
- You sign contracts every day without signing anything.
A contract forms through offer and acceptance: the baker offers the roll, you take it and pay, done. Written form is …
- You wash your hands – then touch your phone.
A 2020 review of 56 studies found bacteria on practically every smartphone, including staphylococci and E. coli. The …
- Your 4 p.m. coffee is still half there at midnight.
Caffeine blocks adenosine receptors – adenosine is the signal that builds up sleep pressure across the day. Its …
- Your first years were erased, not never recorded.
Most adults date their earliest memory to age three or four; before about 3.5 years almost nothing survives. Back in …
- Your fridge doesn't make cold. It moves heat.
A compressor squeezes a refrigerant, which gets hot and dumps that heat into your kitchen through the coils on the …