Topics

Science

1,604 cards. Each one is a 40-second story with a five-minute read behind it. Page 20 of 27.

1141. Elephants carry a fetus for 23 months; jumping mice need just 18 daysA fetal stage lets animals give birth to young that are already well developed, at a real cost to the mother. How long that takes varies enormously: placental mammals carry young …
1142. Sitting on a toilet is a 19th-century novelty; most people squatThe Western sit-down toilet feels universal, but it only spread in the 19th century with indoor plumbing. Most of the world, including much of Africa, Asia and the Middle East, us…
1143. A human embryo spends its first week dividing without growing at allAfter fertilisation, the single-celled zygote splits again and again inside a protective protein shell, yet a week later the embryo is no bigger than when it started. Only when it…
1144. A plant stays partly embryonic its whole life; an animal never doesBy the time an animal is born or hatches, it already has every body part it will ever have; from then on it simply grows and matures. A plant never finishes. Meristems at its tips…
1145. Your stomach coats itself in slime to survive its own acidGastric juice is built to dismantle protein, and the stomach wall is made of protein. To keep from digesting itself, the stomach secretes mucus and bicarbonate that form a slipper…
1146. The Amazon molly has no males, so it borrows sperm from a relativeThe Amazon molly is an all-female fish. To reproduce it needs sperm from a related species, the sailfin molly, but only to trigger development; the father's genes are discarded. I…
1147. Biologists define male and female by one thing: the size of sex cellsIn biology, male and female are defined not by chromosomes or anatomy but by gamete size. By convention, organisms producing small sex cells, sperm, are male; those making large o…
1148. Whale calves arrive tail first so they don't drown during birthWhales, dolphins and porpoises usually give birth tail first, which lowers the risk of the calf drowning before it is fully out; the mother then nudges it up to breathe. Across th…
1149. All the sugar in your bloodstream adds up to about one teaspoonA healthy 75-kilogram adult with five litres of blood carries only about 5 grams of glucose in circulation, roughly a teaspoon of sugar. The body defends that tiny amount relentle…
1150. Your breathing is steered mostly by carbon dioxide, not oxygenIt feels as if we breathe to get oxygen, and we do, but the brain mostly sets the pace by tracking carbon dioxide. Sensors in the medulla respond to the acidity that CO2 creates i…
1151. Labour pain comes in two kinds, and only one yields easily to opioidsAbout 132 million babies were born worldwide in 2023. For the mothers, labour pain is not one sensation but two: a deep, visceral ache as the cervix stretches open, and a sharper …
1152. A mimosa kept in darkness proved in 1729 that living things keep timeIn 1729 the French scientist Jean-Jacques d'Ortous de Mairan shut a Mimosa pudica plant away from daylight. Its leaves kept opening and closing on a roughly 24-hour schedule anywa…
1153. Beetles, lotus leaves and your fingernails all have a 'cuticle''Cuticle' names a tough, flexible, non-mineral outer layer, and nature has invented it many times over. The skin fold at the base of a fingernail, the armour of an insect, the wax…
1154. Every plant lives two lives, and pollen is one of themPlants cycle between two distinct bodies: one carrying a single set of chromosomes, the other carrying two. In mosses the single-set generation is the green plant you see. In flow…
1155. Men make about 20 times more testosterone daily, yet women are more sensitiveTestosterone is often cast as the male hormone, and adult men do carry seven to eight times the levels found in women, producing about 20 times as much each day. But women's bodie…
1156. DNA was found in 1869 and ignored as the stuff of heredity for decadesFriedrich Miescher pulled a strange substance out of cell nuclei at Tübingen in 1869 and called it nuclein. Seventy-five years passed before an experiment showed it carried geneti…
1157. The so-called love hormone is really a Greek word for swift birthOxytocin gets called the cuddle or love hormone, but its name comes from Greek words meaning swift childbirth. It was discovered as a chemical that makes the womb contract. Only l…
1158. A startled pronghorn warns its herd with a smell like buttered popcornWhen a pronghorn antelope senses danger, it flares the white hair on its rump and exposes two glands that release a scent people have likened to buttered popcorn. Humans can smell…
1159. Plants run on hormones without a single gland to make themAnimals make hormones in dedicated glands. Plants have none, yet almost any plant cell can produce the signalling chemicals that control growth, flowering, defence and dormancy. T…
1160. The protein figure on a food label is really a nitrogen countNobody weighs the protein in your breakfast cereal directly. Standard tests measure the total nitrogen in a sample and multiply it by 6.25, since proteins average about 16 percent…
1161. Starch stiffened Elizabethan ruffs long before it thickened modern gravyThe word starch comes from a Germanic root meaning strong or stiff, and German Stärke still means both strength and starch. For centuries its big uses were stiffening linen and si…
1162. Steroids take their name from a waxy substance first found in gallstonesTestosterone, cortisol, cholesterol and the anti-inflammatory drug dexamethasone look nothing alike in what they do, yet all share the same skeleton of four fused carbon rings. Th…
1163. A young German pharmacist pulled the first drug molecule out of a plantIn 1804 Friedrich Sertürner extracted a pure substance from opium and named it morphium, after Morpheus, the Greek god of dreams, because it sent people to sleep. It is thought to…
1164. A gap narrower than a virus proved that brain cells talk chemicallyInto the twentieth century, most scientists pictured nerve cells passing signals electrically, like wires spliced together. Then Santiago Ramón y Cajal spotted a gap of just 20 to…
1165. Tobacco makes nicotine to poison the insects that try to eat itNicotine evolved as a plant's chemical weapon: to insects it is a potent neurotoxin. Farmers sprayed tobacco extracts on crops from at least 1690, and Americans bought it as a gar…
1166. For four years the word lactose belonged to an entirely different sugarMilk sugar got its name from Jean-Baptiste Dumas in 1843. Then in 1856 Louis Pasteur crystallised one of its building blocks and called that lactose too. Marcellin Berthelot untan…
1167. A French committee vote in 1923 finally gave fats and waxes one nameFor a century chemists argued over lipoid, lipin and lipide, each author using the terms differently. On 3 July 1923 an international commission of French biological chemists unan…
1168. Every human skin tone mixes its two main pigments in nearly the same ratioPale or deep brown, human skin holds roughly three parts dark eumelanin to one part reddish pheomelanin, around 74 to 26 percent. What varies from person to person is the total qu…
1169. Soiled bandages and a kitchen blender helped prove genes are made of DNAIn 1869 Friedrich Miescher scraped cells off pus-soaked bandages and found an odd phosphorus-rich substance he called nuclein. Decades later, Alfred Hershey and Martha Chase used …
1170. Every estrogen in your body starts life as an androgen like testosteroneThe so-called female hormone is built from male ones. An enzyme called aromatase converts testosterone and androstenedione into estrogens, and in both sexes androgens actually cir…
1171. Your brain cannot burn fat directly, so the body turns part of it into sugarA gram of fat holds about nine food calories, more than twice as much as carbohydrate, which is why animals store energy this way. But the brain cannot run on fatty acids. When it…
1172. Why natural fatty acids almost always have an even number of carbonsCells build fatty acids two carbon atoms at a time, adding pairs in a repeating cycle, so nearly every natural chain ends up even-numbered. The kinks in those chains matter as muc…
1173. Fructose is the sweetest natural sugar, and it hits the tongue firstGram for gram, fructose tastes roughly 1.2 to 1.8 times as sweet as table sugar, making it the sweetest carbohydrate found in nature. Its sweetness arrives sooner, peaks higher an…
1174. Working out one sugar molecule helped earn a string of Nobel PrizesGlucose is life's main fuel, made from water and carbon dioxide by plants and burned by every organism. Understanding it proved so central to chemistry and medicine that it earned…
1175. Your muscles hoard sugar they refuse to share with the rest of your bodyAn adult's muscles hold roughly 400 grams of glycogen, several times what the liver stores. Yet muscle cells lack the enzyme needed to release glucose into the blood, so that fuel…
1176. The chemist mocked in 1825 for weighing a molecule too big to believeJohann Friedrich Engelhart noticed that hemoglobin carries iron in a fixed ratio across species, and from iron's atomic mass he worked out a molecular weight in multiples of 16,00…
1177. Roosters, bending seedlings and cut nerves revealed the body's chemical messengersIn 1849 Arnold Berthold moved a rooster's testis into its abdomen and watched the bird keep crowing and strutting as normal. Location did not matter, he reasoned, so something che…
1178. Insulin keeps racking up firsts in the history of protein scienceInsulin was the first peptide hormone ever found, the first protein to have its full amino acid sequence read, the first protein made by chemical synthesis and the first produced …
1179. Dopamine is not the pleasure chemical; it flags what is worth pursuingHeadlines call dopamine the molecule of pleasure. Pharmacologists now describe it differently: it marks how strongly an outcome should attract or repel us, steering behaviour towa…
1180. Your morning coffee may mostly be curing yesterday's coffeeCaffeine works by impersonating adenosine, a molecule that makes the brain feel tired, and blocking its receptors. But in regular drinkers tolerance builds fast, and researchers a…
1181. Sugars coat your cells and can switch proteins on and offCarbohydrates are not just fuel in bread and pasta. Sugar chains decorate the outside of cells, help them recognise one another, guide how proteins fold, and in some cases act as …
1182. Flamingos are pink because of what they eat: carotenoid pigmentsThe orange of carrots, the red of tomatoes and salmon, the yellow of egg yolks and the colour of flamingo feathers all come from one pigment family. More than 1,100 carotenoids ar…
1183. Starch and cellulose are both glucose, joined by a bond that changes everythingPotatoes and paper are made of the same sugar. Starch links its glucose one way and coils into something we digest easily; cellulose links it the other way into straight, stiff ro…
1184. Chemical biologists build molecules to interrogate living cellsBiochemistry asks what chemistry goes on inside living things. Chemical biology flips the question, using synthetic molecules as tools to probe and steer cells, from sugars that t…
1185. Chitin armours insects, colours butterflies, and makes a beetle unusually whiteAbout a billion tonnes of chitin are made in the living world every year, second only to cellulose among natural polysaccharides. It forms crab shells and mushroom cell walls, and…
1186. Leaves look green because chlorophyll rejects the green lightChlorophyll soaks up blue and red light and handles green poorly, so green is what bounces back to our eyes. Its real job is splitting water with captured sunlight, a reaction tha…
1187. Cholesterol is why animal cells can live without wallsPlants and most bacteria wrap their cells in rigid walls. Animal cells instead stiffen their flexible membranes from within, slotting cholesterol between the fatty molecules. The …
1188. Cocaine once transformed surgery as a local anaesthetic, then medicine abandoned itKarl Koller's discovery that cocaine numbs tissue is ranked the second most important advance in the history of anaesthesia. Today it is almost gone from hospitals, displaced by s…
1189. Caroline Herschel was raised for housework and became the first salaried woman scientistTyphus left Caroline Herschel barely 1.30 metres tall and blind in one eye, and her mother planned a life of servitude for her. Instead she followed her brother William to England…
1190. Charles Parsons gatecrashed Queen Victoria's naval review in a turbine-powered speedboatIn June 1897, with admirals and a prince looking on, an uninvited little vessel called Turbinia tore through the fleet at 34 knots, faster than anything the Royal Navy owned. Its …
1191. Babbage's difference engine finally worked in 1991, 120 years after his deathCharles Babbage designed a mechanical calculator and a programmable computer in the 19th century but never saw either completed. In 1991 engineers built his difference engine from…
1192. Before the Beagle, young Darwin was a bored medical student and beetle hunterThe man who explained how species change nearly became a country parson. Charles Darwin found medical lectures dull and surgery distressing, preferred riding and shooting at Cambr…
1193. Expelled over a deformed foot, Charles Hermite went on to prove e transcendentalThe École Polytechnique turned Charles Hermite away after a single year because of a deformity in his right foot. He never graduated from it, yet came back as an examiner and prof…
1194. You recycle roughly your own body weight in ATP every dayAn average adult makes and breaks down about 50 kilograms of ATP daily, yet holds only a tiny amount at any moment. The molecule works like a rechargeable battery, spending one ph…
1195. Why Americans say epinephrine and Europeans say adrenalineThe same hormone carries two names because of a trademark. John Abel extracted it from adrenal glands in 1897 and called it epinephrine; Jōkichi Takamine patented a purified versi…
1196. Morphine, caffeine and nicotine belong to one bitter chemical familyQuinine, caffeine, nicotine, morphine and strychnine all share one feature: at least one nitrogen atom in a natural molecule. Chemists call them alkaloids, a name coined in 1819 b…
1197. The first amino acid was found in asparagus, and named after itNature makes more than 500 amino acids, but life builds its proteins from just 22 of them. Chemists began finding these molecules in 1806, starting with a compound pulled from asp…
1198. Six elements make up more than 99 percent of the mass of your cellsCarbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur account for over 99 percent of cell mass. Biochemistry studies how those few ingredients become living machinery, a field…
1199. Autumn's yellows were in the leaves all summer, hidden by chlorophyllWhen leaves turn in autumn, most of the yellow and orange is not new at all. Those pigments sat there all year, masked by green chlorophyll until it broke down. The reds are diffe…
1200. Four elements make up 96 percent of your body's massOxygen, carbon, hydrogen and nitrogen account for almost all of a human body by weight. From those few ingredients, living things assemble proteins, sugars, fats and genetic mater…

Open the feed