Archive

Mathematics & Logic

How reinforcement learning works: a program gets a score instead of correct answers, and the score can teach the wrong lesson.

Mathematics & Logic

How machines learn from data nobody has labelled, by sorting it into groups, compressing it, and predicting the parts that were hidden from them.

Mathematics & Logic

Claude Shannon measured information by how surprising a message is. The same measure explains file compression and how language models are trained.

Mathematics & Logic

Bayes’ rule says how far new evidence should move a belief, and why a positive test for a rare disease often means less than it seems.

Mathematics & Logic

Vectors and matrices: how a photo, a word or a film becomes a list of numbers, and how search, recommendations and neural networks compare them.

Psychology

Many celebrated psychology results shrank or vanished when other scientists repeated the studies. Why that happened, and what the field changed.

Psychology

In 1971 Philip Zimbardo ran a mock prison in a Stanford basement and stopped it after six days. What he concluded, and what the archives showed in 2018.

Psychology

Why a quick answer can feel certain and still be wrong, what careful thinking costs, and when a gut feeling can be trusted.

Society

What inflation is, how it is measured, what pushes prices up, and why central banks aim for 2 per cent a year instead of zero.

Chemistry

A soap molecule holds water at one end and grease at the other. That is how it lifts oil off a plate, and how it breaks some viruses apart.

Physics

From sundials and water clocks to quartz and caesium: how each clock counts something that repeats, and why the second is now defined by an atom.

Biology

How birds, sea turtles, salmon and desert ants find one particular place, using the sun, the stars, the Earth’s magnetic field and smell.

Psychology

Why a habit is set off by a place or a cue and not by an intention, how long one takes to form, and what helps to change one.

Mathematics & Logic

How ciphers work, how counting letters broke them for centuries, and why modern encryption depends on a key and on maths that is hard to reverse.

Mathematics & Logic

The design behind chat assistants: how text becomes numbers, how each word is weighed against every other, and why a fluent reply can still be false.

Mathematics & Logic

How a neural network learns to recognise pictures from examples instead of written rules, why that took decades to work, and where it still fails.

Mathematics & Logic

Rich Sutton’s 2019 argument that AI methods which use more computing keep beating methods built on human expertise, and what his critics reply.

Society

Marshall McLuhan’s claim that the way a message reaches us shapes us more than the message does, and the main objections to it.

Physics

The eleventh-century scholar who showed that we see by light entering the eye, and who made experiment the test of a theory in optics.

Psychology

Recalling an answer from memory strengthens it more than reading it again, so a quiz can teach as well as check.

Psychology

The same hours of study last far longer spread out than done in one go. Why the gaps help, and how a review schedule sets them.

Society

How news is chosen and worded, how persuasion and propaganda work on us, how numbers mislead, and why checking before you share matters.

Society

How we know what happened before anyone alive was born, from sources and how they are tested to Ibn Khaldūn’s rule for catching the impossible.

Society

Why nearly all Egyptians live on a twentieth of Egypt, what sets a population growing, and why every map of the world is a little wrong.

Society

Why cities appeared, what holds them together, and Ibn Khaldūn’s account of why the families that rule them rise and fall.

Society

Why a slip of printed paper buys a week’s food, how one number tells millions of strangers what to do, and what the market inspector was for.

Society

What a culture is, how it is passed on and borrowed, and how language, spoken and written, carries it.

Society

The unwritten rules, the positions and the ties that turn a crowd of strangers into a society, and how a newborn becomes one of its members.

Psychology

Why a pounding heart can mean dread or delight, what a threat that never ends does to the body, and how a prize can spoil a pleasure.

Psychology

Why half of us miss a gorilla in plain view, what sets the clock that makes you sleepy, and what a night of sleep does in ninety-minute rounds.

Psychology

Why a name can sit on the tip of your tongue, why a vivid memory can be wrong, and what makes learning stick.

Chemistry

How one element makes diamond and pencil lead, fuels, alcohols and plastics, and the molecules of every living thing.

Chemistry

Why gold is found as nuggets and aluminium never is, why a little carbon turns soft iron into steel, and why a block of zinc keeps a ship from rusting.

Chemistry

Why no filter paper can take the salt out of sea water, and the handful of methods, from a salt pan to a still, that can.

Chemistry

What makes something an acid or a base, how the pH scale ranks them, and what happens when the two meet.

Chemistry

Where the heat of a fire comes from, why a match has to be struck, and why water saves a campfire but turns a pan of burning oil into a fireball.

Chemistry

What a chemical reaction does to atoms, where a burnt log’s mass goes, what decides how fast a reaction runs, and how a catalyst speeds one up without being used up.

Chemistry

Why atoms bond, the three ways they do it (giving, sharing and pooling electrons), and why salt shatters, copper bends and sugar melts on a stove.

Chemistry

What an atom is made of, why the number of protons decides the element, where the elements were made, and how radioactive decay can date a bone.

Biology

Food chains and webs, the flow of energy, the cycles of carbon and water, and what follows when one species goes missing.

Biology

Why food has to be taken apart before you can use it, why the stomach does not digest itself, and where in a cell the energy of a meal is finally released.

Biology

How the heart, blood and lungs carry oxygen to every cell, and how Ibn al-Nafīs worked out the route blood takes through the lungs.

Biology

Where a tree’s wood comes from, how water climbs a hundred metres with no pump, and why a cherry is sweet.

Biology

The few microbes that make us ill, the many that keep us alive, and why an antibiotic that cures a throat infection can do nothing for a cold.

Biology

Why the moths of a smoky city turned dark, why antibiotics stop working, and how farmers made wheat out of a wild grass.

Biology

How Mendel found the rules of inheritance in pea plants, why a trait can skip a generation, and how it is settled whether a child is a boy or a girl.

Biology

How four chemical letters hold the instructions for a body, how DNA copies itself, and how a gene becomes a protein.

Biology

What a cell is, what is inside it, why cells stay small, and how one cell becomes two.

Physics

Charge, current, voltage and resistance, from static on a doorknob to the circuits in a house, and why a bird can sit safely on a power line.

Physics

Your eyes send nothing out. Light comes in, and an idea first tested in a dark room in Cairo still explains the mirror, the rainbow and the red of a sunset.

Physics

Why metal feels colder than wood in the same room, why a hot drink always cools, and why no engine can turn all of its fuel into motion.

Physics

Why astronauts float although gravity is nearly as strong up there, why the Moon never falls down, and how a man in a shed weighed the Earth in 1798.

Physics

Work, joules and watts, why energy changes form but is never used up, and where a car’s energy goes when it brakes.

Physics

What a net force does to an object, why forces always come in pairs, how a rocket speeds up in empty space, and how a lever trades distance for force.

Physics

Speed, velocity and acceleration, how Galileo timed a fall, what an astronaut’s hammer and feather did on the Moon, and why steady motion cannot be felt.