Tag
Stuff & materials
Metal, glass, plastic, wood, and what everything is made from — 102 tiny stories across 8 shelves.
What things are made of
Atoms, metal, glass, plastic, and every kind of stuff — 59 stories.
All what things are made of →Sour, and eager to give something away
What Makes Something an Acid?
An alkali soaks those particles up instead, so the two cancel to salty water and heat — and your stomach survives its own acid on renewed slime.
Let’s go →99.8 per cent nothing
The Solid That Is Almost Entirely Air
Aerogel is a gel with the liquid removed and the solid skeleton left standing — a feat of drying rather than chemistry, and the best insulator we can make.
Let’s go →Wrong-sized atoms get in the way
Why Is Pure Gold Too Soft for a Ring?
A pure metal bends because its atoms slide in neat rows. Mix in a differently sized atom and the rows jam, which is why alloys beat what went into them.
Let’s go →Light, cheap to reuse, and it protects itself
Why Are Drink Cans Made of Aluminium?
Aluminium is light, does not rust because it seals itself, and can be recycled with a fraction of the energy it took to make.
Let’s go →The part that would not burn
What Is Left When Something Burns?
Barely one part in a hundred of a burnt log stays behind, and that pale grey pile is the soil minerals a tree spent its whole life collecting.
Let’s go →Pieces too small to see
What Is Everything Made Of?
Everything around you is built from about a hundred kinds of atom, so small that a sheet of paper is half a million of them thick.
Let’s go →Fire welds the grains together
Why Does Baking Mud Make Stone?
Firing clay drives out the water locked inside and heats the grains until their edges fuse. Soft mud comes out behaving, for all purposes, like stone.
Let’s go →Shaking a mixture until it gives up
How Does Cream Turn Into Butter?
Cream is fat droplets floating in water, each in a protective coat. Churning smashes those coats off so the fat clumps and the watery part drains away.
Let’s go →A skin of glass
Why Doesn't a Glazed Pot Leak?
A fired pot is porous and leaks; glaze is powdered glass melted over it, and it has to melt low enough and shrink by exactly the right amount.
Let’s go →A cliff of tiny shells
What Is Chalk Made Of?
Drop a stick in vinegar and it fizzes, the same reaction acid rain runs on limestone — though most sticks sold today never came near an ancient sea.
Let’s go →Burning wood twice
Why Does Charcoal Burn Hotter Than Wood?
Charcoal is wood already half burned: baked without air until only carbon remains, so everything that would have made smoke has gone.
Let’s go →Splitting a liquid into two
How Does Milk Become Cheese?
Cheese-making starts by splitting milk into solid curds and watery whey, throwing most of the whey away, then pressing, salting and ageing what is left.
Let’s go →Flat plates with water between them
Why Can You Shape Clay but Not Sand?
Clay holds a shape because its grains are flat plates sliding on a film of water, which then pulls them together wherever you leave them.
Let’s go →Rot it, roast it, grind it
How Does a Bitter Bean Become Chocolate?
A raw cocoa bean tastes horrible. Chocolate exists because somebody let the beans ferment first, then dried, roasted and ground them.
Let’s go →It sets by reacting, not by drying
Why Does Concrete Go Hard Under Water?
Concrete does not dry out. The cement reacts with water and grows interlocking crystals, which is why it sets at the bottom of a river.
Let’s go →Loose electrons, and a price that works
Why Are Wires Made of Copper?
Silver conducts slightly better, yet almost every wire is copper: its outer electrons drift free, and it wins on price and on bending.
Let’s go →Mostly air, in tiny boxes
Why Does Cork Float?
Cork is bark more than half made of sealed air pockets, which is why it floats, squashes narrower rather than wider, and blocks heat and sound.
Let’s go →A fluffy seed parachute
How Does a Plant Become a T-Shirt?
Cotton is neither leaf nor stem. It is the fluff a plant grows so its seeds catch the wind, combed straight and twisted until the fibres grip each other.
Let’s go →Sunlight from a very long time ago
What Is Crude Oil?
Crude oil is the squashed remains of tiny sea creatures, cooked under rock — so burning it releases sunlight caught a hundred million years ago.
Let’s go →Making a colour hold on
How Does Colour Stay in Cloth?
Getting colour onto cloth is easy; surviving twenty washes is the hard part, so a dye bonds to the fibres rather than sitting on the surface.
Let’s go →One kind of atom, all the way through
Why Is There a Table of Everything?
An element is a substance made of a single kind of atom, and the whole world around you is built from about ninety of the 118 known.
Let’s go →Twist turns short fibres into long ones
How Does Fluff Become Thread?
Twisting short fibres squeezes them hard against one another, and the friction between them is enough to make the whole bundle behave as one long strand.
Let’s go →Letting something rot on purpose
What Is Fermenting?
Fermenting means letting chosen microbes eat sugar, which changes the food and makes it hostile to anything that would spoil it.
Let’s go →Mostly air, held in a shape
Why Is Foam So Light?
Packaging foam is 95 to 98 per cent air. Trapped air cannot circulate, so it insulates — and thousands of bubble walls buckling is what absorbs a knock.
Let’s go →Oil goes far hotter than water
Why Does Frying Taste Different From Boiling?
Water stops dead at 100 degrees, so boiling can only soften. Oil sails on to 180, and that is where browning, crisping and most of the flavour happen.
Let’s go →Flow into every crevice, then stop flowing
How Does Glue Hold Two Things Together?
Two flat-looking surfaces touch at only a few high points, so glue has to be runny enough to flood every tiny pit, and then stop being runny.
Let’s go →The metal that will not change
Why Is Gold So Special?
Almost every metal dulls or rusts. Gold sits unchanged for thousands of years, bends easily, is genuinely rare, and was made in dying stars.
Let’s go →Three thousand years, unspoiled
Honey Found in a Tomb Is Still Honey
Honey does not spoil, because three defences work at once — almost no free water, unexpected acidity, and an enzyme the bees add that makes peroxide.
Let’s go →A candle, a mouse, and a jar
How We Found Out What Air Is
Sealing a candle and a mouse under a jar showed that air is a mixture, and that only one part of it keeps a flame or an animal alive.
Let’s go →Some colour dissolves, some just sits there
Why Does Ink Stay on the Paper?
Sunlight pulls dye molecules apart far faster than it harms a solid pigment speck, which is why the archive keeps pigment and the receipt fades.
Let’s go →A lined pit that runs out of air
Where Does Rubbish Actually Go?
Digs into old tips turn up decades-old newspapers still readable and food scraps barely changed. A landfill is a store rather than a solution.
Let’s go →Stopping something from rotting
How Does Skin Become Leather?
Untreated skin stiffens and then rots. Tanning clamps its fibres together chemically so bacteria cannot eat them, and the result lasts for decades.
Let’s go →Melted, then cooled too fast to crystallise
How Do You Turn Sand Into a Window?
Glass is melted sand cooled so fast that its atoms freeze in a jumble, never getting the chance to line up into the crystals they would prefer.
Let’s go →Fibres, shaken flat and let dry
How Is Paper Made From a Tree?
Nobody makes the fibres — the tree did. A mill only ungums them in water, drains the pulp flat on a mesh, and presses until they grip again.
Let’s go →How hard the atoms hold on
Why Do You Need a Furnace to Melt Iron?
The tipping point is sharp: a degree below it the lump holds its shape. Tungsten atoms grip hardest of all, which is why old bulbs used tungsten wire.
Let’s go →Mixed together, not joined together
Why Can You Get the Salt Back Out?
Stir iron filings into sand and a magnet lifts them straight back out. Air, milk, soil and steel are all mixtures; genuinely pure things are rare.
Let’s go →Two things make a third thing
What Happens When Atoms Join Up?
An explosive gas and the gas fires need combine to make water, which puts fires out. Atoms joined up behave nothing like the atoms that went in.
Let’s go →A thread made from nothing that grew
Why Was Nylon Invented?
Nylon was the first useful fibre that came from neither plant nor animal: long molecule chains pulled straight, endless and rot-proof.
Let’s go →Three jobs in one tin
What Is Paint Made Of?
Every paint is the same three things: coloured powder, a glue to hold it on the wall, and a liquid that thins it and then leaves once it dries.
Let’s go →Millions of small links, joined into chains
What Is Plastic Actually Made Of?
Heating lets the chains slide without breaking, so plastic can be moulded again — but different chains refuse to mix, which is why sorting matters.
Let’s go →Melting versus mashing
Why Does Glass Recycle Better Than Paper?
Melting rebuilds glass and metal exactly, but tearing paper apart shortens its fibres a little each time, so paper eventually runs out of lives.
Let’s go →Twist, and twist again
Why Is a Rope Stronger Than Its Threads?
Pulling on a rope does not stretch its fibres apart, it squeezes them together — so friction stops any short fibre from ever sliding out.
Let’s go →Tangled springs
Why Does Rubber Bounce Back?
Stretching a rubber band pulls no molecules apart. It straightens tangled ones, and they scramble back into knots the moment you let go.
Let’s go →A rock you are allowed to eat
Where Does Salt Come From?
Salt is the one rock people put on their food — left behind wherever seawater dries out, in pans today or in beds buried by seas long gone.
Let’s go →A caterpillar's sleeping bag
Where Does Silk Come From?
Silk is one thread a caterpillar spat out to wrap itself in — sometimes a kilometre of it unwound in a single piece, then woven into cloth.
Let’s go →The bits that did not get to burn
Why Does a Fire Make Smoke?
Smoke is fuel that never finished burning: tiny solid specks that failed to meet enough oxygen, carried off by the hot air rising above the fire.
Let’s go →Fat, turned inside out
How Is Soap Made?
Soap is made by cooking fat with something strongly alkaline until every molecule has a grease-gripping tail and a water-gripping head.
Let’s go →A pinch of carbon changes everything
What Makes Steel Stronger Than Iron?
Add about one percent carbon to iron and it becomes several times stronger, because the carbon jams the layers that used to slide past.
Let’s go →A shape that fits a lock
Why Is Sugar Sweet?
Sugar tastes sweet only because its shape happens to fit a receptor on your tongue — and it is the fuel nearly every living thing runs on.
Let’s go →One plant, four drinks
Why Is Tea Different Colours?
Green, black, white and oolong all come off the same bush, separated only by how long the leaf was left to brown before it was dried.
Let’s go →Scrubbing, and rebuilding
What Is Toothpaste Actually Doing?
Most of the cleaning is the brush. The paste is mild grit, detergent and flavour, plus the fluoride that actually rebuilds the enamel.
Let’s go →The wick drinks its own fuel
Why Does a Candle Burn for Hours?
The wick is not the fuel and solid wax will not catch: the flame melts the wax, the wick lifts it, and what actually burns is the vapour.
Let’s go →Glowing gas, not glowing wood
What Actually Is a Flame?
A flame is not the wood burning. It is gas driven out of the wood by heat, glowing as it meets oxygen — which is why heat, air or fuel each put it out.
Let’s go →The same atom, two arrangements
Why Is Diamond Hard and Pencil Lead Soft?
The grey line a pencil leaves is stacks of carbon sheets sheared off onto the paper — the very same atoms that let diamond scratch everything.
Let’s go →Light finds nothing to grab
Why Can You See Through Glass?
Glass electrons can only absorb one exact size of bite and visible light is too small, so a window stops sunburn but never the view.
Let’s go →A shared pool of electrons
Why Is Metal Shiny?
Polishing adds no shine at all — rough silver bounces back just as much light, only in every direction. Gold looks warm because it eats a little blue.
Let’s go →Nothing alive has the tool for it
Why Does Plastic Never Rot?
Life evolved keys for wood, leaf, bone and fat over a very long time. A bacterium that can slowly eat PET turned up beside a Japanese plant in 2016.
Let’s go →A bundle of drinking straws
Why Does Wood Split One Way?
One pale band of spring growth plus one dark band of late summer is a single year of the tree. Plywood works by leaving no easy direction to split.
Let’s go →It is mostly trapped air
Why Is Wool So Warm?
Wool traps a great deal of still air in its crimped fibres, and still air carries heat badly — though its one-way scales shrink in a hot wash.
Let’s go →Life & body
Seeds, hearts, senses, and growing things — 12 stories.
All life & body →They only kill one kind of thing
Why Don't Antibiotics Work on a Cold?
Antibiotics attack structures only bacteria have, so they do nothing to viruses — and every unnecessary course breeds resistance.
Let’s go →Pre-built, then inflated
How Does Bamboo Grow So Fast?
Bamboo grows a metre a day because the whole stem is built underground in advance, then simply pumped full of water and stretched out.
Let’s go →Dead armour over a living pipe
What Is Bark For?
The rough outside is dead armour. The thin living layer just beneath carries the tree's food downwards, which is why cutting a ring round a trunk kills it.
Let’s go →A heap that cooks itself
Why Does a Compost Heap Get Hot?
A heap has to reach about a cubic metre before its middle can hold heat, and once it does the warmth kills weed seeds and many plant diseases.
Let’s go →Leaves cheap enough to keep
Why Don't Pine Trees Lose Their Leaves?
A waxy narrow needle survives a winter of frozen ground where a broad leaf cannot, so the pine is already working when the light returns.
Let’s go →A backstop for your fingertip
What Are Fingernails For?
Fingernails are a hard backstop that lets your soft fingertip press against something, making fine touch and picking things up possible.
Let’s go →Dead rope, pushed out of a living hole
Why Does Cutting Hair Not Hurt?
A round follicle pushes out a straight strand and an oval one a curly strand, and grey arrives when the pigment cells at the root simply stop.
Let’s go →It does not, and that is the problem
How Does a Pill Know Where to Go?
A swallowed pill goes everywhere in your body and works only where its shape fits something, which is also exactly why side effects happen.
Let’s go →It is holding your neck, not your head
Why Does a Pillow Help You Sleep?
Lying down leaves a gap between your head and the mattress. A pillow fills it, so no neck muscle has to hold your head up for seven hours.
Let’s go →Too much, in the wrong place
What Makes Something Pollution?
Nothing is pollution by itself. It becomes pollution when more of it arrives somewhere than that place can break down or carry away.
Let’s go →A net, cast in seconds
How Does a Cut Stop Bleeding?
The scab is only a lid. Underneath it new skin creeps in from both edges, and when it meets in the middle the crust has nothing left to hold on to.
Let’s go →Borrowing someone else's trunk
Why Do Vines Climb?
Building a trunk is enormously expensive, so a vine grows thin and fast, grabs a support somebody else built, and spends the rest on leaves.
Let’s go →Everyday wonders
Kitchen, bubbles, echoes, and odd little magic — 10 stories.
All everyday wonders →The laziest possible shape
Why Are Bubbles Always Round?
The soap film pulls itself as small as it can, and the smallest surface that will hold a given volume of air is a sphere. Roundness is not a choice.
Let’s go →Kind to the blade, unkind to germs
Why Are Chopping Boards Made of Wood?
Wood is soft enough to spare a knife edge and wicks moisture away from bacteria. Keeping separate boards, though, matters far more than the material does.
Let’s go →Atoms joining a queue
How Do Crystals Grow?
Atoms can only attach in certain positions, so a repeating pattern inside shows up as flat faces outside. Salt makes cubes because it stacks in cubes.
Let’s go →Smell molecules escaping
Why Does a Fridge Smell of Everything at Once?
Every food quietly gives off molecules, and a sealed cold box gives them nowhere to go. Fatty foods then soak them up and hold on to them.
Let’s go →It steals heat faster
Why Does Metal Feel Colder Than Wood?
Metal and wood in the same room are the same temperature. Metal only feels colder because it pulls heat out of your hand very much faster.
Let’s go →Tangled chains straightening out
Why Do Rubber Bands Snap Back?
Rubber is a mass of tangled molecule chains. Stretching straightens them, and they snap back for the simple reason that tangled is far more likely.
Let’s go →Iron combining with oxygen
Why Does Metal Go Rusty?
Rust is iron chemically joining with oxygen and water to become something new and crumbly, and it flakes off to expose fresh metal underneath.
Let’s go →All the force in one line
Why Is a Sharp Knife Safer Than a Blunt One?
A sharp edge is a few hundred atoms across, so almost any push cuts. A blunt one makes you lean on it, and a skid sends that stored force somewhere else.
Let’s go →A molecule with two ends
How Does Soap Clean?
One end of a soap molecule grips grease and the other grips water, so grease is wrapped in a water-friendly ball and simply rinses off instead of clinging.
Let’s go →Metal and protein shaking hands
Why Does Food Stick to the Pan?
Food sticks because its proteins genuinely bond to hot metal. It lets go on its own once a dry crust has formed, or never bonds if oil keeps the two apart.
Let’s go →Animals
Creatures on land, in the sea, and in the air — 8 stories.
All animals →Making the pond it needs
Why Does a Beaver Build a Dam?
A beaver cannot defend itself on land, so it floods the land instead. The dam makes a pond deep enough to put its front door safely under the surface.
Let’s go →One animal in every four
Why Are There So Many Kinds of Beetle?
Of every four kinds of animal that have ever been named, roughly one is a beetle — largely thanks to a pair of armoured wing cases.
Let’s go →Holding onto still air
Why Do Animals Have Fur?
Fur works by trapping a layer of still air against the skin, and animals fluff it, shed it and grow it back as the seasons change.
Let’s go →Growing out of your own container
Why Do Animals Shed Their Skin?
A snake crawls out of its skin in one piece because it cannot grow inside it — and the hours before the new one hardens are its most dangerous.
Let’s go →And it stops one of them to swim
An Octopus Has Three Hearts and Blue Blood
An octopus runs on copper-based haemocyanin rather than iron-based haemoglobin: blue, good in cold water, and inefficient enough to need three hearts.
Let’s go →Wool that never stops
Why Do Sheep Need a Haircut?
A wild sheep sheds its coat every year. Thousands of years of breeding took that shedding out of farm sheep, so somebody now has to do it for them.
Let’s go →One foot, one shell, no hurry
How Does a Snail Carry Its House?
Snail slime grips when it is pressed slowly and turns slippery when pushed hard, which is how a snail climbs glass without ever sliding back down.
Let’s go →A shell that is part of the animal
Can a Tortoise Come Out of Its Shell?
Because the ribs grew outwards, a tortoise carries its shoulder blades inside its own ribcage — true of no other backboned animal on the planet.
Let’s go →How things work
Everyday machines, taken apart — 7 stories.
All how things work →Rope gripping rope
Why Does a Knot Hold?
Nothing in a knot is glued or clipped. Pulling the rope squeezes its own crossings together, and rope pressed on rope refuses to slide.
Let’s go →Steel on steel, barely gripping
How Can One Engine Pull a Two-Kilometre Train?
Steel wheels on steel rails barely rub, so one engine can pull an enormous train — and barely grip, so it cannot stop quickly.
Let’s go →Lifting half the threads
How Does a Loom Turn Thread Into Cloth?
Weaving is not sewing: long threads are held tight, half of them lifted to open a gap, and a crossing thread is shot straight through it.
Let’s go →Sheets that slide off
Why Does a Pencil Leave a Mark?
The name comes from a 16th-century find people mistook for lead. More clay in the mix means fewer sheets come away, which is what makes a line fainter.
Let’s go →Two threads that catch each other
How Does a Sewing Machine Stitch?
The needle never carries thread all the way through. It pushes a loop under the cloth, and a second hidden thread is hooked inside that loop.
Let’s go →Grip, not speed
Why Do Tractors Have Huge Back Wheels?
A tractor is built to pull, not to travel: huge rear wheels give the grip that pulling needs and spread the weight so it does not sink.
Let’s go →Spreading the load
Why Do Trucks Have So Many Wheels?
Road damage depends on what each wheel presses down, not on the total, so a truck spreads thirty cars' worth of weight across many axles.
Let’s go →Physics
Invisible forces you can play with — 4 stories.
All physics →Cavendish, 1798
How Anyone Weighed the Earth
Henry Cavendish weighed the Earth by measuring the faint pull between four lead balls, in a sealed shed he watched through a telescope from outside.
Let’s go →You could not start, either
What If Friction Stopped for One Minute?
Everyone expects to slide. Almost nobody expects to be unable to start, hold, stand, or keep a single screw or knot from letting go.
Let’s go →Not the chair, not this page
You Have Never Touched Anything
Solid contact is a force, not a meeting — the outer electrons of two surfaces repel each other hard enough that nothing ever quite arrives.
Let’s go →Fifteen times faster through steel
Sound Goes Faster Through a Wall Than Through Air
Sound travels by particles shoving their neighbours, so the stiffer the material the faster the shove passes — steel beats water, and water beats air.
Let’s go →Space
Crashy night-sky stories — 1 story.
All space →Earth & sky
Weather, light, and the air around us — 1 story.
All earth & sky →