What Everything Is Made Of
Atoms, reactions and the elements Everything Is Made of Atoms · Solid, Liquid, Gas · Chemical Reactions · Mixing and Separating · Acids and Bases · The Elements · Hydrogen · Helium · Carbon · Oxygen · Nitrogen · Iron · Gold · Copper · Aluminium · Sodium.
Ages 11–13
What's inside
Everything Is Made of Atoms — the tiniest building blocks
Here is one of the biggest ideas in all of science: everything — this page, the air, your hand, a distant star — is made of the same kind of tiny building blocks, called atoms. Atoms are so small it's almost impossible to picture: you'd have to line up millions just to cross the width of a single hair. Yet these unimaginably tiny pieces, arranged in different ways, make up absolutely everything there is.
Solid, Liquid, Gas — the three faces of matter
Ice, water and steam seem like three totally different things — one is hard, one is wet, one vanishes into the air. But here's the surprise: they are all exactly the same substance, the very same water molecules, just behaving in three different ways. These three ways — solid, liquid and gas — are called the states of matter, and almost everything can switch between them. The secret to which state you get is simply heat.
Chemical Reactions — when new stuff is made
So far we've mixed and melted things, but the atoms stayed the same. Now for chemistry's real magic trick: reactions, where atoms actually break their bonds, swap partners, and join up in new ways to make a brand-new substance with brand-new properties. This is how you turn one thing into a completely different thing — and it's happening all around you, all the time.
Mixing and Separating — when stuff combines without changing
Not everything that's combined has reacted. Often two substances are simply mixed together — jumbled up, but each one still quietly being itself, unchanged. Sand stirred into water, salt dissolved in the sea, the different gases in the air you breathe: these are all mixtures. And because nothing has actually reacted, the clever payoff is that you can usually pull a mixture apart again — a skill that turns out to be one of the most useful in all of science.
Acids and Bases — the sour and the soapy
Some substances have a hidden personality that chemists sort into two great opposite families: acids and bases. You already know them without realising it — the sharp sourness of a lemon or vinegar is an acid, while the slippery, soapy feel of soap or baking soda is a base. They're chemical opposites, and the fun begins when you learn to spot them, measure them, and watch what happens when they collide.
The Elements — the universe's ingredient list
If atoms are the letters, then the elements are the alphabet — the full set of basic ingredients from which everything in the universe is built. An element is a substance made of only one kind of atom: gold is only gold atoms, oxygen only oxygen atoms. Astonishingly, there are only about 90 of these natural building blocks, and long ago a Russian scientist arranged them all into one brilliant chart that reveals their hidden patterns: the periodic table.
Hydrogen — the lightest element
Hydrogen is where chemistry begins. It sits at the very top of the periodic table because it is the smallest, simplest atom possible: one proton in the middle and one electron whizzing around it. Almost everything else is built up from bigger, more crowded atoms — but hydrogen keeps it to the bare minimum.
Helium — the balloon gas
Helium is a noble gas, which is chemistry’s way of saying it is a loner: its outer ring of electrons is already full, so it feels no need to bond with anything. That makes it one of the calmest, safest elements there is — it will not burn and will not react, no matter what you do to it.
Carbon — the element of life
Carbon is the great connector of chemistry. A single carbon atom can grab onto four other atoms at once, which lets it build long chains, rings and branching webs like no other element can. That talent for building is exactly why life chose carbon as its main material.
Oxygen — the breath of life
Oxygen is the element that ties breathing, burning and rusting together. It is a colourless, tasteless gas that makes up about a fifth of the air, and it is fantastically eager to react — always grabbing electrons from other atoms. That grabbing is what powers your body and lights a fire.
Nitrogen — most of the air
Nitrogen is the quiet giant of the air. It makes up nearly four fifths of every breath, yet you barely notice it because it is so unreactive — its two atoms clamp together with one of the strongest bonds in all of chemistry and simply refuse to join anything else.
Iron — the metal that built the world
Iron is the workhorse metal of human history. It is strong, common and cheap, so once people learned to smelt it from rock they used it for tools, weapons, ploughs and eventually the steel skeletons of whole cities. A single element quietly holds up most of the built world.
Gold — the metal that never rusts
Gold has fascinated people for as long as history records, and the reason is chemistry: it barely reacts with anything, so it never rusts, tarnishes or fades. A gold coin buried for two thousand years comes out as bright as the day it was made.
Copper — the wire in every wall
Copper is the metal that quietly wires the modern world. It is soft, easy to bend, and one of the best everyday conductors of electricity there is, which is why it hides inside the walls, cables and gadgets all around you. It was also one of the very first metals people ever used, thousands of years ago.
Aluminium — light, strong and everywhere
Aluminium is a light, silvery metal that is genuinely everywhere: in cans, foil, window frames, bicycles and the bodies of planes. What makes it special is a rare mix of being both very light and reasonably strong, and it protects itself with an invisible skin so it never rusts.
Sodium — the metal in your salt
Sodium is a perfect example of how chemistry can completely change a substance. On its own it is a soft, silvery metal so reactive it must be kept under oil, because even the moisture in the air sets it off. Yet this dangerous metal is one half of the most ordinary thing in your kitchen: salt.
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