Science
Living things, matter, energy and the Earth, explained step by step. Clear diagrams and everyday examples connect what you learn to the world around you.
Chapter 1 — The Chemical Basis of Life
What living bodies are built from: the elements, the four biological molecules, and a close look at carbohydrates.
Chapter 2 — Motion in a Straight Line
Describing motion along a line: distance and displacement, speed, velocity, acceleration, motion graphs, and falling under gravity.
Chapter 3 — The Structure of Matter
What everything is built from: inside the atom, how electrons are arranged, the periodic table and the patterns in it, and how a chemical formula is written.
Chapter 4 — Newton's Laws of Motion
Why motion changes: force and friction, the three laws of motion, momentum, and the difference between mass and weight.
Chapter 5 — Friction
The force that resists motion: how it adjusts itself, its static, limiting and dynamic states, what it depends on, and where it helps and hinders.
Chapter 6 — The Structure and Function of Plant and Animal Cells
The unit every living body is built from: how cells were found, what a light and an electron microscope each show, the organelles and their jobs, and how cells grow and divide.
Chapter 7 — Quantification of Elements and Compounds
How chemists count what is too small to count: relative atomic and molecular mass, the Avogadro constant, the mole, and turning a mass in grams into a number of particles.
Chapter 8 — Characteristics of Living Organisms
What every living thing does and no stone does: cellular organization, nutrition, respiration, irritability, excretion, movement, reproduction and growth — and the cases, viruses above all, where the line will not stay drawn.
Chapter 9 — Resultant Force
The single force that can replace several: forces in a line pulling together and pulling against each other, parallel forces on different lines of action, and what happens when two forces are inclined to one another.
Chapter 10 — Chemical Bonds
Why a hundred elements make millions of compounds: the valence shell an atom is trying to fill, the electron transfer that gives an ionic bond and the sharing that gives a covalent one, and the properties — melting point, conductivity, what dissolves in what — that follow from which of the two holds a substance together.
Chapter 11 — Turning Effect of a Force
The turning half of what a force can do: the axis a body turns about, why the moment of a force depends on the perpendicular distance as much as on the force itself, when opposing moments balance, and the pair of equal opposite forces — a couple — that turns a body without pushing it anywhere.
Chapter 12 — Equilibrium of Forces
What it takes for a body under several forces to stay exactly where it is: the tension that holds a hanging object up, the reaction a table pushes back with, and the conditions two forces, three parallel forces and three forces meeting at a point must each satisfy before nothing moves at all.
Chapter 13 — The Living World
How every living thing on Earth is sorted and named: why classification is worth doing at all, the three domains and the kingdoms inside them, the plants split by flower and seed, the animals split by backbone, and the two-word Latin name that means the same thing to a reader in any language.
Chapter 14 — Continuity of Life
How one generation of living things gives rise to the next: the two ways anything reproduces at all, a plant propagated from a cutting or a grafted bud or a flask of tissue, the flower and the pollen that reaches it, the fruit and seed that follow and how far they travel, and in ourselves adolescence, the two reproductive systems, the monthly cycle, and the nine months from one fertilised cell to a child.
Chapter 15 — Fluid Pressure and Its Applications
What happens when a force is spread over an area: the pressure a column of liquid makes at any depth and why its shape does not matter, how a liquid carries that pressure undiminished to a jack, a hoist and a car's brakes, the weight of the atmosphere measured in a tube of mercury and put to work in a straw and a siphon, and the upward push that decides whether a thing floats or sinks.
Chapter 16 — Changes of Matter
What separates melting ice from rusting iron: the changes that rearrange a substance and the changes that make a new one, the four patterns every reaction falls into, how to write a reaction in symbols and balance it, how differently metals treat air, water, acids and each other's salts, the activity series that ranks them and the blast furnace that uses it, and the preparation, properties and uses of hydrogen, oxygen and carbon dioxide.
Chapter 17 — Rate of Reaction
Why a firecracker is over in an instant and a nail takes years to rust: what the rate of a reaction is, the two things you can measure to find it, and the four factors that change it — how finely the reactants are divided, how hot they are, how concentrated they are (or, for gases, how hard they are squeezed), and whether a catalyst is present. It ends with the graph that shows all of it at once.
Chapter 18 — Work, Energy and Power
What it means to do work on something, the two kinds of mechanical energy a body can hold, and how quickly that work gets done. Work is a force multiplied by the displacement it produces; energy is the capacity to do it, stored either by motion or by position; power is the rate. It ends where all three meet — a bicycle freewheeling over a hill, trading one kind of energy for the other and back again.
Chapter 19 — Current Electricity
What is actually moving when a current flows, and what decides how much of it moves. It starts with a rubbed comb picking up paper, turns those resting charges into a flow, and then builds the three quantities a circuit is described by — current, potential difference and resistance — ending at Ohm's law, the resistor colour code, and why a bird on a high-voltage wire is unharmed.
Chapter 20 — Heredity
Why a child resembles its parents, and why it is not identical to them. It starts with traits you can check on your own hands and face, follows Mendel into a monastery garden where seven pairs of pea characters gave the same 3 : 1 answer every time, and builds from his invisible "factors" to the gene, the chromosome and the DNA base sequence — ending at sex determination, four inherited disorders, and what a laboratory can now do with a gene it has read.