Pearson Edexcel International GCSE in Physics · 4PH1

Physics

Physics is not a list of equations to memorise. Every equation here is introduced only after you understand the relationship it describes — what each quantity really is, why they connect that way, and what happens when one of them changes.

How the qualification is assessed

Two untiered papers. Paper 1 is 110 marks in 2 hours and covers the core content; Paper 2 is 70 marks in 1 hour 15 minutes and covers everything, including the bold P statements. Experimental skills are tested in written questions.

Incandio is aligned to this specification. It is not published by, endorsed by or affiliated with Pearson, and it reproduces none of Pearson's wording — the statement numbers are given so you can check every lesson against your own copy.

65 lessons across 8 topics

They cover 195 of the 195 statements on the specification.

Topic 1 · Forces and motion

How things move and what changes their motion: speed and acceleration, the two motion graphs, Newton's laws, weight, stopping distances, springs, momentum and moments.

• Speed, and What a Distance–Time Graph Is Telling You — Speed as a rate, the units physics insists on, and how to read a journey straight off a graph.
• Acceleration and the Velocity–Time Graph — What acceleration actually measures, why its unit looks strange, and how one graph gives you both acceleration and distance.
• Forces, Vectors and Scalars — What a force actually does, why some quantities need a direction to mean anything, and why that makes a force one of them.
• Resultant Force, Friction and F = ma — Why a moving object stops, what really happens when you add forces up, and the one equation that connects force to motion.
• Weight and Terminal Velocity — What weight actually is, why it is not the same as mass, and what happens to a falling object once the air starts pushing back.
• Stopping Distance — Why a car does not stop when you decide to stop it — and which of the two distances each factor actually lengthens.
• Hooke's Law and Elasticity — Why a spring stretches in proportion to the force — until, quite suddenly, it does not.
• Momentum — Why a slow lorry is harder to stop than a fast bicycle — and why every safety device ever designed does the same one thing.
• Conservation of Momentum — The bookkeeping rule that survives every collision — and why a force is really a rate of change of momentum.
• Moments and Centre of Gravity — Why a spanner works better when it is longer, where an object's weight can be said to act, and how two supports share a load.

Topic 2 · Electricity

Current as flowing charge, voltage as energy per charge, resistance as opposition — plus mains safety, series and parallel circuits, component characteristics and static electricity.

• Charge and Current — What is actually moving in a wire, how fast it is really going, and why the arrows on every circuit diagram point the wrong way.
• Resistance and Ohm's Law — What slows the electrons down, the one equation that ties the whole topic together, and when it stops being true.
• Series and Parallel Circuits — Two ways of joining components, and why every building in the world is wired one of them.
• Current–Voltage Graphs, LDRs and Thermistors — The shapes four components make on a graph, and two resistors that deliberately refuse to stay the same.
• Voltage as Energy per Charge — What a volt actually is — and why knowing that turns three separate equations into one idea.
• Electrical Power and Energy — Why a wire carrying a current gets hot, how fast a device uses energy, and how to pick a fuse.
• Mains Electricity and Safety — What is different about the electricity in a wall socket, and the four things that stand between it and you.
• Static Electricity — Why rubbing two things together charges them both — and why only one kind of particle is ever responsible.
• Uses and Dangers of Static Electricity — The same effect that makes a jumper crackle can set a fuel tanker alight — and can print a photograph.

Topic 3 · Waves

What a wave is and what it carries, the wave equation, the Doppler effect, the whole electromagnetic spectrum with its uses and dangers, reflection, refraction, total internal reflection and sound.

• What a Wave Is — Something crosses the room and nothing gets to the other side — the idea that makes the rest of the topic possible.
• The Wave Equation — Two equations that connect everything on the previous page — and one of them you could have worked out yourself.
• The Doppler Effect — Why an ambulance changes note as it passes — and why the siren itself never does.
• The Electromagnetic Spectrum — Seven names for one thing — and the two properties that change as you go along it.
• Uses and Dangers of Electromagnetic Radiation — Seven bands, seven jobs — and why the danger rises steadily as you move along the spectrum.
• Reflection and Ray Diagrams — One rule, drawn correctly — and why the image in a mirror is behind it.
• Refraction and Refractive Index — Why light bends entering glass, why it sometimes does not, and how to put a number on it.
• Total Internal Reflection — The angle beyond which light cannot get out at all — and the technology built on it.
• Sound Waves — What is actually travelling when you hear something, what you can and cannot hear, and how to measure how fast it goes.
• Oscilloscopes, Pitch and Loudness — Seeing a sound on a screen — and which feature of the trace corresponds to which thing you hear.

Topic 4 · Energy resources and energy transfers

Energy stores and the transfers between them, efficiency and Sankey diagrams, conduction, convection and radiation, work, power, GPE and KE, and how electricity is actually generated.

• Energy Stores and Transfers — Where energy sits, how it moves, and why it is never used up however much it feels like it.
• Efficiency, Sankey Diagrams and Insulation — Working out what share of the energy did the job you wanted — and why the answer is never all of it.
• Conduction, Convection and Radiation — Three ways energy moves from hot to cold — and the one question that tells them apart.
• Work Done — The precise meaning of a word everybody thinks they already know — and why holding something still is not work at all.
• Gravitational Potential and Kinetic Energy — Two equations, one conversion — and why the square in the second one changes everything.
• Power — Not how much energy, but how fast — and why that is the number people actually buy.
• Generating Electricity — Seven ways of turning something into electricity — and the trade-offs that make the choice hard.

Topic 5 · Solids, liquids and gases

Density and pressure, pressure in fluids, changes of state, specific heat capacity, and the particle model that explains gas pressure and the two gas laws.

• Density — Not how heavy something is, but how much of it is packed into the space it occupies.
• Pressure, and Pressure in Liquids — Why a drawing pin works, why pressure at a point pushes every way at once, and why depth is the only thing that matters underwater.
• Particles and Changes of State — What the particles are doing in each state — and why a boiling pan stays at 100 °C however hard you heat it.
• Specific Heat Capacity — Why the sand burns your feet and the sea is freezing on the same afternoon.
• Gas Pressure and Absolute Zero — Where the pressure of a gas actually comes from, and why the temperature scale has to start somewhere else.
• The Kinetic Theory of Gases — One picture — fast random molecules bouncing off walls — that predicts everything a gas does.
• The Gas Laws — Two equations that put numbers on everything the previous page explained.

Topic 6 · Magnetism and electromagnetism

Magnetic fields and how a current makes one, the motor effect and the left-hand rule, electromagnetic induction, generators and transformers.

• Magnets and Magnetic Fields — Why only repulsion proves you are holding a magnet, and what a field line is actually a picture of.
• Induced Magnetism and Field Patterns — Why an iron nail sticks to a magnet at all, why it never pushes back, and how to plot a field you cannot see.
• Electromagnets — The four pages of Latin that showed a current makes a field — and why that field goes round the wire rather than along it.
• The Motor Effect — Put a current in a magnetic field and something moves — the effect behind every electric motor and every loudspeaker.
• Electromagnetic Induction — Move a magnet near a coil and a voltage appears from nowhere — provided something is changing.
• Transformers — Two coils that never touch, the reason the National Grid runs at 400 000 volts, and why none of it works on a battery.

Topic 7 · Radioactivity and particles

Inside the nucleus: alpha, beta and gamma radiation, nuclear equations, half-life, background radiation, the dangers and uses, and fission and fusion.

• Atomic Structure and Isotopes — A nucleus ten thousand times smaller than the atom around it, and why two atoms of the same element can weigh different amounts.
• Alpha, Beta and Gamma — Three emissions from unstable nuclei, arriving at random — and why the one that is easiest to stop is the one to be most careful with.
• Nuclear Equations — What each kind of decay does to the numbers — and why losing a negative particle makes the charge go up.
• Detecting Radiation and Background — How you measure something invisible, and why the counter clicks even with no source in the room.
• Half-Life — Half of what is left, every time — which is why a radioactive sample never quite runs out.
• Uses and Dangers of Radiation — Choosing a source by its half-life and its penetration — and the difference between being irradiated and being contaminated.
• Nuclear Fission — A single neutron splits a nucleus in half, and the pieces weigh less than what you started with.
• Chain Reactions and Reactors — Two or three neutrons from every split — and the two entirely different jobs a reactor does to them.
• Nuclear Fusion — How the Sun works, and why it is so hard to make it happen anywhere else.

Topic 8 · Astrophysics

Gravity across the universe, orbits, the life cycles of stars, the Hertzsprung–Russell diagram, red-shift and the evidence for the Big Bang.

• The Universe and Gravity — From a moon to the whole universe in five steps, and why your weight would change on the way.
• Orbits — Why anything in orbit is falling, why comets speed up as they arrive, and how to find an orbital speed.
• Star Colour and Temperature — Why blue stars are the hot ones, and how a colour tells you a temperature across the whole galaxy.
• The Life Cycle of Stars — Two endings from one beginning — and the mass a star is born with decides which it gets.
• The Hertzsprung–Russell Diagram — Plot every star by colour and true brightness and they do not scatter — they fall into groups.
• The Big Bang and its Evidence — Two observations that between them decided how the universe began.
• Red-Shift — Every distant galaxy is running away from us, the far ones fastest — and why that does not put us at the centre of anything.

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