Led by Ludwig Boltzmann Simulacrum
About this course
The particle model is the idea that matter is made of atoms and molecules, that these particles are in constant motion, and that the bulk behaviour we observe — density, changes of state, heat capacity, gas pressure — follows from the motion and arrangement of the particles. It is perhaps the single most productive idea in physics. It lets an engineer design a submarine to withstand pressure at depth, and it explains why it is difficult to make a good cup of tea on top of a mountain.
This course follows AQA specification 8463, section 4.3 in full. Five simulacra take the modules in turn. Dalton opens with density and states of matter — he is the founder of the atomic theory in its modern form. Avogadro takes internal energy, where his molecular hypothesis gives the right picture of where energy is stored. Gay-Lussac takes latent heat, working from the gas-behaviour side. Boltzmann takes particle motion in gases — kinetic theory is his masterwork. Boyle closes the course with the law that bears his name.
Required Practical 5 (density of solids and liquids) is treated within Module 1. The experiment to measure the latent heat of fusion of water is within Module 3. The Higher-Tier-only content on work done on a gas is within Module 5, which is also physics-only (triple science) — it can be studied or skipped without disrupting the course's narrative.
Led by John Dalton Simulacrum
The question
Why is a block of iron denser than a block of wood, and why is the same water light as steam and heavy as ice?
Outcome
The student can apply the density equation, draw the particle arrangement for each state of matter, explain differences in density in terms of particle arrangement, describe all six changes of state with mass conservation, and carry out Required Practical 5 for regular solids, irregular solids, and liquids. (AQA 4.3.1.1, 4.3.1.2)
Led by Amedeo Avogadro Simulacrum
The question
When you heat a substance, what actually happens to the atoms inside it?
Outcome
The student can define internal energy, explain what heating does at the particle level, apply ΔE = mcΔθ correctly, and connect the molecular picture to the numerical value of specific heat capacity. (AQA 4.3.2.1, 4.3.2.2)
Led by Joseph Louis Gay-Lussac Simulacrum
The question
Why does boiling water stay at 100 °C no matter how much heat you put in, even though the kettle is still pouring energy into it?
Outcome
The student can apply E = mL, interpret heating and cooling graphs including plateaus at phase changes, distinguish specific heat capacity from specific latent heat, and perform an experiment to measure the latent heat of fusion of water. (AQA 4.3.2.3)
Led by Ludwig Boltzmann Simulacrum
The question
What IS temperature, at the level of the particles that make up a gas?
Outcome
The student can explain the motion of gas molecules, relate gas temperature to the average kinetic energy of its molecules, and reason qualitatively about the pressure of a gas held at constant volume when the temperature changes. (AQA 4.3.3.1)
Led by Robert Boyle Simulacrum
The question
If you squeeze a sealed syringe, why does the air inside push back — and what happens to the temperature?
Outcome
The student can state Boyle's Law and apply pV = constant to both compression and expansion, use the particle model to explain qualitatively why reducing volume raises pressure, and (Higher Tier) explain how doing work on a gas raises its temperature. (AQA 4.3.3.2, 4.3.3.3)