Matter

What Matter covers

Matter is examined in Paper 5 (Physics). It covers how the atomic model changed, and the structure of the atom; the size of atoms, and defining density; density of the states of matter, and density calculations; conservation of mass in changes of state; heating a system, and specific heat capacity; calculations with specific heat capacity and latent heat; and gas molecules, temperature and pressure.

The 7 subtopics

Each one has its own page.

• How the atomic model changed, and the structure of the atomThe Thomson, Rutherford and Bohr models and Chadwick's neutron, the alpha scattering experiment of Geiger and Marsden and what it showed, the nuclear atom and its size, why models change, and hypotheses, testing theories, peer review and publishing results.Open →
• The size of atoms, and defining densityThe typical size of atoms and small molecules in standard form and nanometres, order-of-magnitude estimates, the symbols for much less than, much greater than and approximately, and density as mass per unit volume, its units and how it compares between objects.Open →
• Density of the states of matter, and density calculationsThe particle arrangements in solids, liquids and gases and how they explain differences in density, why ice floats, rearranging density = mass ÷ volume for calculations, and measuring the density of regular and irregular solids and of liquids with a balance, callipers, eureka can and measuring cylinder.Open →
• Conservation of mass in changes of stateThe names of the changes of state including sublimation, why mass is conserved when ice melts or a puddle evaporates, what a physical change is and how it differs from a chemical change, and why a change of state makes no new substance.Open →
• Heating a system, and specific heat capacityThe two effects of heating a system, internal energy and particle speed, why the temperature holds steady during a change of state, specific heat capacity and the specific latent heats of fusion and vaporisation with their units and when each is used, and the flat section of a cooling curve for stearic acid.Open →
• Calculations with specific heat capacity and latent heatThe relationship between energy, mass, specific heat capacity and temperature change, worked examples finding each quantity, the energy needed to change state, and a combined melting and warming calculation.Open →
• Gas molecules, temperature and pressureHow gas molecules move, what temperature and pressure mean in terms of molecules, what a closed system is, and why heating or cooling a sealed rigid container changes its pressure.Open →

What you need to know

Answer each one before you reveal it.

Take Matter further

The same content, four other ways.

Commonly confused

Pairs that lose marks when they are blurred together.

• Specific heat capacity vs Specific latent heat

  Specific heat capacity: energy needed to raise the temperature of 1 kg of a substance by 1 °C. Specific latent heat: energy needed to change the state of 1 kg with no temperature change.

• Specific latent heat of fusion vs Specific latent heat of vaporisation

  Specific latent heat of fusion: energy needed to melt 1 kg from solid to liquid at constant temperature. Specific latent heat of vaporisation: energy needed to turn 1 kg from liquid to gas at constant temperature.

• Physical change vs Chemical change

  Physical change: a process making no new substance, reversed to give the material back. Chemical change: a process forming new substances that cannot be undone by reversing it.

Questions from this topic

Each one with the model answer underneath.

1. 1

   What did Thomson's model of the atom describe, and which discovery led him to it?

   Model answer

   It described the atom as a ball of positive charge with tiny negative electrons spread through it, and he proposed it after discovering the electron.

2. 2

   In the alpha particle scattering experiment, what was fired at what?

   Model answer

   A narrow beam of alpha particles was fired at an extremely thin sheet of gold foil.

3. 3

   Who carried out the alpha particle scattering measurements that Rutherford interpreted?

   Model answer

   Geiger and Marsden, who counted the alpha particles arriving at different angles after passing through the foil.

4. 4

   What were the two surprising results of the alpha particle scattering experiment?

   Model answer

   Almost all the alpha particles went straight through the foil, but a very small number were deflected through large angles or came straight back.

5. 5

   What did Rutherford conclude about the atom from the scattering results?

   Model answer

   That the atom is mostly empty space, with almost all its mass and all its positive charge in a tiny central nucleus.

6. 6

   Why could the earlier model of the atom not explain the alpha scattering results?

   Model answer

   Positive charge spread thinly through the whole atom could never repel a fast alpha particle strongly enough to turn it back, so the charge had to be concentrated.

What is inside Levo

Six ways to work the same material.

Matter revision questions

What does Matter cover in OCR GCSE Combined Science Physics?

7 subtopics: how the atomic model changed, and the structure of the atom, the size of atoms, and defining density, density of the states of matter, and density calculations, conservation of mass in changes of state, heating a system, and specific heat capacity, calculations with specific heat capacity and latent heat and gas molecules, temperature and pressure. Each one has its own page with questions and model answers.

How is Matter organised?

By the OCR J250 specification, subtopic by subtopic, so it matches the order you are taught it in.