1
Cambridge IGCSE
Physics
Revision Guide 2024
Unit 2
Mohammed Ali
[Physics with Mo Ali]
Cambridge IGCSE Physics Revision Guide by Mo Ali – Unit 2
, 2
Kinetic Particle Model of Matter
1 Know the distinguishing properties of solids, liquids and gases
2 Know the terms for the changes in state between solids, liquids and gases (gas to solid and solid to gas transfers are
not required)
3 Describe the particle structure of solids, liquids and gases in terms of the arrangement, separation and motion of the
particles, and represent these states using simple particle diagrams
4 Know that the forces and distances between particles (atoms, molecules, ions and electrons) and the motion of the
particles affects the properties of solids, liquids and gases
5 Describe an increase in temperature of an object in terms of an increase in the average kinetic energies of all of the
particles in the object
6 Describe the relationship between the motion of particles and temperature, including the idea that there is a lowest
possible temperature (−273 °C), known as absolute zero, where the particles have least kinetic energy
7 Convert temperatures between kelvin and degrees Celsius; recall and use the equation T (in K) = θ (in °C) + 273
8 Describe melting and boiling in terms of energy input without a change in temperature
9 Know the melting and boiling temperatures for water at standard atmospheric pressure
10 Describe condensation and solidification in terms of particles
11 Describe evaporation in terms of the escape of more energetic particles from the surface of a liquid
12 Know that evaporation causes cooling of a liquid
13 Describe the differences between boiling and evaporation
14 Describe how temperature, surface area and air movement over a surface affect evaporation
15 Explain the cooling of an object in contact with an evaporating liquid
States of Matter
Solid Liquids Gases
Shape and Volume Fixed shape and a fixed volume Fixed volume but not a fixed No fixed shape nor volume
shape
Diagram
Spacing and Molecules have very small Molecules have small spacing Molecules are all far apart with
Arrangement spacing between them. between them. Molecules are very large spacing between
Molecules have regular randomly arranged (no fixed them. There is no arrangement.
arrangement. pattern).
Motion Molecules vibrate about a fixed Molecules slide over each other Molecules move very fast, free
position. randomly. and randomly
Attractive Forces Very strong bonds between the Strong bonds between the Very weak bonds between the
(Bonds) molecules. molecules molecules
Defining Temperature: Average Kinetic Energy of the molecules in a substance (Units: ℃, K)
If the temperature of an object increases, the molecules move faster. If temperature decreases, the molecules move
slower.
Defining Absolute Zero: the lowest possible temperature at which particles have the least kinetic energy (-273℃)
Changing from ℃ to K: 𝑻 (𝒊𝒏 𝑲) = 𝜽 (𝒊𝒏 ℃) + 𝟐𝟕𝟑
Cambridge IGCSE Physics Revision Guide by Mo Ali – Unit 2
Cambridge IGCSE
Physics
Revision Guide 2024
Unit 2
Mohammed Ali
[Physics with Mo Ali]
Cambridge IGCSE Physics Revision Guide by Mo Ali – Unit 2
, 2
Kinetic Particle Model of Matter
1 Know the distinguishing properties of solids, liquids and gases
2 Know the terms for the changes in state between solids, liquids and gases (gas to solid and solid to gas transfers are
not required)
3 Describe the particle structure of solids, liquids and gases in terms of the arrangement, separation and motion of the
particles, and represent these states using simple particle diagrams
4 Know that the forces and distances between particles (atoms, molecules, ions and electrons) and the motion of the
particles affects the properties of solids, liquids and gases
5 Describe an increase in temperature of an object in terms of an increase in the average kinetic energies of all of the
particles in the object
6 Describe the relationship between the motion of particles and temperature, including the idea that there is a lowest
possible temperature (−273 °C), known as absolute zero, where the particles have least kinetic energy
7 Convert temperatures between kelvin and degrees Celsius; recall and use the equation T (in K) = θ (in °C) + 273
8 Describe melting and boiling in terms of energy input without a change in temperature
9 Know the melting and boiling temperatures for water at standard atmospheric pressure
10 Describe condensation and solidification in terms of particles
11 Describe evaporation in terms of the escape of more energetic particles from the surface of a liquid
12 Know that evaporation causes cooling of a liquid
13 Describe the differences between boiling and evaporation
14 Describe how temperature, surface area and air movement over a surface affect evaporation
15 Explain the cooling of an object in contact with an evaporating liquid
States of Matter
Solid Liquids Gases
Shape and Volume Fixed shape and a fixed volume Fixed volume but not a fixed No fixed shape nor volume
shape
Diagram
Spacing and Molecules have very small Molecules have small spacing Molecules are all far apart with
Arrangement spacing between them. between them. Molecules are very large spacing between
Molecules have regular randomly arranged (no fixed them. There is no arrangement.
arrangement. pattern).
Motion Molecules vibrate about a fixed Molecules slide over each other Molecules move very fast, free
position. randomly. and randomly
Attractive Forces Very strong bonds between the Strong bonds between the Very weak bonds between the
(Bonds) molecules. molecules molecules
Defining Temperature: Average Kinetic Energy of the molecules in a substance (Units: ℃, K)
If the temperature of an object increases, the molecules move faster. If temperature decreases, the molecules move
slower.
Defining Absolute Zero: the lowest possible temperature at which particles have the least kinetic energy (-273℃)
Changing from ℃ to K: 𝑻 (𝒊𝒏 𝑲) = 𝜽 (𝒊𝒏 ℃) + 𝟐𝟕𝟑
Cambridge IGCSE Physics Revision Guide by Mo Ali – Unit 2
