CIE IGCSE Physics Notes
Chapter 2 Thermal Physics
2.1 Kinetic particle model of matter
▪ Matter exist in one of four different states.
State Characteristics
Solid • Fixed shape and volume.
• Strong forces of attraction
between particles.
• Have a fixed pattern (lattice)
• Atoms vibrate but cannot change position.
Liquid • Fixed volume but changes shape depending on
container
• Weaker attractive forces that solids
• No fixed pattern
• Particles slide past each other
Gases • No fixed shape volume, gases fill up their
containers
• Almost no intermolecular forces
• Particles are far apart, and move quickly,
gases spread out to fill up the container and
exert equal pressure on all surfaces.
• They collide with each other and bounce in all
directions.
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, CIE IGCSE Physics Notes
▪ Matter can change from solid to liquid via melting and liquid to solid via freezing.
▪ These changes occur at the melting point.
▪ Liquid can also change to gas via boiling and gas to liquid via condensing.
▪ These occur at the boiling point.
• Molecules in a gas move around randomly and very quickly.
• The temperature of a gas is related to the average kinetic energy of the
molecules.
• The higher the KE of the molecules, the higher its temperature.
Page | 2
Senpaicorneer.com
Chapter 2 Thermal Physics
2.1 Kinetic particle model of matter
▪ Matter exist in one of four different states.
State Characteristics
Solid • Fixed shape and volume.
• Strong forces of attraction
between particles.
• Have a fixed pattern (lattice)
• Atoms vibrate but cannot change position.
Liquid • Fixed volume but changes shape depending on
container
• Weaker attractive forces that solids
• No fixed pattern
• Particles slide past each other
Gases • No fixed shape volume, gases fill up their
containers
• Almost no intermolecular forces
• Particles are far apart, and move quickly,
gases spread out to fill up the container and
exert equal pressure on all surfaces.
• They collide with each other and bounce in all
directions.
Page | 1
Senpaicorneer.com
, CIE IGCSE Physics Notes
▪ Matter can change from solid to liquid via melting and liquid to solid via freezing.
▪ These changes occur at the melting point.
▪ Liquid can also change to gas via boiling and gas to liquid via condensing.
▪ These occur at the boiling point.
• Molecules in a gas move around randomly and very quickly.
• The temperature of a gas is related to the average kinetic energy of the
molecules.
• The higher the KE of the molecules, the higher its temperature.
Page | 2
Senpaicorneer.com
