P2.2.1 Thermal expansion of solids, liquids and gases

Describe the thermal expansion of solids at constant pressure

• Solids: expands slightly

  • When heated, atoms vibrate faster about their fixed position

  • Relative increase in volume expansion is small

Describe the thermal expansion of liquids at constant pressure

• Liquids: expands more than solids

  • When heated atoms vibrate, move around and get slightly further apart

  • Volume of liquids increases as temperature increases

Describe the thermal expansion of gases at constant pressure

• Gases: expands significantly

  • Molecules within gases are further apart and have weak intermolecular forces

  • When heated, molecules move faster than in a solid or liquid

Explain some of the everyday applications and consequences of thermal expansion

• Solids: expansion gaps allow railway tracks to expand, without these gaps the railway track would crack

• Liquids: liquid thermometers have alcohol or mercury that expand or contract with changes in temperature

• Gases: hot air balloons are heated which causes the expansion of the air, which leads to expansion of the balloon