An athlete finishes a long run on a warm, breezy day and notices that they feel cold as their sweat evaporates.
Why does the evaporation of sweat cause their skin to cool?
The less energetic water molecules in the sweat escape quickly into the air.
The more energetic water molecules in the sweat are prevented from escaping by the wind.
The sweat acts as a thermal conductor, drawing cold air directly toward the skin.
The higher-energy water molecules in the sweat escape, removing thermal energy from the skin.
528 exam-style questions on CIE IGCSE Physics 2.2 Thermal properties and temperature, covering 2.2.1 Thermal expansion of solids, liquids and gases, 2.2.2a Internal energy and temperature, 2.2.2b Specific heat capacity, 2.2.3a Melting, boiling, condensation and solidification, 2.2.3b Evaporation, and 2.2.3c Cooling by evaporation. Each one has a worked solution and a mark scheme showing where the marks go.