An athlete covered in sweat feels cold when they stand in front of an electric fan, even though the room is warm.
Why does the athlete feel cold?
The sweat on their skin does not evaporate fast enough to keep them warm.
The lower-energy sweat molecules on their skin escape quickly.
The sweat evaporates quickly, absorbing thermal energy from the skin.
The fan cools the surrounding air, which then cools the wet 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.