CAIE IGCSE Physics Cooling Objects by Evaporation
Practise explaining how an evaporating liquid cools skin, cloth or a container by taking energy from the object as higher-energy particles escape.
- Syllabus
- 2026–2028
- Course
- Physics 0625
Practise explaining how an evaporating liquid cools skin, cloth or a container by taking energy from the object as higher-energy particles escape.
Fig. 3.1 and Fig. 3.2 show how a puddle of water changes on a warm windy day.

Fig. 3.1

Fig. 3.2
Explain, in terms of molecules, how sweating helps to cool your body on a hot day.
Any three from:
- (thermal) energy in the skin / body transferred to (molecules of) sweat
- These molecules (have enough KE to) escape from the skin / become water vapour
- Leaving behind molecules with lower energy
- Which leaves the skin / body at a lower temperature
B3