Two identical metal mugs, Mug PPP and Mug QQQ, each fitted with a lid, are filled with equal volumes of hot water.
The temperature of the water in each mug is recorded every minute.
State which mug has the larger temperature decrease over the first 5 minutes. Explain your answer.
Eventually, the temperature of the water in Mug PPP stops falling and remains constant at room temperature. State, in terms of energy transfers, why the temperature remains constant.
The experiment is repeated but with the lids removed from both mugs. State the name of an additional process of thermal energy transfer that now occurs from the open top of each mug.
A metal spoon and a plastic spoon of identical dimensions are placed into a bowl of very hot soup. Explain, in terms of particles, why there is a much greater rate of transfer of thermal energy along the metal spoon than along the plastic spoon.
301 exam-style questions on CIE IGCSE Physics 2.3 Transfer of thermal energy, covering 2.3.1a Thermal conductors and thermal insulators, 2.3.1b Explaining thermal conduction, 2.3.2 Convection, 2.3.3a Thermal radiation, 2.3.3b Surface colour and texture, 2.3.3c Rate of emission and absorption of radiation, and 2.3.4 Consequences of thermal energy transfer. Each one has a worked solution and a mark scheme showing where the marks go.