Define the lower fixed point and the upper fixed point used to calibrate the Celsius scale. For each fixed point, specify the corresponding substance, the state change, and the temperature value in ∘C^\circ\text{C}∘C under standard atmospheric pressure.
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.