What this topic covers
Temperature and its measurement: Concept of temperature as degree of hotness or coldness. Construction and graduation of a simple thermometer. Properties of thermometric liquids. Specific thermometers to be treated: Constant-volume gas thermometer, resistance thermometer, thermocouple, liquid-in-glass thermometer (including maximum and minimum thermometer and clinical thermometer), pyrometer to be mentioned. Celsius and Absolute scales of temperature, Kelvin and degree Celsius as units. Effects of heat on matter (Kinetic theory explanation): Rise in temperature, change of phase state, expansion, change of resistance, change of colour, thermionic emission, change in chemical properties. Thermal expansion: Linear, area and volume expansivities (qualitative and quantitative treatment). Consequences and application of expansions in buildings and bridges, bimetallic strips, thermostat, over-head cables (sagging), and railway lines (buckling). Real and apparent expansion of liquids. Anomalous expansion of water. Unit of expansivity: Per Kelvin (K⁻¹). Heat transfer: Conduction, convection and radiation. Use of the kinetic theory to explain modes of heat transfer. Simple experimental illustrations. Explanation of land and sea breezes, ventilation, and applications in cooling devices. The vacuum flask. The gas laws: Boyle's law, Charles' law, pressure law and general gas law. Verification using simple apparatus. Use of the kinetic theory to explain the laws. Simple problems may be set. Mention of safety air bags in vehicles. Measurement of heat energy: Concept of heat capacity and specific heat capacity. Use of the method of mixtures and the electrical method to determine the specific heat capacities of solids and liquids. Land and sea breezes related to the specific heat capacity of water and land. Unit of specific heat capacity: Jkg⁻¹K⁻¹. Latent heat: Concept and types of latent heat. Melting point and boiling point: Determination, effects of impurities and pressure, application in pressure cooker. Specific latent heat of fusion and of vaporization: Use of method of mixtures and electrical method to determine for ice and steam. Applications in refrigerators and air conditioners. Unit of specific latent heat: Jkg⁻¹. Evaporation and boiling: Effect of temperature, humidity, surface area and draught on evaporation. Vapour and vapour pressure: Explanation, demonstration using simple experiments. Saturated vapour pressure and its relation to boiling. Humidity, relative humidity and dew point: Measurement of dew point and relative humidity. Estimation of atmospheric humidity using wet and dry-bulb hygrometer. Humidity and the weather: Formation of dew, fog and rain.