Effects of Temperature - Physical properties of materials are influenced by temperature, including phase, density, solubility, vapor pressure, electrical conductivity, hardness, wear resistance, thermal conductivity, corrosion resistance, and strength. - Chemical reactions are affected by temperature, including the rate and extent of reactions. - Thermal radiation emitted from an object's surface is dependent on temperature. - Air temperature has an impact on all living organisms. - The speed of sound in a gas is proportional to the square root of the absolute temperature.

Temperature Scales - The Celsius scale (°C) is commonly used worldwide and is based on the freezing and boiling points of water at sea level. - The Kelvin scale (K) is an absolute scale used in scientific applications, with its zero point at absolute zero. - The Fahrenheit scale (°F) is primarily used in the United States, with water freezing at 32°F and boiling at 212°F.

Absolute Zero and Absolute Scales - Absolute zero is the lowest possible temperature, where no energy can be extracted as heat. - Matter at absolute zero contains no macroscopic thermal energy but still possesses quantum-mechanical zero-point energy. - Absolute zero is defined as 0K, which is equal to -273.15°C or -459.67°F. - The Kelvin scale is an absolute temperature scale that is independent of specific thermometric substances and thermometer mechanisms. - The temperature of a body in thermodynamic equilibrium is always positive relative to absolute zero. - The Kelvin scale is widely used in science and technology. - Lord Kelvin also developed a thermodynamic temperature scale that relates to macroscopic thermodynamic concepts, including entropy. - This scale has a reference temperature at the triple point of water.

Empirically based thermometers - Length of a column of mercury in a glass-walled capillary tube is dependent on temperature. - Mercury-in-glass thermometer is valid only within convenient temperature ranges. - Some materials, like water, contract with temperature increase over a specific range. - Materials near their phase-change temperatures are not useful as thermometric materials. - Empirically based thermometers can be re-calibrated using theoretical physical reasoning.

Measurement and Theory of Temperature - The spectrum of black-body radiation provides an accurate temperature measurement. - Wiens displacement law relates the frequency of maximum spectral radiance to temperature. - The spectrum of noise-power produced by an electrical resistor can measure temperature. - Johnson noise is directly proportional to temperature, resistance, and noise bandwidth. - Accurate temperature measurement can be achieved using known values of resistance. - Classical mechanics explains macroscopic phenomena through microscopic particles. - The equipartition theorem of kinetic theory states that each degree of freedom of a particle has an average kinetic energy of /2. - The speed of sound in a gas can be calculated from the molecular character, temperature, pressure, and Boltzmann constant. - The average kinetic energy of microscopic particles can be measured by allowing them to escape from the system through a small hole. - Temperature is a principal quantity in the study of thermodynamics. - Temperature is an intensive variable in thermodynamics. - Real-world bodies are often not in thermodynamic equilibrium and not homogeneous. - Thermodynamics has conjugate variables such as pressure, volume, temperature, entropy, chemical potential, and particle number. - Hotness means that suitably given empirical thermometers with numerical scale readings will agree on which body is hotter or if they have the same temperature. - The relation between numerical scale readings of thermometers must be strictly monotonic.