Physical Science - Chapter 15 

Thermodynamics

15A Temperature

• $Temperature$: the measure of the hotness or coldness of a substance; proportional to the average kinetic energy of the particles within the substance
• $Thermometric Property$: any property that changes predictably with changes in temperature
• $Thermal Expansion$: the property of many materials to increase in volume when heated and contract when cooled
• Temperature Scales
  • Fahrenheit
  • Celsius
  • Kelvin

15B Heat

• $Heat$: movement of thermal energy from an area of higher temperature to one of lower temperature
• Energy Transfer
  • $Conduction$: movement of electric charge or thermal energy through an object or from object to object through direct contact
  • $Convection$: movement of thermal energy as fluids move
  • $Radiation$: movement o energy in the form of electromagnetic waves
• $Thermal Conductor$: a material through which thermal energy moves easily
• $Thermal Insulator$: a material through which thermal energy does not easily move
• Measuring Heat
  • $Specific heat$: the energy required to raise the temperature of 1 g of a substance 1 degree Celsius
  • $Calorimeter$: a device that enables scientists to measure the thermal energy transferred in reactions and between systems
• Energy Transfer By Heating
  • Heating ice
  • Melting ice
  • Heating water
  • Vaporizing water
  • Heating steam

15C Thermodynamics

• $Thermodynamics$: the study of thermal energy and heat and how they relate to work and other forms of energy
• $Caloric Theory$: the now-obsolete theory that stated that heat was an invisible self-repelling fluid
• Laws of Thermodynamics:
  • $First Law of Thermodynamics$: the law that states that energy cannot be created or destroyed but only transferred between objects or transformed; also known as law of conservation of energy
  • $Second Law of Thermodynamics$: the law that states that energy can flow from a colder object to a warmer object only if something does work
  • $Third Law of Thermodynamics$: the law that states that entropy would be at its minimum value at absolute zero. Therefore, absolute zero can never be achieved