Physical Science - Chapter 15 

Thermodynamics

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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

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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

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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

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