14.1 Heat

14.1 Heat

  • One of the most intriguing forms of energy is heat.
    • When in transit, heat only exists and is transferred by a number of different methods.
  • Every aspect of our lives is affected by heat transfer.
    • It explains the chill we feel on a clear night.
    • The methods by which heat is transferred are explored in this chapter.
    • These topics are fundamental and practical, and will often be referred to in the chapters ahead.
  • In Work, Energy, and Energy Resources, we learned that the work done on an object has an effect on the energy of the object.
    • The gas laws show that temperature is related to the average kinetic energy of atoms and Molecules.
    • The internal energy of a thermal system is higher if the temperature is higher.
    • If two objects at different temperatures are brought in contact with each other, energy is transferred from the hotter object to the cooler one until equilibrium is reached and the bodies are at the same temperature.
    • No work is done by either object.
    • Once the temperatures are equal, the transfer of energy ceases.
  • The heat is often confused with the temperature.
    • When we actually mean that the temperature was high, we can say the heat was unbearable.
    • The difference between heat and temperature is that heat is a form of energy.
    • We are sensitive to the flow of heat, not the temperature.
  • The SI unit of J is due to the fact that heat is a form of energy.
  • Since mass is usually specified in kilograms, kilocalorie is often used.
    • Food calories are actually kilo calories, which is a fact not easily determined from package labeling.
  • The soft drink and ice are not in thermal equilibrium.
    • When the soft drink and ice are allowed to interact, energy is transferred until they reach the same temperature.
  • The difference in temperature causes heat transfer.
    • Since the soft drink and ice are in contact with the surrounding air and bench, the equilibrium temperature will be the same.
  • The temperature of a substance can be changed by doing work.
    • Energy can be transferred into or out of a system.
    • The fact that heat is a form of energy was established by this realization.
    • The same work is needed to produce heat transfer.
  • The equation is considered the conversion between two units of energy.
  • Joule's experiment established the equivalence of heat and work.
  • One of Joule's most famous experimental setups shows the mechanical equivalent of heat.
    • It helped establish the principle of conserve energy by showing that heat and work can produce the same effects.