Thermal Unit Concepts

Here are the overall concepts to be covered in the Thermal Energy Unit:

• Heat, Temperature and Thermal Energy
• Phases Changes
• Power and Thermal Energy
• Heat Engines
• Efficiency
• Conduction, Convection and Radiation (calculation and concepts)
• Laws of Thermodynamics

\Vocabulary
•Energy              Kinetic Energy    Thermal Energy    Specific Heat
•Absolute Zero   Calorie                Power                   Thermal Laws
•Conduction       Convection          Radiation              Insulation
•Insulator            Conductor           Pressure                Volume
•Temperature      R-value               Radiator                Boiler
•Condenser         Engine                Turbine                 Compressor
•Piston                Intake                 Exhaust               Isothermal
•Combustion      Heat Engine       Generator              Steam Engine
•Entropy             Fluid                  Latent Heat          Thermal Equilibrium
•Melting             Freezing            Sublimation          Evaporation
•Vaporization     Condensation    Adiabatic             Thermal Expansion
•Combustion      Heat Death       Order                   Disorder
•Enthalpy           Carnot              Efficiency            Heat of Fusion/Vaporization

Relationships

•Understand the relationship between temperature, heat, and thermal energy.
•3 Thermal Laws: Understand and be able to provide examples.
    –1st Law: Conservation of Energy (delQ+/_ del W = 0)
     –2nd Law: Heat flows naturally from hot to cold; it will not spontaneously move from cold to hot.
     –2nd/3rd Law: Entropy -natural Processes tend to move toward a state of greater disorder
     - 2nd/3rd Law  no device is possible whose sole effect is to transform a given amount of heat completely into work.

•Gas Laws: Understand the relationship between pressure, volume and temperature. (pV~T)
•Heat flow and changes of state.
•Similarities in heat engines, heating systems, and cooling systems.
•Relationship between the rate of cooling and the temperature difference between two bodies
•Relationships between Power Output through Conduction/Radiation and other properties of material.

Applications

•Thermodynamic explanations for climate.
•How heat moves. Know examples and applications.
•Used for Conductors and Insulators
•Considerations in using insulators
•Examples and diagrams of insulated systems (double-pane window, vacuum bottle, etc.)
•How each of the listed heating systems functions and where each uses conduction, convection and radiation.
•How and why a steam engine and its components operate.
•How different energy sources are used to generate electricity.
•The steps in the 4-stroke internal combustion engine.
•How thermal energy drives plate tectonics and the weather
•The affect of thermal pollution on the surrounding environment
•The role of thermodynamics in stellar evolution

Problems

•You should be able to apply and calculate the following equations.

•Temperature Conversions
     • K= C +273      C=5/9(F-32)      F= 9/5C +32 
•Heat Flow: Q = mcDT.
     •Q-Change in Thermal Energy (joules, J)
     •m- Mass (Kg)
     •c- Specific Heat (J/Kg*C)
     •DT –Change in temperature (Final – Initial) (C) 

•Power: P=Q/t or t=Q/P

     •P-Power (Watts, W) 

     •t- Time (seconds)
    •Q-Change in Thermal Energy (joules, J)

•Change in State Q=ml 

    •Q-Change in Thermal Energy (joules, J)

     •m- Mass (Kg)
     •l- latent heat (J/Kg)
Entropy: DS = Q/T

Also; efficiency (Carnot and standard), final temperature problems, conservation problems, radiation and conduction problems.