Physics S2 Unit 11 Overview

Physics Semester 2 (Spring) Unit 11 Overview

Topic: Thermodynamics
CA State Standards: Physics 3. a-g*

Heat and Thermodynamics
3. Energy cannot be created or destroyed, although in many processes energy is transferred to the environment as heat. As a basis for understanding this concept:

a. Students know heat flow and work are two forms of energy transfer between systems.
b. Students know that the work done by a heat engine that is working in a cycle is the difference between the heat flow into the engine at high temperature and the heat flow out at a lower temperature (first law of thermodynamics) and that this is an example of the law of conservation of energy.
c. Students know the internal energy of an object includes the energy of random motion of the object’s atoms and molecules, often referred to as thermal energy. The greater the temperature of the object, the greater the energy of motion of the atoms and molecules that make up the object.
d. Students know that most processes tend to decrease the order of a system over time and that energy levels are eventually distributed uniformly.
e. Students know that entropy is a quantity that measures the order or disorder of a system and that this quantity is larger for a more disordered system.
f. * Students know the statement “Entropy tends to increase” is a law of statistical probability that governs all closed systems (second law of thermodynamics).
g. * Students know how to solve problems involving heat flow, work, and efficiency in a heat engine and know that all real engines lose some heat to their surroundings.

Prerequisites: Math basic Algebra (Algebra 1)

  1. Essential information:
    1. Heat flows (cold does not)
    2. Heat is work and work is heat!
    3. Temperature scales
    4. Temperature measurement methods and devices
    5. 0th + 3 Laws of Thermodynamics
    6. Entropy
    7. Thermodynamic Efficiency
    8. Specific Heats of materials
    9. Absolute Zero
  2. Historical perspective:
    1. Debate of the ancients – does heat flow or is it cold that flows?
      1. Super Heroes and myths
      2. Scientists resolution (when and how)
    2. Farenheit
      1. On what did Farenheit base his temperature scale?
      2. How did Farenheit measure temperature?
        1. Why was this inaccurate?
    3. Celcius and Centegrade
      1. Definitions, history, rationale
    4. Lord Kelvin, Sir William Thomson, 1st Baron Kelvin
      1. Basis of the Kelvin scale – correct conclusion, wrong reason
      2. Use of the Kelvin scale in thermodynamics
      3. Absolute zero – the strange properties of liquid Helium