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Essential Question:
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Analyzing Video s for Physics
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Lesson 1
Key Concept: The 1st
law of Thermodynamics.
Purpose: Show how
the first law in combination with perfect gas laws can be used to
evaluate idealized processes.
Discussion questions:
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In all of science, what principle
comes closest to absolute truth?
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Bob has a solar panel covering 2
square meters. He buys a lens with the same area and uses it to
focus the sun's light on a smaller panel with 0.2 square meters. Will he improve the electrical output from his solar cell
system using the lens. (assume solar cell efficiency remains
constant with temperature.)
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Why is hydrogen not a true energy
source?
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Does a ceiling fan heat or cool a
room?
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Heat
engines and heat pumps
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Outline the concept of the
heat engine and the heat pump.
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Draw and annotate
schematic diagrams of a heat engine and a heat pump.
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Define the term
thermal
efficiency of a heat engine 2 ways, mathematically and in English language.
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Draw and annotate the
Carnot cycle on a p-V diagram.
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State what the Carnot
Cylce represents.
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State Carnot’s theorem.
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State an expression for
the efficiency of a Carnot engine in terms of the temperatures of the two
reservoirs.
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Discuss the possibility of
changing the thermal efficiency by altering the reservoir temperatures.
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Solve problems involving
heat engines and heat pumps.
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Lesson 2 Essential Question:
Could the engine in a car convert 100% of the energy in the gasoline
it burns into usable work?
Key Concept:
Introduce the basics required for evaluating new energy related
inventions.
Discussion questions:
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Would a friction free engine in a car be able to
convert 100% of the energy in gasoline into useful work?
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Will a heat pump work as
well in Minnesota as in Greenville SC?
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Second Law
of Thermodynamics and Entropy
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State that heat can be
completely converted to work in a single process, but that continuous
conversion of heat into work requires a cyclical process and the rejection of
some heat.
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State the Kelvin–Planck
formulation of the
2nd law of thermodynamics.
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It is sufficient for
students to acknowledge the impossibility of constructing a heat engine
operating in a cycle that does not transfer energy to a cold reservoir.
Teachers might like to show that if this were possible then it would imply
that energy can be transferred spontaneously from a cold to a hot reservoir.
This leads to the Clausius statement of the 2nd law.
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Analyze situations in
terms of whether they are consistent with the first and/or second law.
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State that entropy is a
system property that expresses the degree of disorder in the system.
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State the second law in
terms of entropy changes. A statement that the overall entropy of the
universe is increasing will suffice.
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Discuss examples of
natural processes in terms of entropy changes.
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Students should understand
that although local entropy can decrease, any process will increase the total
entropy of the system and surroundings.
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Discuss the idea of energy
degradation in terms of the second law.
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Be as one with the relevant equations
HL thermodynamics
equations in the IB Physics Data Booklet.
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Lesson 3 Essential Question:
Is the universe winding down?
Key Concept: The 2nd
Law of Thermo and entropy
Purpose:
Introduce the basics required for evaluating new energy related
inventions.
Discussion questions:
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Does the 2nd Law of Thermo
preclude the possibility of biological evolution?
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