Analyze systems, properties, work, heat, first law, second law, cycles, and practical energy devices.
Course outline only for now. Full chapter-level lessons are still in progress. Use this page for readiness, concepts, worked-example format, practice, review, and portfolio direction. Complete course contents are live today for Math, Physics, and Statics.
01
Readiness check
Before starting, confirm the prerequisite habits.
Define a system boundary.
Read property units.
Use sign convention for heat and work.
Distinguish state properties from path quantities.
0 or 1 weak itemContinue, but slow down at the worked example.
2 weak itemsReview the foundation page linked in the roadmap before solving practice problems.
3 or more weak itemsStep back to prerequisites; this module depends on them.
02
The core idea
Build energy balances for closed and open systems and interpret the physical result.
Every thermodynamics problem starts by drawing the boundary, deciding whether mass crosses it (open vs. closed), and tracking energy as heat, work, or flow; the bookkeeping, not the formula, is the skill.
W = P Delta V
Works when: the boundary is drawn, the process path (constant P, V, T, or adiabatic) is named, and each energy transfer has a sign.
Breaks down when: you apply Q = m c Delta T or W = P Delta V without first asking whether the process is actually constant-pressure, reversible, or steady.
Figure 1. Concept model for Thermodynamics. The figure names inputs, computed variables, geometry, and result.
Figure 2. Worked problem setup: A gas expands at constant pressure 200 kPa from 0.030 m^3 to 0.050 m^3 while receiving 4 kJ of heat. Find boundary work and change in internal energy.Figure 3. Calculation model. The result follows from the model, units, and reasonableness check.
A gas expands at constant pressure 200 kPa from 0.030 m^3 to 0.050 m^3 while receiving 4 kJ of heat. Find boundary work and change in internal energy.
Problem A gas expands at constant pressure 200 kPa from 0.030 m^3 to 0.050 m^3 while receiving 4 kJ of heat. Find boundary work and change in internal energy.
Given and find P = 200 kPa, V1 = 0.030 m^3, V2 = 0.050 m^3, Q = 4 kJ. Find: W and Delta U.
Assumptions Idealized model, consistent units, and no hidden effects outside the stated scope.
Step Boundary work W = P(V2 - V1).
Step W = 200 kPa times 0.020 m^3 = 4 kJ.
Step Closed-system first law gives Delta U = Q - W = 0 kJ.
Step Check: kPa*m^3 equals kJ.
Conclusion W = 4 kJ, Delta U = 0. Carry this result into the design decision, not just into the answer box.
05
Misconceptions and diagnostics
Mistake
Symptom
Diagnostic question
Correction
Confusing heat and temperature
Treats Q as something stored in the gas
Is this a state you can point to, or a transfer crossing the boundary?
Heat and work are path transfers; only U, T, P, V are states.
Sign convention drift
Delta U comes out with the wrong sign
Is work done by the system positive in your convention?
Fix one convention (Q in +, W out +) and label it on the diagram.
Ignoring the process path
Uses W = P Delta V for a non-constant-pressure process
Is pressure actually constant along this path?
Match the work integral to the real P-V path.
06
Practice ladder
Level 1: direct skill
Redo the worked example with one changed input. Predict the trend before calculating.
Check yourself
The trend must match the governing relation: W = P Delta V.
Level 2: mixed concept
Draw the model from memory, label knowns and unknowns, then write the first equation without looking.
Check yourself
Your first equation should connect the model to W, Delta U.
Level 3: independent problem
Create a similar problem from a real object near you. State assumptions, solve it, and include a reasonableness check.
Check yourself
A valid solution has a sketch, given/find list, governing relation, units, and a conclusion.
Level 4: transfer task
Turn the result into a design decision: what would you change if the output missed its target by 25 percent?
Check yourself
Name the design variable with the strongest influence and justify it from the equation.
07
Working with AI, and proving it yourself
Useful AI role
Ask for a critique of assumptions, units, diagram labels, and missing checks after you have attempted the solution.
Do not outsource
Do not paste the problem and accept a final answer. Your evidence is the model, the checks, and the explanation.
08
Retrieval and spaced review
Closed-notes prompts: draw the system boundary, state whether it is open or closed and steady or transient, write the first law for it, and name where heat, work, and mass cross.
TodayRedo the worked example from a blank page.
+1 daySolve Level 1 without notes.
+3 daysSolve Level 2 with changed numbers.
+7 daysConnect this module to another course.
+30 daysAdd a portfolio artifact.
09
Mapping and portfolio task
Course mapping
Thermodynamics is the energy-accounting layer beneath heat transfer, fluid mechanics, and energy systems: master the closed- and open-system energy balances here and cycle analysis later becomes substitution.
First-pass focus: definitions, model setup, units, and worked examples. Save edge cases for the second pass.
Portfolio task
Create a one-page energy-balance note for a real device (kettle, fridge, or small engine): sketch, assumptions, equations, result, reasonableness check, limitation, and recommendation.