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THE VISUAL LEARNING STUDIO
See the idea. Understand the connection.
35 visual explanations across 29 chapters, with topic maps throughout the library.
The chapter index will grow as additional notes are prepared. Chapters shown here are a learning collection, not a claim that the entire exam syllabus is complete.
SEE IT. CONNECT IT. EXPLAIN IT.
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Study the expanded notes and the credited detailed textbook lessons. The current chapter index covers core topics; it is not a claim of exhaustive coverage of every examination syllabus. Check the official syllabus and primary references.
Heat and Energy — lesson overview
Temperature, heat and internal energy
Temperature is a state variable related to thermal equilibrium. Heat is energy transferred because of a temperature difference, not a substance stored in a body.
Internal energy depends on the microscopic state of a system. A system can exchange energy through heat and work.
State variables describe a state; heat and work depend on the process, not merely its endpoints.
First law and sign convention
Using the convention that Q enters the system and W is work done by the system, ΔU = Q − W. Other sign conventions must be stated consistently.
An isothermal process has constant temperature. For an ideal gas, internal energy depends only on temperature, so its isothermal ΔU is zero.
An adiabatic process has no heat transfer, Q = 0; it is not necessarily isothermal. Work can still change internal energy.
Heat capacity and limitations
For a suitable temperature interval without phase change, Q = mcΔT relates heat transfer to mass and specific heat capacity under the relevant conditions.
During a phase change, energy can be transferred without a temperature increase; latent heat must then be considered.
The second law limits the complete conversion of heat from a single reservoir into cyclic work. A heat engine’s performance requires attention to reservoirs and losses.
