Last revised 9/21/2026

Physics: Big Ideas

Secondary

Mental models for A-Level Physics, AP Physics 1 (Algebra-Based), and IB DP Physics.

This Gocademy collection teaches Physics through the ideas that make the subject coherent. It develops eight mental models — fields and forces, Newton's second law, conservation laws, momentum conservation, waves and superposition, electromagnetic fields, entropy and the second law, and quantum mechanics — and shows how they connect into a unified framework for approaching any problem in physics. Suitable for learners following A-Level Physics, AP Physics 1 Algebra-Based, or IB DP Physics. All examples, quizzes, and practice questions are original.

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2Modules11Sessions120Cards22Quizzes

Modules in this Collection’s System

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The Eight Big Ideas

How every force in physics arises from a field that eliminates action at a distance; how Newton's second law describes acceleration rather than the existence of motion; and how energy conservation constrains what outcomes are possible regardless of the details of the process.

8Sessions

Synthesis and Expert Thinking

How entropy determines the direction of spontaneous processes and sets fundamental limits on engines; how quantum mechanics is the correct theory of which classical mechanics is the large-scale limit; and how all eight ideas connect into a unified framework for approaching any problem in physics.

3Sessions

What You'll Walk Away With

8mental models connecting fields, Newton's laws, conservation laws, momentum conservation, wave superposition, electromagnetic fields, entropy, and quantum mechanics
1epistemological framework for understanding what physical theories are, how they are tested, and why a theory that is wrong can still be the right tool
1physical worldview — five habits of perception (scale, conservation, symmetry, order-of-magnitude, mathematical structure) applicable to any problem in physics
10synthesis claims reviewing the whole subject as a connected and coherent analytical framework

You'll Have Answers To

?Why can't we build a perfectly efficient heat engine, even in principle?
?How do we know electrons have wave properties if we can't see them?
?Why does light travel at the same speed regardless of the motion of the source?
?What actually happens to kinetic energy that is lost in an inelastic collision?
?Why do electrons in atoms not spiral into the nucleus as classical physics predicts?

Critical Concepts Explored

Field as Mediator of ForceAction at a Distance and Its ResolutionGravitational and Electric Field StrengthNewton's Second Law and Net ForceInertia and the Newtonian Mental ModelFree Body DiagramsNewton's Third Law PairsStatic and Dynamic EquilibriumConservation Laws as First QuestionsKinetic and Potential EnergyWork-Energy TheoremConservation of Mechanical EnergyElastic and Inelastic CollisionsConservation of MomentumImpulse and Change in MomentumSuperposition PrincipleConstructive and Destructive InterferenceStanding Waves and ResonanceDiffractionMaxwell's Equations and Electromagnetic WavesFaraday's Law and Electromagnetic InductionEntropy and the Second Law of ThermodynamicsCarnot EfficiencyArrow of TimeQuantum Mechanics as Correct FrameworkPlanck's Constant and QuantisationPhotoelectric EffectAtomic Energy Levels and Line SpectraWave-Particle DualityHeisenberg Uncertainty PrincipleDomain of Validity of Physical TheoriesPhysical Worldview and Scale Identification

Editor's Note

“A disciplinary physics guide that connects fields, Newton's laws, conservation laws, momentum, waves, electromagnetism, entropy, and quantum mechanics through eight durable mental models.”

This collection is useful because it does not reduce Physics to a catalogue of formulas and worked examples. It gives learners the mental models — field as force mediator, acceleration as what force causes, conservation laws as first questions, momentum conservation in isolated systems, superposition as wave principle, electromagnetic fields as physical entities, entropy as direction-setter, and quantum mechanics as the correct atomic framework — that explain why physical analysis takes the form it does.

Editor's Brief

Who it's for: Physics learners following A-Level Physics, AP Physics 1 Algebra-Based, or IB DP Physics who want the discipline to feel like a coherent set of analytical tools rather than a collection of formulas, definitions, and worked examples to be memorised.
What stands out: The collection builds from fields and forces through Newton's laws, conservation laws, momentum, wave superposition, electromagnetic fields, entropy, and quantum mechanics — showing at each step how the same analytical framework applies regardless of which topic is being studied, and concluding with the epistemological worldview that makes the whole framework coherent.
Read if: Read if you can recall physics formulas but struggle to know which one applies, find different physics topics feel unconnected, confuse force with motion or weight with mass, or want to understand what distinguishes expert physical thinking from competent equation matching.

Gold Quotes

Physics becomes coherent when you stop treating it as a collection of formulas to memorise and start recognising it as a set of questions about fields, forces, energy, and constraints — questions that the same analytical tools answer regardless of which topic you are studying.

The collection builds eight mental models that hold the discipline together — from fields and forces through Newton's laws, conservation laws, momentum, wave superposition, electromagnetic fields, entropy, and quantum mechanics — showing at each step how the same framework applies from a mechanics problem to a question about atomic spectra.

Every physical theory has a domain of validity, and using a theory outside its domain is not a simplification — it is the wrong model. Understanding where each theory fails is as important as knowing how to use it where it works.

Newtonian mechanics fails at high speeds and atomic scales. Special relativity fails when quantum effects matter. No theory is universally valid. The physicist's epistemological stance — checking domain before applying — is what distinguishes physical thinking from calculation.

Conservation laws are more powerful than force equations for most problems because they constrain the outcome without requiring knowledge of the interaction details — and identifying which conservation law applies is the first analytical move, not the last.

Conservation of energy and conservation of momentum bypass the internal forces of collisions, explosions, and field interactions entirely. The physical worldview starts by identifying what is conserved and ends by checking the answer in limiting cases — the middle steps are where force equations appear, only when conservation is insufficient alone.

About the Curator

GGocademy

Gocademy builds curriculum collections that turn subject demands into durable learning habits. The editorial voice is precise, conceptual, and focused on transfer rather than memorised procedures.