Update Log

Audit trail of architectural evolutions, knowledge syntheses, and bundle restructuring.

2026-09-20

• MermaidViewer Component with Zoom & Pan: Implemented an interactive React component (src/components/MermaidViewer.tsx) and auto-hydrator (src/components/MermaidHydrator.tsx) for Mermaid diagrams. Features smooth zoom in/out controls with percentage badge, mouse-wheel zooming, drag-to-pan canvas, double-click reset, fullscreen modal view, and source code copying. Integrated into BrainLayout.astro for automatic hydration of all markdown Mermaid blocks.

• Mathematics Area: Created Cambridge IGCSE-aligned area note for Mathematics (areas/mathematics.md), establishing the four core syllabus domains (Number, Algebra & Graphs, Shape & Space, and Probability & Statistics) with a Mermaid curriculum branch flowchart, authoritative citation of Cambridge IGCSE Mathematics 0580 syllabus, and index integration in areas/index.md.

• Mass Concept & Diffusion Relationship: Added Cambridge IGCSE-aligned atomic concept note for Mass (concepts/mass.md), detailing the definition of mass as quantity of matter and inertia, kinetic particle theory basis for diffusion speed ($\overline{E_k} = \frac{1}{2}mv^2 \implies v \propto 1/\sqrt{m}$), the classic $\text{NH}_3$ vs. $\text{HCl}$ gas diffusion tube demonstration with ASCII diagram, and bidirectional cross-linking with Diffusion (concepts/diffusion.md) and Chemistry (areas/chemistry.md).

• Endothermic Change Concept: Added Cambridge IGCSE-aligned atomic concept note for Endothermic Change (concepts/endothermic-change.md), detailing thermal energy absorption ($\Delta H > 0$), reaction pathway and activation energy profile diagrams, chemical bond breaking/making balances (thermal decomposition, photosynthesis), latent heat absorption in melting and boiling/evaporation to overcome intermolecular forces, and cross-linking with Chemistry (areas/chemistry.md), Exothermic Change (concepts/exothermic-change.md), Melting (concepts/melting.md), and Boiling (concepts/boiling.md).

• Intermolecular Force & Exothermic Change Concepts: Added Cambridge IGCSE-aligned atomic concept notes for Intermolecular Force (concepts/intermolecular-force.md) and Exothermic Change (concepts/exothermic-change.md), detailing intramolecular vs. intermolecular forces, kinetic particle theory across physical states, activation energy and enthalpy profile diagrams ($\Delta H < 0$), chemical bond breaking/making balances, latent heat releases in freezing and condensation, and bidirectional cross-linking with Chemistry (areas/chemistry.md), Intermolecular Space (concepts/intermolecular-space.md), Freezing (concepts/freezing.md), and Condensation (concepts/condensation.md).

• Intermolecular Space Concept: Added Cambridge IGCSE-aligned atomic concept note for Intermolecular Space (concepts/intermolecular-space.md), detailing empty volume separation between particles, state-by-state comparisons (solids, liquids, gases), particle arrangements, compressibility consequences, ASCII state diagrams, and cross-linking with Particle (concepts/particle.md) and Kinetic Particle Theory (concepts/kinetic-particle-theory.md).

• Particle, Atom, Molecule & Kinetic Particle Theory Concepts: Added Cambridge IGCSE-aligned atomic concept notes for Particle (concepts/particle.md), Atom (concepts/atom.md), Molecule (concepts/molecule.md), and Kinetic Particle Theory (concepts/kinetic-particle-theory.md), detailing subatomic structure (protons, neutrons, electrons), covalent bonding in elements and compounds, particulate classification, particulate dynamics across states of matter, and comprehensive cross-linking with phase changes.

• Kinetic Particle Theory of Matter Resource: Added Cambridge IGCSE-aligned reference resource (resources/kinetic-particle-theory-of-matter.md) synthesizing foundational postulates of particulate matter, kinetic energy relationship ($\overline{E_k} \propto T$), state structures (solid, liquid, gas), phase transitions, and ASCII particle diagrams with cross-linking to Chemistry (areas/chemistry.md), State of Matter (concepts/state-of-matter.md), and gas volume dynamics.

• Effects of Temperature and Pressure on the Volume of Gas Resource: Added Cambridge IGCSE-aligned reference resource (resources/effects-of-temperature-and-pressure-on-the-volume-of-gas.md) detailing kinetic particle theory, Charles’s law ($V \propto T$), and Boyle’s law ($P_1 V_1 = P_2 V_2$) with piston compression/expansion diagrams and bidirectional cross-linking to Chemistry (areas/chemistry.md) and State of Matter (concepts/state-of-matter.md).

• Pure Substance & Lattice Concepts: Added Cambridge IGCSE-aligned atomic concept notes for Pure Substance (concepts/pure-substance.md) and Lattice (concepts/lattice.md), detailing criteria of purity (sharp melting/boiling points, paper chromatography), crystal structures (giant ionic, giant covalent, giant metallic, simple molecular), and comprehensive cross-linking with phase transitions and state of matter.

• Volatile & Volatility Concepts: Added Cambridge IGCSE-aligned atomic concept notes for Volatile (concepts/volatile.md) and Volatility (concepts/volatility.md) detailing the role of weak intermolecular forces in rapid surface evaporation, relationships to boiling points and vapor pressure, laboratory safety, and cross-linking with Evaporation (concepts/evaporation.md).

• Evaporation, Boiling & Condensation Concepts: Added Cambridge IGCSE-aligned atomic concept notes for Evaporation (concepts/evaporation.md), Boiling (concepts/boiling.md), and Condensation (concepts/condensation.md) detailing surface vs. bulk vaporization, evaporative cooling dynamics, specific latent heat of vaporization ($\Delta E = m \cdot l_v$), purity criteria, and kinetic particle theory mechanisms.

• Melting & Freezing Concepts: Added IGCSE-aligned atomic concept notes for Melting (concepts/melting.md) and Freezing (concepts/freezing.md) detailing kinetic particle theory, heating and cooling curve plateaus, specific latent heat of fusion ($\Delta E = m \cdot l_f$), and purity/freezing-point depression criteria.

• Saturn Planetary Case Study: Augmented State of Matter (concepts/state-of-matter.md) with an IGCSE-aligned planetary science case study illustrating gaseous atmospheres ($\text{H}_2, \text{He}$), liquid metallic hydrogen, solid ice rings, and bulk density anomalies relative to liquid water.

• State of Matter: Created concept note for State of Matter (concepts/state-of-matter.md) under the Chemistry area (areas/chemistry.md), establishing thermodynamic and kinetic models of phase behavior.

• Chemistry & Diffusion: Established the Chemistry area (areas/chemistry.md) and added foundational concept note for Diffusion (concepts/diffusion.md).

• Initialization: Initialized the Second Brain OKF v0.2 bundle structure with Astro Content Collections integration.

• Core Concepts: Added foundational concepts for Open Knowledge Format (concepts/open-knowledge-format.md) and Second Brain Methodology (concepts/second-brain-methodology.md).

• Active Projects: Documented the Astro Second Brain implementation project (projects/astro-second-brain.md).

• Resources: Synthesized Tiago Forte’s Building a Second Brain (resources/building-a-second-brain.md).