Notes
Reading material from teachers and learners: theory, worked examples and questions that make you think. Some notes are made with AI, and they always say so.
Pick a subject to see its topics174 notes
Wave MotionHigh School (11–12)
Waves and Sound: Quick Revision
Wave speed, interference and beats, standing waves on strings and in pipes, the resonance tube, and the Doppler effect. With the usual slips and questions to check yourself.
Molecular Orbitals and Hydrogen BondsHigh School (11–12)
Molecular Orbitals and Hydrogen Bonding: Quick Revision
A brief note on Molecular Orbitals and Hydrogen Bonding: bonding and antibonding orbitals, the two energy orders, bond order and magnetism, the ions of oxygen, and the hydrogen bond. With a worked example, practice, a program and questions to check yourself.
Complex NumbersHigh School (11–12)
The Argand Plane and Quadratic Equations: Quick Revision
A brief note on The Argand Plane and Quadratic Equations: the conjugate and the modulus, dividing, points on the Argand plane, quadratics with a negative discriminant and square roots of complex numbers. With practice, a program and questions to check yourself.
Human ReproductionHigh School (9–10)
Reproduction in Human Beings: Quick Revision
A brief note on Reproduction in Human Beings: puberty, the male and female reproductive systems, fertilisation, the placenta and menstruation, and reproductive health and the sex ratio. With a worked example, practice, a program and questions to check yourself.
Chemistry by ComputerHigh School (11–12)
The Periodic Table as Data: Quick Revision
A brief note on The Periodic Table as Data: the elements as a pandas table, selecting, sorting and filtering, computed columns, plots of the trends coloured by block, and groupby, corr and diff to find patterns and breaks. With a worked example, practice, a program and questions to check yourself.
Averages: Mean, Median and ModeMiddle Stage (6–8)
A Data Project from Question to Report
The Weather Project: the six steps of a data project, showing a month of weather, its centre, spread and chances, linked days, and an honest report with a limit. With a worked example, practice, a program and questions.
Relative MotionHigh School (11–12)
Relative Motion: Quick Revision
Relative velocity along a line, meeting and catching up, position-time graphs, and relative velocity in two dimensions with rain, rivers and wind. With the usual slips and questions to check yourself.
Shapes of Molecules and HybridisationHigh School (11–12)
Shapes of Molecules: Quick Revision
A brief note on Shapes of Molecules: VSEPR shapes with and without lone pairs, sigma and pi bonds, and hybridisation from sp to sp3d2. With a worked example, practice, a program and questions to check yourself.
Complex NumbersHigh School (11–12)
Complex Numbers and Their Algebra: Quick Revision
A brief note on Complex Numbers and Their Algebra: the number , the form and equality, adding, subtracting and multiplying, the inverse and division, and the powers of . With a worked example, practice, a program and questions to check yourself.
Reproduction in PlantsHigh School (9–10)
Reproduction in Simple Organisms and Plants: Quick Revision
A brief note on Reproduction in Simple Organisms and Plants: variation, fission, budding, regeneration, spores, vegetative propagation, the flower, pollination, fertilisation and seeds, with a worked example and questions.
Chemistry by ComputerHigh School (11–12)
Moles and Reactions by Computer: Quick Revision
A brief note on Moles and Reactions by Computer: reading formulas into counts with a dictionary and re, molar mass and percent composition, the limiting reagent as a function, yield and gas volumes, and solutions in code. With a worked example, practice, a program and questions to check yourself.
Probability and ChanceMiddle Stage (6–8)
Probability: Quick Revision
A brief note on Chance: probability by counting, the chance that something does not happen, relative frequency and the long run, two events together, at least one, and taking without putting back. With a worked example, practice, a program and questions.
Dual Nature of Radiation and MatterHigh School (11–12)
Modern Physics: Quick Revision
Photons and the photoelectric effect, the stopping potential and its graph, Bohr's levels of hydrogen and its spectral series, and the de Broglie wavelength of matter. With the usual slips and questions to check yourself.
Lewis Structures and Ionic BondsHigh School (11–12)
Ionic and Covalent Bonds: Quick Revision
A brief note on Ionic and Covalent Bonds: Lewis structures and formal charge, the exceptions to the octet rule, lattice enthalpy and the Born-Haber cycle, bond parameters, resonance and dipole moment. With a worked example, practice and a program.
Sequences and SeriesHigh School (9–10)
The Sum of an Arithmetic Progression: Quick Revision
A brief note on The Sum of an Arithmetic Progression: the two forms of the sum formula, the sum of the first n natural numbers, working back from a sum, and the nth term from the sum. With a worked example, practice, a program and questions to check yourself.
Plant Life Cycles and Alternation of GenerationsHigh School (11–12)
Gymnosperms, Angiosperms and Plant Life Cycles: Quick Revision
A brief note on Gymnosperms, Angiosperms and Plant Life Cycles: naked seeds, cones and the reduced gametophytes, flowers, the embryo sac, double fertilisation, and the three patterns of life cycle. With a worked example, practice, a program and questions to check yourself.
Simulation and RandomnessHigh School (11–12)
Simulation and Data with pandas: Quick Revision
A brief note on Simulation and Data with pandas: seeded random numbers, Monte Carlo and its error, random walks and decay, the standard error, and pandas tables: selecting, cleaning, grouping and plotting. With a worked example, practice, a program and questions to check yourself.
Spread of DataMiddle Stage (6–8)
Range, IQR and Standard Deviation: Quick Revision
A brief note on Spread: the range, quartiles and the IQR, box plots, the variance and the standard deviation, which measure to use, and what adding or multiplying does to the spread. With a worked example, practice, a program and questions.
Current ElectricityHigh School (11–12)
Electric Circuits: Quick Revision
Ohm's law, resistors in series and in parallel, Kirchhoff's rules, cells with internal resistance, the most power a battery can give, and the Wheatstone bridge. With the usual slips and questions to check yourself.
Periodic TrendsHigh School (11–12)
Periodic Trends in Properties: Quick Revision
A brief note on Periodic Trends in Properties: radii and isoelectronic ions, ionisation and electron gain enthalpy, electronegativity, valence and the nature of oxides. With a worked example, practice, a program and questions to check yourself.
Sequences and SeriesHigh School (9–10)
Patterns and the nth Term: Quick Revision
A brief note on Patterns and the nth Term: what makes an AP, the common difference, the nth term, the nth term from the end, and problems with two given terms, three numbers in an AP and counting. With a worked example, practice, a program and questions to check yourself.
Bryophytes and PteridophytesHigh School (11–12)
Bryophytes and Pteridophytes: Quick Revision
A brief note on Bryophytes and Pteridophytes: liverworts and mosses, their gametophytes and dependent sporophytes, the first vascular plants, the prothallus, the four classes, and heterospory as a step towards seeds. With a worked example, practice, a program and questions to check yourself.
Solving EquationsHigh School (11–12)
Solving Equations and Calculus by Computer: Quick Revision
A brief note on Solving Equations and Calculus by Computer: bisection, Newton's method and brentq, polynomials and fits, systems of equations, slopes and areas from numbers, quad, and Euler's method with solve_ivp. With a worked example, practice, a program and questions to check yourself.
Data and SamplingMiddle Stage (6–8)
Data Tables, Kinds of Data and Fair Samples
A brief note on What Is Data?: tables of cases and variables, the four kinds of data, and how to choose a fair sample and ask a fair question. With a worked example, practice, a program and questions.
Electromagnetic InductionHigh School (9–10)
Electromagnetic Induction and Household Circuits: Quick Revision
Electromagnetic induction and Fleming's right-hand rule, the AC and DC generator, frequency and the mains, and safe house wiring with fuses and the earth wire. With the usual slips and questions to check yourself.