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 topics279 notes
Alternating CurrentHigh School (11–12)
Transformers and LC Oscillations: Quick Revision
A brief note on Transformers and LC Oscillations. The turns ratio and losses of a transformer. Why power is sent at a high voltage. The frequency and energy of an LC circuit. A worked example and questions to check yourself.
Bonding: Valence Bond and Crystal Field TheoryHigh School (11–12)
Bonding in Coordination Compounds: Quick Revision
A brief note on Bonding in Coordination Compounds: hybridisation, spin-only moments, crystal field splitting, CFSE, colour and stability. With a worked example, practice, a program and questions to check yourself.
CirclesHigh School (9–10)
Tangents to a Circle: Quick Revision
A brief note on Tangents to a Circle: the tangent and the radius, the two equal tangents from an outside point, and the circle inside a triangle or a four-sided figure. With a worked example, practice, a program and questions to check yourself.
Anatomy of Flowering PlantsHigh School (11–12)
Secondary Growth: Quick Revision
A brief note on Secondary Growth: how the vascular cambium and the cork cambium make a dicot stem thicker, annual rings, heartwood and sapwood, and the bark and lenticels, with a worked example and questions.
Trigonometry and Waves by ComputerHigh School (11–12)
Waves by Computer: Adding and Fitting: Quick Revision
A brief note on Waves by Computer: the travelling wave in numpy, adding waves for beats and standing waves, harmonics of a string, the FFT, sampling and aliasing, and fitting a sine with curve_fit. With practice, a program and questions.
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.
Alternating CurrentHigh School (11–12)
Series LCR Circuits and Resonance: Quick Revision
A brief note on Series LCR Circuits and Resonance: impedance and phase of a series circuit, resonance, the quality factor and the bandwidth, and average power with the power factor, with a worked example and questions to check yourself.
Isomerism in Coordination CompoundsHigh School (11–12)
Isomerism in Coordination Compounds: Quick Revision
A brief note on Isomerism in Coordination Compounds: structural isomers, cis and trans, fac and mer, optical isomers and how to count them. With a worked example, practice, a program and questions to check yourself.
CirclesHigh School (9–10)
Cyclic Quadrilaterals: Quick Revision
A brief note on Cyclic Quadrilaterals: the opposite-angle theorem, the exterior angle, the converse, cyclic trapezia and other shapes, and ways to show that four points lie on a circle. With a worked example, practice, a program and questions to check yourself.
Anatomy of Flowering PlantsHigh School (11–12)
Tissue Systems and the Anatomy of Root, Stem and Leaf: Quick Revision
A brief note on Tissue Systems and the Anatomy of Root, Stem and Leaf: the three tissue systems, and how to read a dicot and a monocot root, stem and leaf in section. With a worked example, practice, a program and questions to check yourself.
Trigonometry and Waves by ComputerHigh School (11–12)
Angles, the Unit Circle and Trigonometric Graphs: Quick Revision
A brief note on Angles, the Unit Circle and Trigonometric Graphs: degrees and radians, the unit circle, the graphs of sine, cosine and tangent, and checking identities with numpy. With a worked example, practice, a program and questions.
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.
Alternating CurrentHigh School (11–12)
AC Voltage and Simple AC Circuits: Quick Revision
A brief note on AC Voltage and Simple AC Circuits: peak and rms values, a resistor, a coil and a capacitor on an AC source, reactance, phasors and phase, with a worked example, practice and questions to check yourself.
Werner's Theory, Ligands and NomenclatureHigh School (11–12)
Werner's Theory and Naming Complexes: Quick Revision
A brief note on Werner's theory and naming complexes: the two valences, ligands and the coordination number, the oxidation state of the metal and the IUPAC rules for names and formulae. With a worked example, practice, a program and questions to check yourself.
CirclesHigh School (9–10)
Chords, Arcs and the Angles They Make: Quick Revision
A brief note on Chords, Arcs and the Angles They Make: the parts of a circle, equal chords, the perpendicular from the centre, and the angle that an arc makes at the centre and at the rim. With a worked example, practice, a program and questions.
Anatomy of Flowering PlantsHigh School (11–12)
Meristematic and Permanent Tissues of Plants: Quick Revision
A brief note on Meristematic and Permanent Tissues of Plants: the meristems and what each adds, the three simple tissues, xylem and phloem and their cells, with the usual slips, a worked example, practice, a program and questions to check yourself.
Biology by ComputerHigh School (11–12)
Genetics by Computer: Quick Revision
A brief note on Genetics by Computer: gametes as letters, sorted genotypes, Punnett squares with loops and Counter, two genes with itertools.product and the 9:3:3:1 ratio, the test cross, and simulated crosses with random.choice. With practice, a program and questions.
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.
Electromagnetic InductionHigh School (11–12)
Generators and Induction Problems: Quick Revision
A brief note on Generators and Induction Problems: the emf of a turning coil, rods and frames in fields, and the LR circuit, with a worked example, practice and questions to check yourself.
Lanthanoids and Actinoids (f-Block)High School (11–12)
The Lanthanoids and Actinoids: Quick Revision
A brief note on The Lanthanoids and Actinoids: the 4f and 5f rows, their oxidation states, the lanthanoid contraction and its effects, and uses. With a worked example, practice, a program and questions to check yourself.
Heights and DistancesHigh School (9–10)
Heights and Distances with Two Triangles: Quick Revision
A brief note on Heights and Distances with Two Triangles: two observation points, a tower on a building, moving objects and the width of a river. With a worked example, practice, a program and questions to check yourself.
Human Health and DiseaseHigh School (9–10)
Infectious Diseases and Immunity: Quick Revision
A brief note on Infectious Diseases and Immunity: infectious agents, how they spread, treatment, prevention, vaccines and HIV. With a worked example, practice, a program and questions to check yourself.
Biology by ComputerHigh School (11–12)
Growth and Populations by Computer: Quick Revision
A brief note on Growth and Populations by Computer: exponential growth, log axes, doubling time, logistic growth stepped in code, and fitting curves with polyfit and curve_fit. 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 (11–12)
Eddy Currents and Inductance: Quick Revision
A brief note on Eddy Currents and Inductance: why eddy currents brake and heat a conductor, self-inductance and its emf, mutual inductance, and the energy stored in a coil, with a worked example, practice and questions to check yourself.