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 topics435 notes
Transistors and Logic GatesHigh School (11–12)
Transistors and Logic Gates: Quick Revision
A brief note on Transistors and Logic Gates: the junction transistor and its characteristics, the amplifier and the switch, and the logic gates with their truth tables, with a worked example, practice and questions to check yourself.
States of MatterHigh School (11–12)
Vapour Pressure, Surface Tension and Viscosity: Quick Revision
A brief note on Vapour Pressure, Surface Tension and Viscosity: boiling and the Clausius-Clapeyron equation, capillary rise and bubbles, Stokes' law and Poiseuille's law. With a worked example, practice, a program and questions to check yourself.
StatisticsHigh School (9–10)
Cumulative Frequency Curves: Quick Revision
A brief note on Cumulative Frequency Curves: the less than and more than curves, reading the median and the quartiles, and the standard problems with a missing frequency, with a worked example, a program and questions to check yourself.
Structural Organisation in AnimalsHigh School (11–12)
The Cockroach, with the Earthworm and the Frog: Quick Revision
A brief note on The Cockroach, with the Earthworm and the Frog: the body, the gut, the open blood system, the air tubes, the nerves and the life cycle of the cockroach, with the usual slips and questions to check yourself.
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.
Semiconductors and DiodesHigh School (11–12)
Rectifiers, Zener Diodes and Light Devices: Quick Revision
A brief note on Rectifiers, Zener Diodes and Light Devices: half-wave and full-wave rectifiers, the capacitor filter, the Zener regulator, the LED, the photodiode and the solar cell, with a worked example, practice and questions to check yourself.
States of MatterHigh School (11–12)
Kinetic Theory and Real Gases: Quick Revision
A brief note on Kinetic Theory and Real Gases: molecular speeds and the Maxwell distribution, the compressibility factor, the van der Waals equation and the critical constants. With a worked example, practice, a program and questions to check yourself.
StatisticsHigh School (9–10)
Mode and Median of Grouped Data: Quick Revision
A brief note on Mode and Median of Grouped Data: the modal class, the mode formula, cumulative frequency, the median formula and the rule of thumb that links the three averages, with the usual slips, a program and questions to check yourself.
Structural Organisation in AnimalsHigh School (11–12)
Muscular and Neural Tissue, Organs and Organ Systems: Quick Revision
A brief note on Muscular and Neural Tissue, Organs and Organ Systems: the three muscles, the neuron and the neuroglia, the levels of organisation and the organ systems, with the usual slips 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.
Semiconductors and DiodesHigh School (11–12)
Energy Bands, Doping and the p-n Junction: Quick Revision
A brief note on Energy Bands, Doping and the p-n Junction: bands and gaps, electrons and holes, n-type and p-type, the depletion layer, bias and the diode equation, with a worked example, practice and questions to check yourself.
States of MatterHigh School (11–12)
Intermolecular Forces and Gas Laws: Quick Revision
A brief note on Intermolecular Forces and Gas Laws: the four forces and the three states, Boyle, Charles and Avogadro, the ideal gas equation and its units, Dalton and Graham. With a worked example, practice, a program and questions to check yourself.
StatisticsHigh School (9–10)
The Mean of Grouped Data: Quick Revision
A brief note on The Mean of Grouped Data: class marks, the direct method, the assumed mean method and the step deviation method, with the usual slips, a worked example, a program and questions to check yourself.
Structural Organisation in AnimalsHigh School (11–12)
Epithelial and Connective Tissues: Quick Revision
A brief note on Epithelial and Connective Tissues: the kinds of epithelium, the cell junctions, the glands, and the loose, dense and special connective tissues, with the usual slips 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.
Nuclei and RadioactivityHigh School (11–12)
Nuclear Reactions, Fission and Fusion: Quick Revision
A brief note on Nuclear Reactions, Fission and Fusion: the Q value and the threshold, the chain reaction and the reactor, and fusion in the Sun and on Earth, with a worked example and questions to check yourself.
Groups 17 and 18: Halogens and Noble GasesHigh School (11–12)
Halogens and Noble Gases: Quick Revision
A brief note on the halogens and the noble gases: trends in group 17, chlorine, hydrogen chloride, interhalogen compounds, the oxoacids of chlorine, and the noble gases with the fluorides and oxides of xenon. With a worked example, practice, a program and questions to check yourself.
Surface Areas and VolumesHigh School (9–10)
The Frustum of a Cone: Quick Revision
A brief note on The Frustum of a Cone: its slant height, the complete cone and similar triangles, the curved and total surface area, the volume, and a cone cut parallel to its base. With a worked example, practice, a program and questions to check yourself.
Biodiversity and ConservationHigh School (11–12)
Conserving Biodiversity: Quick Revision
A brief note on Conserving Biodiversity: in situ and ex situ methods, hotspots, protected areas, sacred groves, the Red Data Book and its categories, and the international efforts, with the usual slips 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.
Nuclei and RadioactivityHigh School (11–12)
Radioactive Decay and Half-Life: Quick Revision
A brief note on Radioactive Decay and Half-Life: alpha, beta and gamma decay, the law of decay with half-life and mean life, and activity, decay series and dating, with a worked example and questions to check yourself.