How it is checked

Rules

• Every unit is stored once, as an exact fraction of its SI unit wherever the unit is defined exactly, with the source of that definition.
• Values are compared with reference values typed in separately from the NIST tables; the build stops on any mismatch.
• Every area and volume formula is compared with a Monte Carlo measurement of the shape, made from a point-in-shape test written from the shape’s definition, not from its formula. Selected perimeters and surfaces are integrated numerically.
• The formula shown on a page is the same expression that was checked; the page evaluates it live.
• Old values are not deleted. They are shown as “then and now”, so old documents can still be read.
• All text is new. The topics follow mid-century practical handbooks; no text or drawings are taken from them.

This build

units: 144, of which 141 exact
shapes: 42 (20 plane, 22 solid); every area/volume formula checked
signal: 40 flags and pennants, 49 Morse signs; weather: Beaufort 0-12, WMO codes 3700 and 4677
number: 59 symbols, 24 Greek letters, triangle solver, slide rule; sky: Sun, sidereal time, planets, 88 constellations, Vincenty
ship: 25 named parts, stability from the section polygon, IMO 2008 criteria, load-line marks; life: 15 IUPAC letters, 5 bases, A/B/Z forms, Lk = Tw + Wr
light: exact ray tracing (Snell, Fresnel, total internal reflection) through 5 materials from published dispersion formulas; lenses, prisms, mirrors, rainbow
units: 144, checked against references: 61, FAILURES: 0
FAILURES: 0
wave 2 checks: 40 flags, 49 Morse signs, Beaufort 0-12, 0 failures
wave 3 checks: 59 symbols, 24 Greek letters, 88 constellations; JS: Sun, sidereal time, planets, 88 constellations, Vincenty, trig, logs; 0 failures
wave 4: 258 checks passed (wave 4 JS: 202 checks passed)
wave 5: 10 checks passed (wave 5 JS: 123 checks passed)

Review

Pages are reviewed through the lenses of the studio charter: mathematics (formulas, topology), physics and metrology (units and constants), history (then-and-now notes), teaching (one clear point per page) and design (honest scales, accessibility). These reviews are done by the author applying those lenses. An outside review by working practitioners has not happened yet; if you find an error, it will be corrected and the correction noted.

Sources

• The International System of Units (SI), 9th edition (2019), with later updates, Bureau International des Poids et Mesures (BIPM).
• Resolution 3 of the 27th General Conference on Weights and Measures (2022): ronna, quetta, ronto, quecto, CGPM / BIPM.
• Guide for the Use of the International System of Units (SP 811, 2008), Appendix B: conversion factors, National Institute of Standards and Technology (NIST).
• Handbook 44, Appendix C: General Tables of Units of Measurement, National Institute of Standards and Technology (NIST).
• Refinement of values for the yard and the pound (international yard and pound agreement, 1959), US National Bureau of Standards, Federal Register 24 FR 5348; same values adopted by the UK, Canada, Australia, New Zealand and South Africa.
• Weights and Measures Act 1985, Schedule 1 (imperial units defined in metric terms), UK Parliament.
• The US survey foot (deprecated from 1 January 2023), NIST and the National Geodetic Survey.
• Resolution B2 (2012): re-definition of the astronomical unit of length, International Astronomical Union.
• World Geodetic System 1984 (WGS 84): equatorial radius a = 6 378 137 m, US National Geospatial-Intelligence Agency; parameters as registered in the EPSG Geodetic Parameter Dataset (IOGP).
• International nautical mile of 1852 m (International Hydrographic Conference, Monaco, 1929); listed among non-SI units in the SI Brochure, International Hydrographic Organization / BIPM.
• Kelvin defined through the Boltzmann constant (2019); degree Celsius t/°C = T/K − 273.15, BIPM (SI Brochure, section 2.3.1 and Table 4).
• International Code of Signals, 1969 edition revised 2005 (US edition: NGA Pub. 102, 2020), International Maritime Organization.
• Recommendation ITU-R M.1677-1: International Morse code, International Telecommunication Union.
• Radio Regulations, Appendix 14: phonetic alphabet and figure code, International Telecommunication Union.
• Convention on the International Regulations for Preventing Collisions at Sea, 1972, Part D (Rules 32 to 37), International Maritime Organization.
• Manual on Codes, Volume I.1 (WMO-No. 306): code table 3700 (state of the sea) and 4677 (present weather), World Meteorological Organization.
• Beaufort wind force scale, with probable wave heights, Met Office (UK national weather service).
• Coast and sea glossary: visibility terms used in shipping forecasts, Met Office (UK national weather service).
• Saffir-Simpson Hurricane Wind Scale, US National Hurricane Center (NOAA).
• Tropical cyclone FAQ: basins, names and seasons, NOAA Atlantic Oceanographic and Meteorological Laboratory, Hurricane Research Division.
• Natural Earth 1:110m land (public domain), via world-atlas 2.0.2, Natural Earth.
• Allied military phonetic spelling alphabets (secondary source; no primary text found online), Wikipedia.
• NOAA Global Monitoring Laboratory Solar Calculator: equations of the Sun’s position and the equation of time (after Meeus), US National Oceanic and Atmospheric Administration.
• Computing Greenwich Apparent Sidereal Time (from USNO Circular 179, 2005), US Naval Observatory, Astronomical Applications Department.
• Approximate Positions of the Planets: Keplerian elements and rates, Table 1 (1800–2050), E. M. Standish, NASA Jet Propulsion Laboratory, Solar System Dynamics.
• Planetary Fact Sheet, metric (updated 18 March 2025), NASA Space Science Data Coordinated Archive.
• Identification of a constellation from a position, PASP 99, 695 (1987); boundaries of Delporte (1930) at equinox 1875, N. G. Roman; catalogue VI/42 at the Strasbourg astronomical Data Center (CDS).
• The IAU Style Manual (1989), sections 5.15, 5.223 and 5.25, G. A. Wilkins for the International Astronomical Union.
• Resolutions B5 and B6 (2006): definition of a planet; Pluto, International Astronomical Union.
• The constellations: the 88 names and abbreviations adopted in 1922 and the boundaries of 1930, International Astronomical Union.
• Direct and inverse solutions of geodesics on the ellipsoid with application of nested equations, Survey Review 23 (176), 1975, T. Vincenty.
• Resolution 4 of the 27th CGPM (2022): on the use and future development of UTC (leap seconds to end by 2035), CGPM / BIPM.
• The Unicode Standard: code charts and character names (Mathematical Operators, Greek, Miscellaneous Symbols), The Unicode Consortium.
• ISO 80000-2:2019, Quantities and units, Part 2: Mathematics, International Organization for Standardization.
• A History of Mathematical Notations, 2 vols (1928–1929), Florian Cajori; public domain scan at the Internet Archive.
• International Convention on Load Lines, 1966, Annex I: regulations 4 to 8 (marks) and 40 (minimum freeboards); article 12 (fresh water), International Maritime Organization (IMO).
• International Code on Intact Stability, 2008 (2008 IS Code), resolution MSC.267(85), Part A, 2.2: criteria regarding righting lever curve properties, International Maritime Organization (IMO).
• Nomenclature for incompletely specified bases in nucleic acid sequences: recommendations 1984, Nucleic Acids Research 13 (1985) 3021–3030, Nomenclature Committee of the International Union of Biochemistry (A. Cornish-Bowden).
• Molecular structure of nucleic acids: a structure for deoxyribose nucleic acid, Nature 171 (1953) 737–738, J. D. Watson and F. H. C. Crick.
• Optimised parameters for A-DNA and B-DNA, Biochemical and Biophysical Research Communications 47 (1972) 1504–1509, S. Arnott and D. W. L. Hukins.
• Molecular structure of a left-handed double helical DNA fragment at atomic resolution, Nature 282 (1979) 680–686, A. H.-J. Wang, G. J. Quigley, F. J. Kolpak, J. L. Crawford, J. H. van Boom, G. van der Marel and A. Rich.
• Helical repeat of DNA in solution, PNAS 76 (1979) 200–203: 10.4 ± 0.1 base pairs per turn, J. C. Wang.
• Principles of Nucleic Acid Structure (Springer, 1984), the standard reference for helix dimensions, W. Saenger.
• The twisted circular form of polyoma viral DNA, PNAS 53 (1965) 1104–1111: the discovery of supercoiling, J. Vinograd, J. Lebowitz, R. Radloff, R. Watson and P. Laipis.
• DNA gyrase: an enzyme that introduces superhelical turns into DNA, PNAS 73 (1976) 3872–3876, M. Gellert, K. Mizuuchi, M. H. O’Dea and H. A. Nash.
• Self-linking and the Gauss integral in higher dimensions, American Journal of Mathematics 91 (1969) 693–728: Lk = Tw + Wr, J. H. White.
• The writhing number of a space curve, PNAS 68 (1971) 815–819, F. B. Fuller.
• Computation of writhe in modeling of supercoiled DNA, Biopolymers 54 (2000) 307–317: the exact formula for straight segments used here, K. Klenin and J. Langowski.
• Gazetteer of Planetary Nomenclature: IAU rules and naming themes for planets, satellites and their features, IAU Working Group for Planetary System Nomenclature, maintained by the USGS.
• Jovian moon-naming contest: the convention that Jupiter’s moons are named for descendants or consorts of Zeus (Jupiter), Carnegie Science, with names approved by the IAU.
• Oxford English Dictionary: etymologies of the days of the week and the months, Oxford University Press.
• Diccionario de la lengua española, nautical senses, Real Academia Española.
• Trésor de la langue française informatisé, nautical senses, Centre National de Ressources Textuelles et Lexicales (CNRS).
• Periodic Table: history and origin of each element’s name, Royal Society of Chemistry.
• Optical glass data sheets for N-BK7 and N-F2: Sellmeier coefficients, n_d, Abbe number (index relative to air), SCHOTT AG.
• Interspecimen comparison of the refractive index of fused silica, J. Opt. Soc. Am. 55, 1205-1209, I. H. Malitson (National Bureau of Standards).
• Measurement of the refractive index of distilled water from the near-infrared region to the ultraviolet region, Applied Optics 46, 3811-3820 (20 °C formula), M. Daimon and A. Masumura.
• Release on the Refractive Index of Ordinary Water Substance as a Function of Wavelength, Temperature and Pressure, International Association for the Properties of Water and Steam.
• Dispersion of air, J. Opt. Soc. Am. 62, 958-962, E. R. Peck and K. Reeder.
• Über Brechungsindizes und Absorptionskonstanten des Diamanten zwischen 644 und 226 mμ, Zeitschrift für Physik 15, 358-368, F. Peter.
• Les Météores, Discours huitième: de l’arc-en-ciel (published with the Discours de la méthode), René Descartes.
• Opticks: or, a Treatise of the Reflexions, Refractions, Inflexions and Colours of Light (1704; this text is the 4th edition, 1730), Book I, Isaac Newton.