Concept Taxonomy

The 269 concepts in concept-list.md are sorted into 15 categories. Each category has a 3-6 character TaxonomyID used in the TaxonomyID column of learning-graph.csv and as the group key in learning-graph.json.

The organizing principle is the book's primary goal: understand what is being measured and how those measurements affect the natural and man-made environments. So each of the seven measured quantities gets its own category, holding its history, its physics, its units, and its instruments together. The technology categories support those seven, and the impact category collects what the measurements are used for.

See taxonomy-distribution.md for the concept count in each category.

Categories

Measurement Foundations

TaxonomyID: FOUND Color: SteelBlue

The vocabulary of measurement itself, independent of what is being measured. Units and the SI system, prefixes and conversion, scientific notation and orders of magnitude, and the quality vocabulary that the rest of the book leans on: resolution, accuracy, precision, uncertainty, calibration, and reference standards. These concepts are prerequisites for nearly every measurement concept in the book.

Sensors And Transduction

TaxonomyID: SENSE Color: DarkSlateBlue

How a physical property becomes a number. Transduction, analog and digital signals, and analog-to-digital conversion, plus the specific physical effects the book's sensors rely on: the piezoresistive effect, capacitive sensing, the thermoelectric and photoelectric effects, semiconductors, silicon diodes, and MEMS. Ends at the BME280, the sensor students actually hold.

Atmospheric Science

TaxonomyID: ATMOS Color: DarkGreen

The physical system being measured. The atmosphere and air masses, weather versus climate, high and low pressure systems and fronts, the water cycle processes of evaporation and condensation and precipitation, and the daily and seasonal cycles that show up in every logged dataset. This category is what makes the seven measurements a connected story instead of seven unrelated numbers.

Temperature

TaxonomyID: TEMP Color: LimeGreen

What temperature physically is (the kinetic energy of atoms), the instrument lineage from the thermoscope through liquid-in-glass to the thermocouple, resistance thermometer, and thermistor, and the three scales — Fahrenheit, Celsius, and Kelvin — with their fixed points and conversions. Includes the Stevenson screen, because how a thermometer is exposed is part of the measurement.

Barometric Pressure

TaxonomyID: PRESS Color: Gold

Pressure as the weight of the air above, the Torricelli and Puy de Dome experiments that established it, the mercury and aneroid instruments, and the competing units — inches of mercury, millibars, hectopascals, pascals — that all describe one atmosphere. Extends to sea level pressure, pressure altitude, the altimeter, and pressure tendency as a forecasting signal.

Humidity And Dew Point

TaxonomyID: HUMID Color: DarkGoldenrod

Water vapor in the air and the three ways to describe it: absolute humidity, relative humidity, and dew point. Includes the vapor-pressure physics that explains why warm air holds more water, the hygrometer and psychrometer instruments, the capacitive thin-film sensor used in the BME280, and the derived comfort measures — apparent temperature and heat index.

Solar Radiation

TaxonomyID: SOLAR Color: Khaki

The energy arriving from the Sun and the instruments that catch it. The electromagnetic spectrum, irradiance and the solar constant, insolation as irradiance accumulated over time, the pyrheliometer and pyranometer and bolometer, the photovoltaic path from the photoelectric effect to the solar cell, and the derived UV index. Albedo and solar zenith angle connect it back to the ground.

Wind

TaxonomyID: WIND Color: Teal

Air in motion, driven by the pressure gradient. Speed and direction, the vane and the anemometer families, the Beaufort scale as a measurement standard that required no instrument, competing speed units, the distinction between gust and sustained wind, and the storm-rating scales — Saffir-Simpson and Enhanced Fujita — that turn wind speed into a hazard category.

Ground Motion And Seismology

TaxonomyID: SEIS Color: DodgerBlue

Earthquakes, faults, and seismic waves; the instrument line from the seismoscope through the seismograph to the modern seismometer, all resting on the same inertial-mass principle; MEMS accelerometers as the affordable modern version; and the crucial distinction between magnitude scales (Richter, moment magnitude) that describe the event and intensity scales (Mercalli) that describe the shaking at a place.

Location Elevation And Time

TaxonomyID: GEO Color: LightSkyBlue

Where and when a reading was taken. Coordinate systems, latitude and longitude, the longitude problem and the marine chronometer that solved it, the prime meridian, trilateration and how GPS actually works, GNSS constellations, the WGS 84 datum, and the timekeeping concepts — atomic clocks, UTC, time zones, and timestamps — that let two stations' records be compared.

Hardware And Interfacing

TaxonomyID: HW Color: Crimson

The physical build. The Raspberry Pi and single-board computers, GPIO pins and headers, the electrical basics of voltage, current, and ground, the wiring parts (jumper wires, breadboard, pull-up resistor), the buses that carry sensor data — I2C with its device addressing, SPI, and serial UART — plus electrostatic discharge and the SIM7600A cellular module.

Computing And Programming

TaxonomyID: SYS Color: MediumPurple

Everything above the hardware. What an operating system does, Ubuntu Server and Raspberry Pi OS, the command line, the file system and permissions, editors, packages, and running a program as a systemd service. Then Python itself: variables, data types, functions, loops, conditionals, libraries, exception handling, and script execution.

Data Logging And Analysis

TaxonomyID: DATA Color: Indigo

Turning readings into a dataset and a dataset into a finding. Sampling intervals, time series, CSV structure down to the header row, storage and rotation and backup, then the analysis layer: line charts, scatter plots, axis labeling, moving averages, trend, and correlation. Ends with the data quality concepts — outliers, missing data, sensor drift, and validation — that separate a real event from an instrument fault.

Field Deployment And Power

TaxonomyID: DEPLOY Color: DarkOrchid

Making the station survive outdoors and unattended. Siting and sensor exposure, weatherproof enclosures and IP ratings, the power budget and the battery, solar panel, and charge controller that satisfy it, duty cycling to stretch it, and the telemetry chain — cellular link, Wi-Fi, base station — including what happens when the link is intermittent.

Environmental And Societal Impact

TaxonomyID: IMPACT Color: Orange

What the measurements are for. Weather forecasting and severe weather warnings, agriculture and evapotranspiration, energy demand and solar generation, aviation safety, building codes, urban heat islands, air quality, wildfire risk, flood and tsunami warning, and the long climate record. Closes with citizen science, data sharing, and science communication — how a student's own data reaches other people.