USDA HARDINESS ZONES
the 13 zones by average annual extreme minimum — each range in °F and °C, with the a and b half-zones
THE MOHS HARDNESS SCALE
ten reference minerals and five household probes: who scratches whom
THE MOMENT MAGNITUDE SCALE
what a single step hides: ×10 in recorded amplitude and roughly ×32 in released energy — drawn to true scale
THE PERIODIC TABLE
all 118 elements: symbol, atomic number and IUPAC atomic weight in every cell — blocks in colour, lanthanoids and actinoids offset below
BASIC PHYSICS FORMULAS
fifteen formulas · every letter explained beneath it
THE ELECTROMAGNETIC SPECTRUM
eighteen decades of frequency · and how much of it the eye sees
PLASTIC RESIN CODES
the seven codes on the bottom of an article per ASTM D7611: which resin each number names and what it means for sorting
RESISTOR COLOUR CODE
the bands, the tolerances and the preferred series of two standards
ROCK CLASSIFICATION
the three classes, 24 named rocks and the cycle that links them — after USGS and NPS
THE SAFFIR-SIMPSON SCALE
five categories of hurricane wind — and how much more damage each next one does
SPECTRAL LINES
five gases on one wavelength scale, from the violet edge to the red
SPEED THRESHOLDS
six thresholds where a different physics begins · every figure computed, not typed