METEOR SHOWERS
the twelve principal showers of the year · periods, peaks and ZHR per the IMO calendar
PHASES OF THE MOON
eight phases · a full cycle of 29.53 days
SPRING AND NEAP TIDES
the Earth–moon–sun geometry that makes the tides swing — after NOAA
BLOOD PRESSURE CATEGORIES
the six AHA categories · 2025 guideline · the higher of the two readings decides
CPR AND CHOKING
the 2025 American Heart Association algorithms, step by step — bystander, trained rescuer, and choking at three ages
DRESS CODES
six lines that turn up on an invitation, and what each one actually asks for — after Debrett’s
THE CHILD IMMUNIZATION SCHEDULE
Table 1 of the CDC schedule, by age: all twenty rows from birth to 18 years, United States, 2025
MAGNESIUM COMPOUNDS
the share of magnesium in the salt, computed from the formula · and what human trials measured
NAIL SHAPES
eight shapes at one scale · what tells them apart in millimetres
SERUM ACTIVES
when to apply, what to keep apart in time, what the season changes
THE STAGES OF SLEEP
light, deep and REM as honest shares of the night — and the 90–110 minute cycles it is built from
BITS, BYTES, KILOBYTES
two scales · 1000 and 1024 · why a drive looks smaller