A hands-on family guide to the spring equinox: plant a stick, track its shadow, measure it at noon, and find true north with chalk and a child's height.

The equation of time explains why a sundial can run minutes fast or slow through the year, with simple dates and practical corrections for reading mean time.

A sundial shows local apparent solar time, while clocks show standard time. Longitude, daylight saving, and the equation of time explain the gap.