Question

1. why were shadows useful for measuring time in the past?

Explanation:

Shadows from a sun - cast object (like in a sundial) change predictably with the sun's movement. The sun’s apparent motion across the sky causes the shadow’s length and position to shift in a regular, time - related pattern. In the past, this predictable change allowed people to mark time intervals (e.g., hours) as the shadow moved, as the sun’s path was consistent daily and seasonally, making shadows a reliable natural time - measuring tool with simple setup (no complex technology needed).

Answer:

Shadows (e.g., in sundials) were useful for measuring time in the past because the sun's apparent motion across the sky causes a sun - cast object's shadow to change length/position in a predictable, time - related pattern. This regular shift let people mark time intervals, and the method was simple (no complex tech) with the sun's consistent daily/seasonal path ensuring reliability.