Question

what is the basic principle of a sundial

Answer 1

Sundials work from the shadow movement of a fixed object based on varying positions of the sun throughout the day. Imagine a stick placed vertically at the North Pole. As the Earth rotates on its axis, the shadow of the stick traces a full circle in a period of 24 hours.

Answer 2

Explanation:

Sundial, the earliest type of timekeeping device, which indicates the time of day by the position of the shadow of some object exposed to the sun's rays. ... As the day progresses, the sun moves across the sky, causing the shadow of the object to move and indicating the passage of time.