How did the sundials help people to tell time before their were clocks?

Sundials helped people tell time by using the position of the sun's shadow cast by a gnomon (a vertical stick or object) on a flat surface marked with hour lines. As the sun moved across the sky throughout the day, the shadow would shift, indicating the time based on its position relative to the hour lines. This method allowed individuals to approximate the time during daylight hours, providing a simple yet effective way to organize daily activities before the invention of mechanical clocks.