Sundial

Ages

Introduction

Summary

The Earth moves around the sun but, in our terrestrial frame of reference, the sun seems to move around the Earth. This periodic motion is the basic principle underlying the sundial.  The shadow cast by the “gnomon” indicates the hour of the day.

Goals

• To illustrate a famous application dealing with the straight-line path of light.

Features

Click on  to go on step by step.

Tags

sun sundial sun shadow day night time gnomon