Learners make a sundial. In this time instructional activity, students determine the time of the day by creating a sundial. They check the time on the sundial, hourly, for one week. Afterward, they explore what happened to the shadows in...

Article reports on the debut of the world's most accurate atomic clock. Includes a vocabulary list.

A good mathematical account of what happens to time as you approach c: the speed of light. Also provides a rather a fascinating video (fly through the Lattice) - don't miss it. Take some time and explore this site.

This site from the U.S. Navy provides a great description of the history and workings of cesium based atomic clocks. Very interesting.

Explore geologic time of the Earth and learn how radioactive decay helps to establish a timeline.