Curated OER
Time
Learners make a sundial. In this time lesson, 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 reference to...
Society for Science and the Public
Science News for Students: World's Coolest 'Clock' Is Also Accurate
Article reports on the debut of the world's most accurate atomic clock. Includes a vocabulary list.
Fourmilab Switzerland
John Walker: C Ship: The Dilation of Time
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.
US Navy
U.s. Navy: Atomic Clocks
This site from the U.S. Navy provides a great description of the history and workings of cesium based atomic clocks. Very interesting.
American Geosciences Institute
American Geosciences Institute: Earth Science Week: Geologic Age
Explore geologic time of the Earth and learn how radioactive decay helps to establish a timeline.