  |
Smithsonian Institute - On Time - http://americanhistory.si.edu/ontime/
History of the clock and how Americans have measured time and been affected by it. |
| |
Cesium Atomic Clocks - http://tycho.usno.navy.mil/cesium.html
Kinds of cesium clocks, with pictures, plus a description of their operation and the science behind them. |
| |
How Stuff Works: Pendulum Clock - http://www.howstuffworks.com/clock.htm
Concise description using drawings and animation to show the operation of a pendulum clock. |
| |
How Stuff Works: Atomic Clock - http://www.howstuffworks.com/atomic-clock.htm
Concise history, background, definitions and operational information regarding atomic clocks. |
| |
Biological Clocks Virtual Museum - http://www.hhmi.org/biointeractive/clocks/museum.html
This exhibit explores the inputs, outputs, and mechanisms of biological clocks with a primary focus on circadian rhythms. |