On Time: From Seasons To Split Seconds

An award-winning science writer examines the ways humans have measured time throughout history and discusses the various units that are used to keep track of it. 40 color photos and color illustrations. Map included.

Award-winning science writer Gloria Skurzynski takes young readers on a fascinating tour through the history of time measurement. She shows how humans learned to recognize time and measure it in smaller and smaller units from Stonehenge, which marked the equinoxes; to Egyptian obelisks, which measured the hours; to modern-day atomic clocks, which split seconds into minuscule fractions.