time measurements

Simple text and photographs explain a year as a unit of time and Earth's orbit of the sun.

Simple text and photos explain a month as a unit of time and the months in a year.

Explores how humans have measured time throughout history, from moon calendars to sun clocks, hourglasses and other mechanical devices to electric, electronic, and atomic timepieces.

Introduces the various ways to determine time including calendars, clocks, stopwatch, and timer.

Photographs, illustrations, and simple text describes how humans have told time, from sundials to modern clocks.

Traces the history of measuring time, from the Stone Age to the twenty-first century.

Simple games and activities introduce the concepts of measuring weight, mass, and time.

Explains some of the different ways in which time is measured by clocks, calendars, days, hours, minutes, seconds, months, seasons, and the rituals of morning, noon, afternoon, evening, and night.

Examines the ways humans have measured time throughout history and discusses the various units that are used to keep track of it.

While traveling to an important feast in ancient China, Chuan and his friend Jing Jing devise a water "alarm" clock to make sure their party reaches the emperor's palace before rival warlords. Includes a brief history of water clocks and instructions for making one.