Timekeeping: Explore the History and Science of Telling Time with 15 Projects

Gr 5–8—This title digs into the concept of timekeeping and shows not only the complexity, but also the malleable system that is just another creation of humankind. Readers will understand the reasons behind the International Date Line, prime meridian, daylight savings time, and other timekeeping systems. Written in a conversational tone with cartoon illustrations and clock-shaped "Did You Know?" fact boxes, it is an approachable and fascinating read that includes 15 projects ranging from simple to complex that, for the most part, can be completed with household materials. Kids can use a penny and a quarter to illustrate the difference between a solar and sidereal day, they can build a sandglass with a couple of plastic bottles, or discover how GPS works with three friends, a field, and a quarter. There are activities that will yield a number of amazing facts, such as the 300 different time zones that existed in the U.S. in the 1800s, and mind-blowing concepts, such as J. William Cupp's metric time system. Make time for this title.—Heather Acerro, Rochester Public Library, MN