Keeping Time

The author Franklyn Branley was recommended to me recently for books on astronomy, and rather than look for a specific title, I decided to just see what our library had available by this author.  He was the chairman of the Hayden Planetarium at the height of the "space race", and wrote more than 140 books.  They clearly and intelligently describe such phenomena as thunderstorms, earthquakes, black holes, and what it's like to be an astronaut.  He mastered the trick of explaining things to kids without talking down to them.  

This book I found particularly cool.  In it, he explains dozens of concepts relating to time, including why our weeks have seven days, why we divide our days into 24 hours,  how time zones, daylight savings time, and the international dateline work,  how the Gregorian calendar works, and lots of mysterious things I can't recall ever wondering about until I found myself having to explain them to a skeptical child.  It can be tough to learn to tell time, especially if you can't count to 60 by fives.  And many of our time units have much more to do with ancient cultures than they do with rational mathematics.  A book that explains so many tough concepts so simply is a real treasure!