Children will learn all about inventions: their inventors, the way they changed history, and their evolution over centuries, through the activities and anecdotes provided in this interactive series.From ancient civilization's earliest calendars and shadow clocks to the atomic clocks of today, the history of time measurement emerges in this interactive guide. The study of the evolution of timekeeping devices and the inventors of calendars and clocks is included and loaded with interesting facts and trivia. Fifteen hands-on activities help demonstrate humans' changing relationship with time over the centuries.