Help children measure and tell time by the sun, the clock and the calendar; and learn why there are 24 hours in a day, 7 days in a week and 365 days in a year. Here's a cross-curriculum approach to time with learning activities that bring together history, science, language arts and math. A comprehensive look at time from the ancient civilizations who first tried to understand, arrange and measure it - to modern society where we organize our lives around the clock!Oravity-Frcc Mechanical Clocks In the 1730s an English clock maker named John Harrison built a clock that was entirely independent ... measurements until the 1930s, it was replaced in popularity by new clocks that ran with gears, tightly coiled springs and manual winding. ... could keep time to within 2/1000 of a second each yearl By the 1930s this discovery was put to use in digital clocks and watches.
|Title||:||It's About Time (eBook)|
|Author||:||Robynne Eagan, Tracey Ann Schofield|
|Publisher||:||Lorenz Educational Press - 1997-03-01|