Thursday, April 7, 2011

Clock

History About Clock

A clock is an instrument used to indicate, keep, and co-ordinate time. The word clock is derived ultimately (via Dutch, Northern French, and Medieval Latin) from the Celtic words clagan and clocca meaning "bell". A silent instrument missing such a mechanism has traditionally been known as a timepiece.[1] In general usage today a "clock" refers to any device for measuring and displaying the time. Watches and other timepieces that can be carried on one's person are often distinguished from clocks.[2]
The Shepherd gate clock at the Royal Observatory, Greenwich
Replica of an ancient Chinese incense clock

The clock is one of the oldest human inventions, meeting the need to consistently measure intervals of time shorter than the natural units: the day; the lunar month; and the year. Devices operating on several different physical processes have been used over the millennia, culminating in the clocks of today.

Tuesday, April 5, 2011

Questions of time

5)A road widening project started on 23 July 2007. It is scheduled to be completed in 5 months 15 days. When will it be completed?

6)Find the duration from August 2004 to October 2008.

7)Find the duration from 19 June 2005 to 3 March 2008.