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.

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.

Questions of time

1)Find the duration from March 2008 to October 2008.

2)Find the duration from 1957 to2008.

3)Find the duration from 18 September 2007 to 5 December 2007.

4)A few groups of junior football teams were at a training camp from 14 October 2007 to 6 February 2008.How long were they at camp?

game about clock

A sundial is a device that measures time by the position of the Sun. In common designs such as the horizontal sundial, the sun casts a shadow from its style onto a surface marked with lines indicating the hours of the day. The style is the time-telling edge of the gnomon, often a thin rod or a sharp, straight edge. As the sun moves across the sky, the shadow-edge aligns with different hour-lines. All sundials must be aligned with the axis of the Earth's rotation to tell the correct time. In most designs, the style must point towards true celestial north (not the north magnetic pole or south magnetic pole). That is, the style's horizontal angle must equal the sundial's geographical latitude.
Unfortunately, it is common for inexpensive decorative sundials to have incorrect hour angles, and these cannot be adjusted to tell correct time.