A Clock is a device used to keep, measure and indicate time. Clocks are said to be one of the oldest inventions of the human being, meeting a dire need to measure intervals of time shorter than the natural units like the day or the lunar month or the period of the entire year. Devices working on various physical processes have been used over a very long time. Some of the predecessors of the modern clock were often based on the movement of nature and were also termed as clocks. The one which shows time by representing the shadow of the sun on a flat surface is called a sundial. In order to measure the duration time, instruments like hourglass have been used. There are also water clocks which are considered to be one of the oldest time measuring devices. The major advancement came into the manufacturing system of clocks after the invention of verge escapement, which made possible the production of the first mechanical clock in 1300s in Europe. It used to keep time with oscillating timekeepers like balance wheels.
In horology, traditionally the clocks which did not strike hourly with some sound were known to be a timepiece and the one which produce the strike sound was called a clock.
In this sub category you can download free PNG images: Clock Objects. In this category "Clock" we have 159 free PNG images with transparent background.