Today, the sand clock for its direct purpose is used quite rarely, mainly they are used as a decorative element in decorating the interiors of the house, cabinet and other rooms. Sanding clock differ in size and time interval, which they measure, as a rule, sand clock can measure the time from several minutes to several hours.
The design of the sand clock at first glance seems very simple, these are two glass or plastic flasks that are interconnected. From the upper flask, the sand flows down with a thin stream and thereby measures a certain period of time. The accuracy of such hours from the quantity and quality of sand, from the volume of the flasks and from the width of the neck of the watch (holes between two flasks). Even in ancient times, in addition to sand, eggshell and marble sand could be used in such watches, and the size of the neck was determined by multiple experiments. So it was determined that the most accurate result is given by watches, which has a size of at least 1/12 of the diameter of the flask.
Starting from the 15th century, sand clock began to be used on ships, in churches and in the kitchen. There was even a special person on the sea vessels who controlled the state of the hourglass and turned them over on time, to know the exact time was his duty, this depended on the conduct of the ship’s magazine and the process of navigation of the vessel. At that time, there were hours that measured the intervals of time at 1 hour, 45, 30 and 15 minutes.
Today, in addition to decorative function, sand clock can be used for its intended purpose. They are used in the kitchen to count the time necessary for the preparation of any dish, in board games. The Australian Parliament uses a sand clock to measure time at its meetings.