China's science sandglass timer is recorded as the earliest in the Western Han Dynasty, which is also an ancient instrument to measure time. It measures time in terms of how long it takes for quicksand to leak from one container to another. The most famous sand clock is the five-wheeled timer created by Zhan Xiyuan in 1360. The quicksand flows from the funnel-shaped sand pit to the sand bucket on the side of the gears, which drives the initial wheel and thus drives the mechanical gears to rotate. The last gear turns a central wheel that rotates on a horizontal plane, with a pointer on its axis that rotates on a lined instrument disc to show the time. This hour glasses with sand is quite amazing!