In a sand clock bottle, it takes a fraction of the time for sand from one sphere to flow through the pipe into the other, and people measure the time. The sand clock is much like the stopwatch we normally use. Once all the sand has drained into the bottom glass, it can be turned over to measure the time again. This is why the sandglass is different from ordinary timepieces. It is very convenient to use, especially when measuring short periods of time. It is a simple ancient people using simple tools to measure the time of a way to reflect the great creativity of human beings. Even today, the hour glass with sand has its uses, helping to time small activities.