沙漏作为历史久远的计时工具一直被沿用至今，其蕴含的物理原理仍然应用在生活的各个方面. 本文研究了不同材质的颗粒物质在其直径极其细小、比表面积急剧增大的情况下，颗粒物对于同样直径的洞口流量随颗粒直径大小成正相关的特殊现象. 同时测量了最大稳定角，并进一步探究了开口直径、倾斜角度等因素对流速的影响，结合实验现象在颗粒物极其细小的条件下对Beverloo 公式的参数进行了修正.

The hourglass has been used as a historical time-keeping tool and its physical principles are still applied in all aspects of life. In this paper，different particle materials are studied. Under the condition that the diameter of particles is extremely small and the specific surface area is sharply increased，the flow rate of particles is positively correlated with their diameters when keeping the hole of the same diameter. At the same time，the maximum stability angle is measured and the influence of factors，such as opening diameter and inclination angle on the flow velocity is further explored.