Hourglass with divided sand

The hourglass is composed of two teardrop-shaped glass bulbs connected by a narrow central channel. The upper bulb contains light blue granular material, while the lower bulb holds a darker brown granular material. Two circular openings, one at the apex of each bulb, suggest points of entry and exit for the granular material. The hourglass exhibits radial symmetry around its vertical axis. A small white circular element is centered on the apex of the upper bulb. The object's function is to measure the passage of time as the granular material flows from the upper bulb to the lower.