⏳ A sand clock, also known as an hourglass, is a timekeeping device that consists of two glass bulbs connected by a narrow neck. The upper bulb is filled with fine sand that flows through the neck into the lower bulb. As the sand gradually passes from one bulb to the other, it measures a specific amount of time. The sand clock has been used for centuries as a simple and reliable way to measure short periods of time. Its design represents the passage of time and serves as a visual reminder of the fleeting nature of moments.