hourglass
Sign in to savethumb|upright|German half-hour sand glass, first quarter of the 16th century, bronze-gilt and silver-gilt, height: 8.3 cm, diameter: 8.4 cm, Metropolitan of Art (New York City)
AI overview
An hourglass is a timekeeping device consisting of two glass chambers connected by a narrow passage, with sand flowing from one chamber to the other to measure the passage of time. The example shown here is a German half-hour sand glass from the early 1500s, made of bronze-gilt and silver-gilt, demonstrating that hourglasses were valued enough to be crafted from precious materials for practical or decorative use.
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Article
16 sectionsContents
- History
- Antiquity
- Middle Ages
- Design
- Material
- Practical uses
- Modern practical uses
- Symbolic uses
- Modern symbolic uses
- Hourglass motif
- See also
- References
- Further reading
- Books
- Periodicals
- External links
thumb|upright|German half-hour sand glass, first quarter of the 16th century, bronze-gilt and silver-gilt, height: 8.3 cm, diameter: 8.4 cm, Metropolitan of Art (New York City)
An hourglass (or sandglass, sand timer, or sand clock) is a device used to measure the passage of time. It comprises two glass bulbs connected vertically by a narrow neck that allows a regulated flow of a substance (historically sand) from the upper bulb to the lower one due to gravity. Typically, the upper and lower bulbs are symmetric as they are usually manufactured by pinching a tube. The specific duration of time a given hourglass measures is determined by factors including the quantity and coarseness of the particulate matter and the neck width.