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hourglass

Also known as sandglass, sand timer, sand watch, sand clock, sandclock, sandwatch, sandtimer, sand glass

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)

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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Wikidata facts

Image: 3 Hourglasses Wellcome L0011331.jpg

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exact match: wordnet-rdf.princeton.edu/id/03549323-n
Unicode character: ⏳
Commons category: Hourglasses

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via Wikidata · CC0

~11 min read

Article

16 sections

Contents

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.