Hourglass

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For other uses, see Hourglass (disambiguation).

Image:Wooden hourglass.jpg An hourglass, also known as a sandglass or sand timer, is a device for the measurement of time. It consists of two glass bulbs placed one above the other which are connected by a narrow tube. One of the bulbs is usually filled with fine sand which flows through the narrow tube into the bottom bulb at a given rate. Once all the sand has run to the bottom bulb, the device is inverted in order to measure another time period.

Factors affecting the amount of time that the hourglass measures include: the volume of sand, the size and angle of the bulbs, the width of the neck, and the type and quality of the sand. Alternatives to sand that have been used are powdered eggshell and powdered marble. It is still in use, but typically only ornamentally or when a relatively approximate measurement of time is needed (for example in cooking or board games). For cooking and games the time period will be only a few minutes (for cooking eggs, a three minute timer is typical, hence the nickname eggtimer for three minute hourglasses). Today, hourglass collecting has become a niche but avid hobby for some, with elaborate or antique hourglasses commanding huge prices.

Whilst they are no longer widely use for keeping time, some institutions do maintain them, the Australian parliament uses an hourglass to time certain procedures such as divisions.

1 History
2 Example use
3 Related terms
4 Appearances in modern works
5 See also

[edit] History

Although the Ancient Greeks, Romans and other cultures undoubtedly had the glassmaking technology to construct hourglasses, there is no concrete evidence of their existence in ancient times. Since the hourglass was one of the few reliable methods of measuring time at sea, it has been speculated that it was in use as far back as the 11th century, where it would have complemented the magnetic compass as an aid to navigation.

However, it is not until the 14th century that evidence of their existence was found, appearing in a painting by Ambrogio Lorenzetti 1328.

The hourglass was often depicted on pirate flags where it symbolised the fact that human existence is fleeting, and in England hourglasses were sometimes placed in coffins to symbolise the fact that the "sands of time" had run out. In literature, references to time measuring devices can represent death. There are images depicting the grim reaper holding an hourglass.

[edit] Example use

During the voyage of Ferdinand Magellan around the globe, his vessels kept 18 hourglasses per ship. It was the job of a ship's page to turn the hourglasses and thus provide the times for the ship's log. Noon was the reference time for navigation, which did not depend on the glass, as the sun would be at its zenith.

[edit] Related terms

(Slang) A woman with a narrow waist and full hips and bust is said to have an hourglass figure.

Hourglass Model - a project research approach (Trochim, W.M.K, 2005). The hourglass model starts with a broad spectrum for research, focusing in on the required information through the methodology of the project (like the neck of the hourglass), then expands the research in the form of discussion and results.

[edit] Appearances in modern works

In MGM's The Wizard of Oz, the Wicked Witch of the West had a huge menacing hourglass, with supports in the form of winged griffins. After turning the hourglass over, the Witch threatened Dorothy, "Do you see that?! That's how much longer you've got to be alive... and it isn't long my pretty, it isn't long!" The blood red sand began to fall, counting down the time to Dorothy's supposed demise.

In computer operating systems, an icon of an hourglass has often been used as a mouse pointer when the computer has exceeded its RAM or other system resources, it tells the user to wait a minute while the computer processes all outstanding tasks.

In Walt Disney's Aladdin, the evil wizard Jafar traps Princess Jasmine inside an enormous hourglass.

A relatively large hourglass is used by the character Imhotep (played by Arnold Vosloo) in The Mummy Returns while threatening the boy named Alex O'Connell.

Four giant hourglasses filled with various gems are found in J.K. Rowling's Harry Potter and they are used to record the house points of Hogwarts' four houses.

A tiny hourglass is the shape of Hermione Granger's Time Turner in Harry Potter and the Prisoner of Azkaban by J.K. Rowling (later also appeared in the movie with the same title). When spun, this device enables time travel.

In Ubisoft's Prince of Persia: The Sands of Time and its sequel Warrior Within the Hourglass is an object that is central to the plot.

In the Philippines, a Golden Hourglass was used for a tele-fantasya, Etheria, continuation of the Encantadia trilogy.

In Days of Our Lives, the hourglass is the symbolic icon shown in the beginning and end credits.

In the Area 88 remake, a rebel sniper uses the hourglass as a symbolism of when someone's life (The mercenary pilot/base personnel) was already over.

An hourglass will be featured in the upcoming Nintendo DS game, The Legend of Zelda: Phantom Hourglass.

In the video game Kula World, an hourglass is used as the timer to show players how much time is left on their current levels.

In the Discworld series, Death's Domain has the Room of Lifetimers, a room filled with the hourglass (lifetimer) of every living being in the world. The room even has a hidden, much smaller room (the size of a cathedral) adjoining it, which contains the lifetimers of the gods.

Some video games, when levels are timed, have power-ups in the shape of hourglasses. Typically, these add one minute to the clock immediately. An example of this is the original Jazz Jackrabbit game.

The Catacomb 3D series of computer games features an hourglass-based power-up that freezes all of the action (except for the hero, Petton) until a counter reaches zero (i.e., "100 grains of the Sands of Time," where each grain represents an unstated interval of time.)