Sharp Rubber Duck

Rhombic Dodecahedrons

July 9, 2006

Soccer Balls and other round objects, here's a story you can take with a grain of salt – a round grain, as a matter of fact.

Because of the way atoms of sodium and chloride tend to combine, the result – table salt – tends to be cubic in shape. All of those microscopic flat surfaces make it easy for cubic salt granules to stick together, especially if there's any moisture in the air.

“I am sure everyone has experienced the annoyance with table salt which does not come out of the salt shaker,” Pushpito K. Ghosh, a researcher at the Central Salt and Marine Chemicals Research Institute in Bhavnagar, India, told The New York Times.

One solution to lumpy salt is, well, a solution. Fifty years ago, scientists discovered that adding the amino acid glycine to a salty brine solution slowed the growth around the 12 edges of a cubic crystal. Instead, salt crystals formed 12-sided, but almost spherical shapes, called rhombic dodecahedrons.

Round salt flows more easily from the shaker and is less likely to stick together. In a paper to be published in the journal Crystal Growth & Design, Ghosh and colleagues describe a possible process to commercially produce round salt. Other than its shape, however, the scientists are quick to report round salt tastes just like the cubic kind: salty.

Send this page to your friends..

Prior | Tell us what you think | Next

Add to Your Social Bookmarks: Del.icio.us Digg Furl Reddit Simpy Spurl Y! MyWeb - Netscape StumbleUpon