St. Peter's Square, Vatican City, Vatican, seen through the Balustrade atop the Basilica. Photo by Elisabetta Villa/Getty Images News/Getty Images. Definition: A balustrade is a row of repeating balusters-small posts that support the upper rail of a railing.Staircases and porches often have balustrades. balustrade is a row of repeating balusters-small posts that support the upper rail of a railing.
dissociation, in chemistry, separation of a substance into atoms or ions. Thermal dissociation occurs at high temperatures. For example, hydrogen molecules (H. The Columbia Electronic Encyclopedia, 6th ed. Copyright Â© 2012, Columbia University Press. All rights reserved.
One example of chemical and physical changes that appear almost identical, both in the initial processes and their reversal, is the dissolution of salt and sugar in water. Dissolving salt is a chemical change, while dissolving sugar is a physical change due to the nature of salt versus sugar.