Petrology and cycles and the use of thermodynamic data and experiments in order to better understand the origins of rocks. There are three branches of petrology, corresponding to the three types of rocks: igneous, metamorphic, and sedimentary, and another dealing with experimental techniques: Petrology Petrology (from the Greek πέτρος, "pétros", "rock" and λόγος, "lógos", "subject matter", see -logy) is the branch of geology that studies rocks and the conditions under which they form. Petrology has three subdivisions: igneous, metamorphic, and sedimentary petrology. Igneous and metamorphic petrology are commonly taught together because they both contain heavy use of chemistry, chemical methods, and
What Work Is terribly damaged conditions of American labor, whose circumstance has perhaps never been more wrecked.” After Levine was named Poet Laureate, "What Work Is" reached the top of Amazon.com's "Movers and Shakers" list. What Work Is What Work Is is a collection of poetry by Philip Levine. The collection has many themes that are representative of Levine's writing including physical labor, class identity, family relationships and personal loss. Its primary focus on work and the working class led to it being studied with emphasis on Marxist literary criticism. The focus on work is expressed in thematically different ways throughout the collection.