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 Is History? art. Though Carr conceded that historians cannot predict exact events in the future, he argued that historical generalizations can supply information useful to understanding both the present and the future. Carr argued that since scientists are not purely neutral observers, but have a reciprocal relationship with the objects under their study just like historians, that this supported identifying history with the sciences rather than the arts. Likewise, Carr contended that history like science has no moral judgements, which in his opinion supports the identification of history as a science. Carr was well known for his assertions in "What Is History?"