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? that historians deem unimportant, and "historical facts", information that the historians have decided is important. Carr contended that historians arbitrarily determine which of the "facts of the past" to turn into "historical facts" according to their own biases and agendas. For this reason, Carr argued that Leopold von Ranke's famous dictum "wie es eigentlich gewesen" (show what actually happened) was wrong because it presumed that the "facts" influenced what the historian wrote, rather than the historian choosing what "facts of the past" he or she intended to turn into "historical facts". At the same time, Carr argued that the study