ABSTRACT
The main areas of philosophy include metaphysics, which deals with the fundamental nature of reality and being; ethics, which deals with the study and reflection about morals; epistemology, which defines the basis of knowledge, its limits and validity. In the ancient classical era, philosophy was usually divided into three main branches: natural philosophy, metaphysical philosophy, and moral philosophy. The liberal arts, terminology organized in the middle ages to define the teaching methodology, included the trivium, with rhetoric, logic, and grammar, and the quadrivium, with music, arithmetic, geometry, and astronomy. Natural philosophy, which later became known as physics, included the study of the real world. It was divided in time into several natural sciences, encompassing astronomy, physics, chemistry, biology, and cosmology. Helmholtz resonance is a sound-producing phenomenon which occurs when the air goes through a cavity.
