Structure of the Earth the crust, upper mantle, lower mantle, outer core, and inner core. The geologic component layers of Earth are at the following depths below the surface: The layering of Earth has been inferred indirectly using the time of travel of refracted and reflected seismic waves created by earthquakes. The core does not allow shear waves to pass through it, while the speed of travel (seismic velocity) is different in other layers. The changes in seismic velocity between different layers causes refraction owing to Snell's law, like light bending as it passes through a prism. Likewise, reflections are caused by a large
Science of Education: Its General Principles Deduced from its Aim and the Aesthetic Revelation of the World Science of Education: Its General Principles Deduced from its Aim and the Aesthetic Revelation of the World Science of Education (full title: Science of Education: Its General Principles Deduced from its Aim and the Aesthetic Revelation of the World) is a book written by the German empiricist Johann Friedrich Herbart. It was first published in German in 1806 and the first English printing was in 1902. Herbart emphasized education as the way for an individual to fulfill his potential and created a scientific method to help him do so. The Science of Education advocated a five-step methodology that appeals to