Core–mantle boundary Core–mantle boundary The core–mantle boundary (CMB in the parlance of solid earth geophysicists) of the Earth lies between the planet's silicate mantle and its liquid iron-nickel outer core. This boundary is located at approximately 2891 km (1796 mi) depth beneath the Earth's surface. The boundary is observed via the discontinuity in seismic wave velocities at that depth due to the differences between the acoustic impedances of the solid mantle and the molten outer core. P-wave velocities are much slower in the outer core than in the deep mantle while S-waves do not exist at all in the liquid portion of
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