Interior of the Earth The study of Earth's interior structure has evolved from early theories like Sir Eduard Suess's three-layer model to modern understanding based on seismic wave analysis and other scientific methods. Sir Suess proposed an early model of Earth's interior divided into three distinct layers: - SIAL - SIMA - NIFE SIAL Layer → It is dominated by Silica and Aluminium . → Average density is 2.7 gm/cm³ . → Thickness is 30 to 50 km over continent & 0 to 5 km over ocean . → Continental crust is made up of SIAL and it is dominated by Granitic rocks . SIMA → Made up of denser material, having average density of 3.0 gm/cm³ . → Heavy minerals such as iron and magnesium . → It forms oceanic crust and has dominance of Basaltic rocks . NIFE → It is most dense layer which forms core. → Average density is 11 gm/cm³ . → Domina...