2.2.2. Density

In accordance with the Newton’s laws of gravity the earth’s density has been calculated to be

5.5 (gms per cubic centimeter). However, it is surprising that the rocks near the surface of the earth have an average density of 2.7 only (gms per cubic centimeter). This density is less than half the average density of the earth as a whole. From this, it is clear that the density too increases with the increase in depth. The earth’s internal part is composed of very dense rocks; their density must be in the range of 8-10 (gms per cubic centimeter). The density of the central part of the core is still more.

Higher density could be due to heavy metals like Nichel and Iron at the centre as well as due to pressure of overlying layers.