Question

State five characteristics of the earth’s crust. 

Answer 1

1. The crust is divided into two layers: sial and sima.
2. The sial lies on top of the sima.
3. Sial rocks are rich in silica and aluminium.
4. The sima is rich in silica and magnesium.
5. Average density of rocks is between 2.7 to 3.0 gm/cm3
6. The sial rocks are rigid and mainly granitic.
7. The sima rocks are solid in state.
8. Sima rocks are mainly basaltic and are elastic.