SIAL floats over SIMA because the SIAL layer is significantly lighter than the SIMA layer.
According to geological descriptions, the most of the upper layer of the Earth is composed of the SIAL. Beneath this upper layer lies the SIMA, which makes up the lower portion of the Earth's composition.
The fundamental reason for this arrangement is density. As stated, "The SIAL is much lighter than the SIMA". This difference in density means the less dense SIAL material naturally rests above the denser SIMA material, causing the SIAL layer to float over the SIMA layer.
Here is a summary based on the provided information:
| Layer | Location | Relative Density/Weight | Key Characteristic |
|---|---|---|---|
| SIAL | Upper Portion | Much Lighter | Floats over SIMA |
| SIMA | Lower Portion | Heavier | SIAL floats above it |
This principle of less dense materials floating on top of denser materials is a key concept in understanding the Earth's layered structure.
