Oceanic crust is actually denser than continental crust.

Here's why:

* Composition: Oceanic crust is primarily composed of basalt and gabbro, which are rich in magnesium and iron. Continental crust is mainly made of granite and other less dense igneous rocks.

* Thickness: Oceanic crust is thinner (around 5-10 km) compared to continental crust (30-70 km).

* Age: Oceanic crust is younger and constantly being renewed through volcanic activity at mid-ocean ridges. This means it has had less time to cool and solidify, resulting in a higher density.

This density difference is important because it explains why oceanic crust subducts (sinks) beneath continental crust at convergent plate boundaries. The denser oceanic crust is forced down into the mantle, leading to volcanic activity and mountain formation.