Explain the difference between what forms when 2 continental plates collide and
what forms when 2 oceanic plates collide?

The difference is what it  forms

2 continental plates: mountains

2 oceanic plates: island arcs (some may contain volcanoes)

Explanation:

- The continental crust buckles up and rocks pile up, creating mountains.

- Because two oceanic plates have equal densities, when they collide, the younger plate will force the older plate downwards (this is called subduction.) then the older plate being forced downwards will melt and the molten materials build up causing a lot of pressure upward, forcing its way to the surface. Once the molten materials meet with the water, it begins to cool forming island arcs.