As Earth was forming in its earliest history and probably when the collision that resulted in the formation of the Moon occurred more than 4 billion years ago, Earth was a blob of molten rock with just a thin solid film on its outer surface. Given your experience with materials of different densities, what can you infer about the relative densities of Earth’s atmosphere, ocean, rocky crust and mantle, and iron-rich core?

As explained below.

Explanation:

As the earth's history was formed by a collision that led to the formation of the moon that took place about some 4 billion years ago and the earth was a then a blob of molten rock with just a thin solid film on its outer surface.  What can be inferred about the different density of the earth is the earth atmospheric at that time was warm and solar radiation with a relative density and the oceanic crust has relatively more dense matter settled down and in the process known as the planetary differentiation.