The composition of rocks affects their densities and the densities of Earth's layers. Use what you have learned and the information in the table to answer the question.
| Rock/Mineral | Density ($gm / cm ^3$) |
| :------------ | :---------------------- |
| Eclogite | 3.45 |
| Perovskite | 4.03 |
| Rhyolite | 2.50 |
| Stishovite | 4.29 |
In which order would these rocks and minerals be found in the layers of Earth from the crust to the lower mantle?
A. eclogite, perovskite, rhyolite, stishovite
B. stishovite, rhyolite, perovskite, eclogite
C. stishovite, perovskite, eclogite, rhyolite
D. rhyolite, eclogite, perovskite, stishovite
Answer (2)
List the densities of the rocks/minerals.
Order the rocks/minerals from lowest to highest density: Rhyolite < Eclogite < Perovskite < Stishovite.
The order from lowest to highest density corresponds to the order from the crust to the lower mantle.
The order is: Rhyolite, Eclogite, Perovskite, Stishovite. r h yo l i t e , ec l o g i t e , p ero v s ki t e , s t i s h o v i t e
Explanation
Understanding the Problem We are given the densities of four rocks/minerals and need to order them as they would appear from the Earth's crust to the lower mantle. Since density increases with depth, we need to order them from lowest to highest density.
Listing the Densities The densities are:
Rhyolite: 2.50 g m / c m 3
Eclogite: 3.45 g m / c m 3
Perovskite: 4.03 g m / c m 3
Stishovite: 4.29 g m / c m 3
Ordering the Densities Ordering these from lowest to highest, we get: Rhyolite < Eclogite < Perovskite < Stishovite
Determining the Order Therefore, the order in which these rocks and minerals would be found from the crust to the lower mantle is: Rhyolite, Eclogite, Perovskite, Stishovite.
Examples
Understanding the density of different materials and their arrangement based on density is crucial in many real-world applications. For example, in construction, knowing the density of materials like concrete, steel, and wood helps engineers design stable and durable structures. Similarly, in geology, understanding the density of different rock types helps scientists model the Earth's interior and predict geological events. This concept is also used in the design of ships and submarines, where the density of materials determines buoyancy and stability.
The rocks and minerals should be ordered from the crust to the lower mantle based on their densities. The correct sequence is Rhyolite, Eclogite, Perovskite, and Stishovite. This corresponds to option D.
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