Rocks go through quite a process.
Geology is a common field of study for seventh graders. Rocks are a core element of the study of geology, so learning where they come from is important for seventh graders who are just being introduced to the topic. The rock cycle can be explained in simple, yet scientific, terms for seventh-grade students.
Beginnings
Rocks begin as liquid magma beneath the Earth's surface. As they cool, either on the Earth's surface or beneath it, they crystallize and become what is known as igneous rock.
On Earth's Surface
Once igneous rock reaches the Earth's surface, it is subject to the conditions that everything else on the surface experiences. Wind and water break down igneous rock into much smaller particles of sand or dirt. The term for this sand or dirt is sediment. Sediment gathers together in layers on the Earth's surface and over time is compacted together. This compacted sediment is called sedimentary rock.
Metamorphic Rock
The motion of the Earth's tectonic plates heats some sedimentary rock and hardens it. This hardening is called a metamorphosis. Rocks that have undergone this process are called metamorphic rocks. The tectonic movement pushes these rocks to the surface, and under extreme conditions creates mountains. Metamorphic rock from mountains is broken down by rivers or rain and becomes sediment, which starts the cycle over again.
Back to Igneous
Some metamorphic rocks are pushed back beneath the Earth's surface where they melt at extreme temperatures and become igneous rock, thus feeding the cycle. (see References 2).
Tags: igneous rock, Earth surface, beneath Earth, beneath Earth surface, Earth surface, metamorphic rocks