Taking a closer look - the process
The above diagram shows the stages that rocks go through as the Earth forces them to change. It also shows how they never stop changing.
One thing that makes the rock cycle unique is the fact that there isn't a direct order for the rocks to change; instead, they can change in any way that they were forced to (Lofts and Evergreen, 2011).
There are rocks that have been unchanged on Earth for millions of years and may not change for millions more. Some rocks change very quickly, especially near the edges of the plates that make up the crust (Lofts and Evergreen, 2011).
Let's start with magma: as magma erupts from a volcano or below the earth, it begins to cool. This can be very quick, or quite time consuming. As it cools, the magma may trap minerals or gas. Either way, rocks that form this way are known as igneous rocks (Learner.org, 2014). There are many different kinds of igneous rocks; some are very unique, whilst others are closely related.
Through the earth's natural forces, igneous rocks get broken down; wind, rain, sunlight, and frost are common examples that will break down a rock. Little pieces of a larger rock get chipped off, and will travel to the ocean or rivers and sink to the bottom. In this state they are known as sediments (Learner.org, 2014).
Overtime, these sediments will collect more and more sediments on top of them. The water, however, is squeezed out whilst the sediments and compacted and cemented together into the shape of a sedimentary rock.
Due to the movements of the crust, rocks are constantly pulled below the earth's surface and vice versa. Once they're pulled under the surface, temperatures increase dramatically (about 25 degrees every kilometer [Lofts and Evergreen, 2011]). As the heat and pressure increases, the chemical properties of the rock are changed, and this change is known as metamorphism. Rocks that are formed this way are known as metamorphic rocks.
Put a chocolate bar in the hot sun and what happens? It melts! The same principle applies to rocks. Through movements of the earth's crust, rocks are pulled down farther and farther until the temperatures are hot enough to actually melt the rock. It takes between 600 and 1300 degrees Celsius to achieve this (Learner.org, 2014). After a rock has been melted it changes to a subatance known as magma. Then, once this cools, the whole process starts again.
The order that rocks take to change do not follow this distinct path; sometimes interruptions occur and they get altered in a different way. For example, an igneous rock does not necessarily change into a sedimentary rock; through heat and pressure, it can be re-made into a metamorphic rock. Similarly, a sedimentary rock can be changed back into sediments instead of a metamorphic rock. This rule can be applied to each rock.
One thing that makes the rock cycle unique is the fact that there isn't a direct order for the rocks to change; instead, they can change in any way that they were forced to (Lofts and Evergreen, 2011).
There are rocks that have been unchanged on Earth for millions of years and may not change for millions more. Some rocks change very quickly, especially near the edges of the plates that make up the crust (Lofts and Evergreen, 2011).
Let's start with magma: as magma erupts from a volcano or below the earth, it begins to cool. This can be very quick, or quite time consuming. As it cools, the magma may trap minerals or gas. Either way, rocks that form this way are known as igneous rocks (Learner.org, 2014). There are many different kinds of igneous rocks; some are very unique, whilst others are closely related.
Through the earth's natural forces, igneous rocks get broken down; wind, rain, sunlight, and frost are common examples that will break down a rock. Little pieces of a larger rock get chipped off, and will travel to the ocean or rivers and sink to the bottom. In this state they are known as sediments (Learner.org, 2014).
Overtime, these sediments will collect more and more sediments on top of them. The water, however, is squeezed out whilst the sediments and compacted and cemented together into the shape of a sedimentary rock.
Due to the movements of the crust, rocks are constantly pulled below the earth's surface and vice versa. Once they're pulled under the surface, temperatures increase dramatically (about 25 degrees every kilometer [Lofts and Evergreen, 2011]). As the heat and pressure increases, the chemical properties of the rock are changed, and this change is known as metamorphism. Rocks that are formed this way are known as metamorphic rocks.
Put a chocolate bar in the hot sun and what happens? It melts! The same principle applies to rocks. Through movements of the earth's crust, rocks are pulled down farther and farther until the temperatures are hot enough to actually melt the rock. It takes between 600 and 1300 degrees Celsius to achieve this (Learner.org, 2014). After a rock has been melted it changes to a subatance known as magma. Then, once this cools, the whole process starts again.
The order that rocks take to change do not follow this distinct path; sometimes interruptions occur and they get altered in a different way. For example, an igneous rock does not necessarily change into a sedimentary rock; through heat and pressure, it can be re-made into a metamorphic rock. Similarly, a sedimentary rock can be changed back into sediments instead of a metamorphic rock. This rule can be applied to each rock.