The Earth has three main layers:
Starting from the outermost layer, the Earth is composed of the crust, followed by the mantle, and finally the core.
The Earth’s crust is the thinnest of the three layers, and it is the solid surface where we stand and live. This rocky layer is divided into large pieces called tectonic plates. The movement of these tectonic plates is responsible for many geological activities, such as earthquakes, volcanic eruptions, and the formation of mountain ranges.
However, the thickness of the crust varies depending on the location. In some areas, it is very thick, while in other areas it is very thin. We live on the thicker areas of crust, known as continental crust, which are higher ground. Oceans lie above a thinner type of crust, known as oceanic crust, which is generally submerged in water and not as thick as continental crust. The thinner areas of the crust can cause problems like earthquakes.
The two types of crust are very different from each other and are made up of different minerals and rocks. Continental crust is usually thicker and less dense than oceanic crust. On average, continental crust is around 35 to 40 km thick, while oceanic crust is typically around 5 to 10 km thick.
Also, continental crust is generally older than oceanic crust. Some areas of continental crust are more than 4 billion years old, while most oceanic crust is 200 million years old or younger.
The Earth’s mantle is the thickest of the three layers. It is made mostly of solid rock and behaves like a solid; however, it can also flow beneath the crust. Due to convection currents, hot rock slowly rises while cooler rock falls.
The centre of the Earth is called the core, which is divided into the inner core and the outer core.
Both iron and nickel are magnetic, contributing to the Earth’s magnetic field.
In the periodic table below, iron (Fe) is circled.
While iron is a common element on Earth, we have also discovered elements that are heavier than iron. This suggests that Earth was formed from the explosion of a supernova.
A supernova is an exploding massive star that disperses heavy elements like iron, as well as elements heavier than iron, into space. This eventually formed our planet. Elements heavier than iron only form during supernova explosions.