Science of the Earth.

By Edgar.

General Info.

Earth is the third farthest pant from the sun. It is the fifth largest and most densest of the eight planets in the solar system. Earth was formed 4.54 billion years ago. The Earth's atmosphere was formed through mass volcanic activity happening at that time and outgassing of both gas and water vapor. The oceans were formed through condensation of water and ice sent by asteroid, comets and proto planets.The Earth has a circumference distance of 40,075.017km. The Earth has a surface area of 510,072,000km2.

The Rock Cycle.

Description of Rock Cycle.

Above is a diagram based on the rock cycle process.

There are 3 Types of basic rocks of which are Igneous, Sedimentary, Metamorphic.

The Rock Cycle shows how each rock is formed and how it could undergo a transformation into a another type of rock.

There are 5 formation methods of which include:





Heat and Pressure.

Eg, Igneous Rock are formed through cooling of Magma of where it could undergo a transformation into sediments using the weathering method.

One single rock over a period of a million years may change from being a Igneous to a Sedimentary Rock using Weathering and compacting.

Link to 3 Basic Types of Rocks Mindmap.

Preview of Mindmap.

The 3 Basic Types of Rocks.

The 3 Basic Types of Rocks.

The 3 Basic Types of Rocks are:





How do they formed?

Igneous rocks are formed when a flow of magma cools down underground and becomes into a solid. Igneous have appearance of where it seems to appear that it has cool down. This method may be done deep inside the earth or just above the earth's surface.

Where can Igneous Rocks be found?

It can be found in places of where there is much volcanic activity in the area.

It can be found due to Magma that was erupted from a volcano or was forced to rise to the surface in the form of lava.

How is it there?

It is there as it is erupted out of a volcano and onto soil, of where it then cools down to where it forms into a igneous rock.

What do Igneous Rocks look like?

Igneous rocks have an appearance that is similar to that of a sponge as it contains many holes of which has been done due to the cooling process.

Where does it formed?

Igneous rocks form in three main places:

They formed in tectonic plates of where they fall apart, where the plates come together and places where continents are pushed together.

The Two Types of Igneous Rocks.

The two basic types of Igneous rocks are Basalt and Granite.


This type of igneous rock has the appearance of it being a dark fine-grained rock that could be seen when lava flows out or magma intrusions.


This type of igneous rock has the appearance of this type of rock has a light, coarse grained of appearance. It is usually formed deep in the grown and is later exposed due to erosion.


Granite is a common rock that contains at least 25% quartz and is usually used in construction due to its immense strength.

There are over 700 different types of igneous rocks.

Examples of igneous rocks include basalt, granite, pumice, obsidian, tuff, diorite, gabbro and andesite.

The word "igneous" comes from the Latin word for fire.

Different Appearances of Igneous Rocks.


How do they formed?

Metamorphic rocks are formed by pressure and heat. The pressure could be derived from the earth’s crust or plates on the earth’s crust pushing against each other. It could also be formed deep inside the earth’s crust caused by high temperatures and pressure.

Where can Metamorphic Rocks be found?

It could be found deep below the earth's crust or above the surface of the earth.

How is it there?

It is carried there as due to uplift of plates or erosion.

What do metamorphic rocks look like?

The appearance of common metamorphic rocks have a shiny kind of appearance and some also have crystals in them. They usually appear with dark or light bands. Metamorphic rocks can also be specified by its curvy surface.


Uplift and erosion help bring metamorphic rocks to the Earth's surface.

Examples of metamorphic rocks include anthracite, quartzite, marble, slate, granulite, gneiss and schist.

The word Metamorphic derives from the Greek words of change and form.

The oldest known rock lies in Canada. The Acasta gneiss, a metamorphic rock, is 3.96 billion years old.

Different Appearances of Metamorphic Rocks.


How do they formed?

Sedimentary Rocks are formed from compacting of sediments such as dead skeletons, dead plants, minerals,clay, sand, etc that are specified as sediments. The Rocks are then formed from these layers compacting against each other.

Other minerals that can form sedimentary rocks included are rocks that have been affected by weathering or erosion.

Where can Sedimentary Rocks be found?

It can be found on the bottom of places of where there used to be water such as lake and ocean beds.

How did it get there?

Sedimentary Particles or sediments can be carried through ice,wind, erosion and water.

What do Sedimentary Rocks look like?

Sedimentary Rocks are commonly seen with layers of minerals that have been compacted.

Types of Sedimentary Rocks.

There are 3 types of sedimentary rocks of which are organic, chemical and clastic.


The basic Sedimentary formed through compaction or cementing of layers of sediments.


Formed by when standing water evaporates of which causes the minerals in the water to be left behind such as salt and gypsum of which later form into layers turning into rocks.


Organic Sedimentary are rocks using the same method of compacting of layers but are composed of organic materials such as bones, dead plants, skeletons and shells.


Examples of Sedimenary rocks include rocks such as limestone, sandstone, mudstone, greywacke, chalk, coal, claystone and flint.

Sedimentary rocks cover over a majority of the Earth's rocky surface but only make up a small percentage of the Earth’s crust compared to metamorphic and igneous types of rocks.

The Different Appearances of Sedimentary Rocks.

The Earth's Layers.

Structure of the Earth's Layers.

The Earth is consisted of 4 different layers. Listed below are the names and the thickness.

Also whether the layers are composed of solids or liquids and their exact temperatures.

Crust - 0 - 100 km Thick ( Solid ) - Normal Earth Temperature.

Mantle - 2900 km Thick ( Solid ) - 1000º - 2500º

Outer Core - 2200 km Thick ( Liquid ) - 4000º

Inner Core - 1200 km Thick ( Solid ) - 5000º

FAQ of the Earth's Layers.

The Earth’s Layers FAQ

1. What are the Earth’s layers composed of?

There are composed by the following layers: Crust, Mantle, Outer Core and the Inner Core.

2. What is the mantle composed of and how much volume does it take up of the earth’s volume?

The mantle is composed mostly by these following elements in percentage: 44.8% Oxygen, 21.5% Silicon and 22.8% Magenesium. The other 11% are formed by heavy elements that can be found on the periodic table. The mantle takes about 84% of the earth’s volume.

3. What is the distance between the crust and the inner core?

The distance from the crust to the inner core is 6300 km.

4. What is the inner core composed of and is it a solid or liquid?

The inner core is entirely made of iron and is a solid. It is a solid as it is under immense pressure from the outer layers.

5. What is the temperature inside the mantle?

The temperature inside the mantle ranges from 1000cº - 2500cº.

6. How much layers are in the mantle layer?

There are four layers in the mantle, they consist of the lithosphere, asthenosphere, the upper mantle and the lower mantle.

7. What causes the earth formations and earthquakes?

Earthquakes are caused by motions in the asthenosphere layer in the mantle causing mountain formations, volcanoes and earthquakes.

8. What is the thickness of the inner core and outer core?

The inner core is 1200km thick and the outer core is 2200km thick.

9. What types of crust are there?

There are 2 types of crusts of which are the oceanic and continental.

10. What percentage of mass of the inner and outer core does it make up of the earth’s mass?

The inner and outer core both make up 32.5% of the earth’s mass.

11. What is the circumference of planet Earth?

The Earth has a circumference distance of 40,075 km in the equator.

12. Is it true that if you stand in the middle of the equator, you move faster?

You may feel that you are standing quite still but you still actually moving. Depending on where you are on the Earth, you could be spinning through space at a speed of 1,000 miles per hour. People in the equator would move faster compared to people who lived on the Northern and Southern poles.

13. How old is plant Earth?

According to researchers that calculated the age by dating the age of both rocks and meteorites. The calculation turn up the number of an age of 4.54 billion years ago.

14. Where was the world’s largest earthquake and what magnitude.

The world’s largest earthquake happened in Chile on May 22, 1960 and had a magnitude of 9.5 on the Richter scale.

15. What’s the hottest place on the earth’s crust, where is it located and what was the temperature?

The hottest place on Earth is in El Aziazia, Libya of where temperature’s could reach 57.8 degrees Celsius.

16. Where is the coldest place on Earth and what was its temperature?

The coldest place is located in Antarctica in Russia’s Vostok station of where the temperature could reach minus 128.6 degrees Celsius.

17. What is tallest point of the earth’s crust?

The Tallest point of the earth’s crust is Mount Everest in the Himalayas reaching a height of 8,848 metres.

18. What percentage of the earth’s crust is covered by ocean?

About 70% of the earth’s crust is ocean, yet sadly human have only discovered only 5 percent of it. Meaning 95% of the earth’s crust hasn’t been seen by humans.

19. Is there gold underneath the ocean?

Yes there are actually 20 millions tons of gold just underneath the ocean.

20. What was the largest volcanic eruption ever recorded by humans?

Humans have recorded a large eruption that occurred on April 1815, at the peak of the explosion of Mount Tambora on the island of Sumbawa, Indonesia. It is ranked at 7 in the VEI ( Volcanic Explosivity Index ) which meant that it was super – colossal . The explosion was so loud that it could be heard on the island of Sumatra, which was located 1,930km away.

21. What is the largest ocean basin?

The world’s largest ocean basin is located in the pacific ocean covering an area of 155 million square kilometres. The basin is so large that it could fit most of the world’s continents.

22. What is the driest place on the earth’s crust?

The driest place on the earth’s crust is in the Atacama desert of Peru and Chile. There are places in the area of where rain has never been recorded.

Videos about the Earth's Layer's

Layers of the Earth


Why do volcanoes erupt and what's the difference between Lava and Magma?

In a eruption, lava is discharged out from beneath the Earth's crust up to the Earth's surface. This lava is actually hot melted rock called magma. Underneath the Earth's crust is a layer called the mantle, which is made up of different sizes of plates that are always moving and shifting. Sometimes the plates separate which causes heat to the the mantle of where it melts into magma. The magma comes up through the crack between the plates. It spreads out, cools down, and becomes rock again. The solid magma stays underneath the Earth's surface. Rocks that have become solid or have been cooled from magma are called igneous rocks.

When plates collide one plate can slide over the other. This also causes the mantle underneath it to melt. The magma pushes upwards, melting more rock. The hot magma collects underneath the surface of the Earth. If it is high in pressure or a crack opens in the crust, the magma discharges out. Now it is called lava.

The difference between Lava and Magma are:

Magma is found underneath the earth's surface while Lava is found above the Earth's surface.

Reference -

Video on Why volcanoes erupt?

Why Volcanoes Erupt When They Do

Video on How do volcanoes erupt?

Volcano Eruptions : How Do Volcanoes Erupt?

Video on What makes a volcano erupt?

What Makes a Volcano Erupt?


What causes Earthquakes?

The tectonic movements of the Earth's plates causes earthquakes. Earthquakes usually happen if one tectonic plates slide below or over another tectonic plate.

Reference -


How do mountains formed?

Mountains are formed when tectonic plates collide with each other causing both sides of the plates to rise forming mountains ranges. Mountains ranges can also be formed on faults lines of where parts of tectonic plates are rised and tilted causing mountains to be formed.

Mountains could also be formed through erosion of water.

Also Magma could also form mountains when Magma is forced to rise or be pushed up beneath the earth's surface. It usually doesn't crack but forms when the magma has cooled down.

Reference -