The only planet in the solar system where life exists is Earth. It has water in liquid form, oxygen in the air, and the Sun's warmth to sustain life. Plants, animals, insects, birds, and humans live on the Earth . It is the most beautiful and unique planet because of the presence of life. It is currently the only planet with life. But it has not always been this way.

Earth was formed from a cloud of dust about 4.5 billion years ago. It was scorching hot initially. It resembled a massive fireball with molten rocks and hot gases. The hot gases cool down over time and form clouds. Constant rainfall kept its outer surface cold. The surface hardened as it cooled. Furthermore, the water collected on the surface as a liquid. The atmosphere was created by the gases. The conditions gradually improved, allowing life to emerge.

The Earth is made up of three layers— core, mantle, and crust. 

1. Core: The core is the Earth's innermost layer. It's the hottest part of the earth, and it's made up of dense minerals like iron and nickel. It has a solid inner core and a molten igneous outer core. The temperature of the inner core is around 4000°C which 7232°F.

2. Mantle: The mantle refers to the compact Earth's middle layer. It is the thickest layer, made up rocks rich in minerals such as iron and magnesium.

3. Crust: The outermost layer of the Earth is called the crust. It's the thinnest and coolest layer of all three layers. This is the layer where life exists. Oceans and mountains are also present on this layer. It is made of rocks such as granite and basalt. The crust is split into several plates. 

On top of the molten outer core, the crust and mantle float. Hot gases and molten rocks are constantly pushing them higher with considerable force. Mountains are formed as a result of this process. Some weak regions in the crust break open as a result of the extraordinarily high pressure that exists under the Earth's surface. These vents allow hot gases and molten rock, known as magma, to escape. This is how volcanoes are formed. When a volcano erupts, magma spews forth from the crater. The magma when reaches the surface of the Earth is called lava. 

• Volcanoes that erupt frequently are called active volcanoes. For example, Mount Etna in Sicily, Italy, has been erupting for 5,00,000 years.

• Volcanoes that haven't erupted in a long time but could erupt again are known as dormant volcanoes. A dormant volcano is Mount Kilimanjaro, which is located in Tanzania, Africa.

• Volcanoes that have not erupted throughout recorded history are known as extinct volcanoes. . For example, the Chimborazo volcano in Ecuador and the Shiprock volcano in New Mexico are both extinct volcanoes.

NGSS

4-ESS1-1

4-ESS2-1

4-ESS2-2

4-ESS2-2

ESS1.C:

ESS2.A:

ESS2.B

ESS2.E: 

ESS3.B:

ETS1.B:

Common Core State Standards Connections

• RI.4.1 - 

• RI.4.7 

• RI.4.9 - 

• W.4.7 

• W.4.8 

• W.4.9 

Mathematics

• 4.MD.A.1 

• 4.MD.A.2 

• 4.OA.A.1 

• MP.2 

• MP.4

• MP.5