All about Rocks

• Science
• 5th Grade

Welcome class 

TODAY WE ARE LEARNING ALL ABOUT ROCKS 

AND HOW THEY ARE FORMED

What's a rock 

Im sure we all know what a rock is but do we know the actual scientific definition  rocks are the solid mineral material forming part of the surface of the earth and other similar planets, exposed on the surface or underlying the soil or oceans.

THERE ARE 3 MAIN TYPES OF ROCKS 

1. IGNEOUS ROCKS

2.SEDIMENTARY ROCKS

3.METAMORPHIC ROCKS

What are igneous rocks ?

Igneous rocks are rocks formed when hot magma crystalizes and solidifies they do not include any fossil deposits this is because  deep inside the earths crust erupts due to  the heat from these rocks they do however sometimes contain more that one mineral deposit  like Feldspars, or quartz 

There are two main types of igneous rocks Extrusive, Intrusive/ Plutonic 

Intrusive rocks 

Intrusive rocks are formed  from magma that has cooled and solidified inside the crust of the earth 

Intrusive rocks appear like crystals because of the slow cooling process , they also appear bigger, coarser and more grained than extrusive

    

There are many types of igneous intrusive rocks including  diabase ,diorite,  gabbro, granite, pegmatite

Extrusive Rock

Extrusive rock is formed when magma emerges from underground and cools on or near the Earths surface 

These rocks appear smaller and shinier than intrusive rocks because it cools faster 

Unlike intrusive rock they are fine grained and appear glassy and have small bubbles called vesicles from trapped lava 

Examples of extrusive rocks are Basalt, Pumice, Scoria, and vesicular basalt

 

Sedimentary 

Sedimentary rocks consist of fragments or pieces of rocks called sediments carried in rivers and deposited into lakes and oceans. When these sediments are buried they loose water and cement to form the rock some examples of  sedimentary rocks sandstone, limestone, and shale

sedimentary rocks can even form from the remains of plants or animals.The little pieces of materials  collect in low-lying areas like and around lakes, oceans, and deserts. They are then compressed by the weight of things on top and around them to turn them back to rocks 

Metamorphic rocks

 Metamorphic rocks come from igneous or sedimentary rocks sometimes these sedimentary rocks and igneous rocks get trapped under the earth where there is a high temperature and  a lot of pressure due to this extreme pressure and temperature the rocks go through chemical changes called metamorphosis they then change to metamorphic rocks some examples of metamorphic rocks are  quartzite and marble

So now that we know all about the different type of rocks and how they formed we are going to do a quick fun activity I want everyone to take a few moments to create their own rock draw a picture of your rock friend and tell me what type of the three rocks we learned about it is and don't forget to name it 

WHAT IS ANOTHER NAME FOR AN IGNEOUS ROCK