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HISTORY IN THE ROCKS

 

 

 

Our planet earth is more than 2 000 million years old.

We have just celebrated the Second Millenium which is 2 000 years and we think that is a long time!!!

But it is nothing compared to the age of our planet.

 

 

Almost all of the earth's surface is made up of rock covered with a thin layer of soil. The oldest rocks are over 800 million years old and have been formed over the years from deposits of sand, clay, mud and the skeletons of tiny animals.

 


 

But all rocks are not the same!!!

There are rocks under the ground and on the ground.

There are rocks by the sea and under the sea.

 
   
 There are large rocks

 
   

There are small rocks and pebbles.

Pebbles are small pieces of rock that have broken off and have been worn smooth by the weather and the sea.

 
   


Some rocks DO NOT allow water to pass through them. These are called IMPERMEABLE rocks.

Some rocks ALLOW water to pass through them. These are called PERMEABLE rocks.

Some rocks are made up of lots of small rocks pressed together over the years. These are called CONGLOMERATE rocks.

In some rocks you will find the skeletons of tiny animals that lived and died many thousands of years ago. These are called FOSSILS.


Some rocks are taken from the ground for building and you can see them in houses, walls, gardens and parks.

 

Some rocks are extremely HARD and have been used through the ages as tools and weapons.

Granite and marble have been used for buildings and statues for thousands of years.

 

 

Flint is a very hard rock and was used by early man for arrowheads and for tools.

Some rocks are SOFT- can you think of a rock that is quite soft, white and is used for drawing?

Click here to find out.


 

How many different kinds of rocks can you think of? Tell us about them

Why not start a rock collection? Click here