Aaron's+Report

The whole earth is made of rocks and minerals. in the earth there is a liquid core, mantle, and a hard crust on the outside. The Liquid core is in the center of the earth. It is made of iron and nickel and is very very hot. It makes up around 30% of the earths mass. The mantle is the biggest section of the earth at 1800 miles thick plus is very hot. It has two parts the Asthenosphere and the Lithosphere. it is a solid casing of the earth that makes up about 70% of the earths mass. The crust is the outer most part of the earth it is only a few miles thick and that is very thin for part of the earth. It makes up less than 1 percent of the earth’s mass.

Rock is a hard substance that is part of the earth. Rocks can be used in many ways. They can be used for roads, buildings, counter tops, jewelry and many other things. Rocks are divided into three categories, igneous, sedimentary, and metaphoric. They are classified by how they are formed.

Most rocks are made up of many minerals and/or magma. A rock is always made up of two or more minerals except for rocks that are only made up of magma. There are many other ingredients to rock.

When rocks break down into smaller and smaller pieces, they turn into sand. If you look at sand under a microscope you will see that the sand is made up of the same minerals of the rock it came from.

Ignaceous rock is formed from magma with temperatures from 1400 to 2300 degrees then it cools, and a rock is formed. They make up over 95% of the earth’s crust and upper mantle.

Sedimentary rock is formed from loose materials called sediments. They can contain plant and animal remains. Sedimentary rocks cover 75% of the earth’s surface. Many of these rocks contain limestone, sandstone, and shale. Most of the visible rocks on the earth’s surface are of this type. There are three types of sedimentary rocks. Clastic: your basic sedimentary rock. Organic: any collection of sedimentary debris caused by organic processes. Chemical: many of these form when standing water evaporates leaving dissolved minerals behind, made up of shell, bones, and teeth of animals. Just about every rock becomes sediment.

Metaphoric rocks get their names from Meta – change and morph – form. It is made up of minerals forming together. Almost any rock can be a metaphoric rock. Metaphoric rocks have morphed into another kind of rock. These were once sedimentary or igneous rocks. When rocks are under tons and tons of pressure it causes heat to build up. This causes them to change. If you examine metaphoric samples closely, you will see how flattened some of the grains in the rock are.

For thousands even millions of years little pieces of earth have been broken down and eroded by wind and water. These little bits of earth are washed downstream where they settle to the bottom of rivers, lakes, and oceans. Layer after layer of eroded earth are deposited on top of each other. These layers are pressed down until the bottom layer slowly turns into rock.

Much of the earth’s crust is covered by water, soil, sand, and ice. Soil is very important to all life on earth. It supports plant life which we cannot live without. Soil is made up of sand and decomposing plants and animals. Different soil has different names such as clay, silt, mud, dirt, dust, and potting soil. If you dig deep enough you will always hit rocks.

Rocks like mountains do not last forever. The oldest rock is dated from 3.8 to 4.28 billion years old. The oldest substantial chunk of Earth's crust has been found in Greenland, and dates back at least 3.9billion years. The weather, running water, and ice wear them down.

I hope that you have learned all about rocks. If you learn even more about rocks you might write a book on rocks someday. Now remember everything you learned about rocks because it may come in handy any day.