My Science School

What is the Earth made of?

The Earth is made up of elements. These are the simplest possible substances, which are composed of one kind of atom. Elements cannot normally be broken down into other substances, except under the special conditions that you might find inside the hot core of a star. A total of 92 different elements are found in nature. Other elements can be made in laboratories, but they have only a very short life.

Minerals, which make up the solid surface of the Earth, consist mostly of combinations of elements. The minerals gold, diamond and graphite are examples of single elements, while most others contain several elements. 

What are crystals?

Crystals are solid substances that are naturally formed into regular geometric, angular shapes. All crystals can be classified into seven systems. Sometimes a crystal is formed when water evaporates, and substances dissolved in the water gradually grow into a crystal. Other crystals are formed under great pressure. Diamond crystals are made when carbon dissolves in molten rock deep down below the Earth’s surface. The diamond crystallizes out and is later uncovered on the surface either by volcanic action or by erosion of the Earth’s crust. Other valuable gems are formed in a similar way, and most of them contain compounds of aluminium.

What is the Equator?

The Equator is an imaginary line drawn around the outside of the Earth. It lies midway between the North Pole and the South Pole, at the Earth’s broadest point.

The Equator was invented by map-makers because it makes a convenient point from which to measure distances, together with the geographic North Pole and South Pole. On a map, the Equator is positioned at 0 degrees of latitude. It divides the Earth into two halves, which we call the north and south hemispheres.