The Earth is a big ball, or sphere, made mostly of rock. Inside the earth the rock is melted, but the outside cover is hard rock. Less than one-third of the earth's surface is land and more than two-thirds are water. To go into a little more detail, the outside of the Earth is a crust of rock about 10 to 30 miles thick. The high parts of this crust are the continents and the low parts of it hold the waters of the oceans and the great inland seas and lakes. The crust of the Earth has two layers. The upper layer, which makes the continents, is made of granite. Under the layer of granite is a thick layer of very hard rock called basalt. Scientists believe that at the core of the Earth is a huge ball of molten iron, with a diameter of around 4,000 miles.
Fact file
The Earth is thought to be about 4,600 million years old. The oldest rocks so far discovered are up to 3,800 years old. We can calculate the age of the Earth by examining meteorites, and changes in atomic structure.
resources: Tell me why (Chancellor Press)
image 1: https://www.universetoday.com/wp-content/uploads/2008/05/Earths-layers.jpg
image 2: http://www.fountainoflifetm.com/wp-content/uploads/2015/02/earth.jpg
