OUR CHANGING PLANET
Structure of the Earth
- The Earth is made of layers called the core, mantle and crust with the atmosphere around the outside.
- The Earth's limited resources come from its crust, the oceans and the atmosphere.
The restless Earth
- The Earth's crust and upper mantle is cracked into tectonic plates which are constantly moving.
- The tectonic plates move because of convection currents in the mantle that are caused by radioactive decay.
- Earthquakes and volcanoes happen where tectonic plates meet, butit is difficult to predict accurately when and where earthquakes will happen.
- Wegner's theory of continental drift was not accepted for many years.
The Earth's atmosphere in the past
- The Earth's early atmosphere was formed by volcanic activity.
- It probably consisted mainly…