The Earth Flashcards
what are the four layers of the earth?
- The inner core which is made of iron and nickel
- The outer core is a hot solid layer
- The mantle has the properties of a solid but slowly flows due to radioactive decay
- The crust is very thin (5-50km) and it the outer most layer of the earth
what are tectonic plates?
Tectonic plates are plates that float on the mantle. These plates move due to the convection currents in the mantle but only a few centre metres a year in random directions
how can scientist predict natural disasters?
Strain in underground rocks, mini earthquakes and bulges in the earth
what was Alfred Wegener’s theory?
Alfred Wegener’s theory was that the earth was a jigsaw and that the earth had once been one country called Pangaea. He decided that very gradually the countries had split up and moved away from one another to form the world we now know today. The evidence he had for this was matching stones and fossils in different countries that once put together fitted perfectly
why was Wegener’s theory not accepted?
Wegener had incorrect calculations and wild predictions so he could not convince geologists that it was true and therefore could not get the support of the people
what were the three stages of the atmospheric change?
- Volcanoes gave out gases
- Green plants evolved and produced oxygen
- Ozone layer allows evolution of complex animals
What is the theory of primordial soup?
Miller and Urey believed that primordial soup was the mixture of gases in the atmosphere at the time; nitrogen, hydrogen, ammonia and methane. When lightning struck it caused them to become amino acids from which life gradually evolved. In 1950 Miller and Urey decided to replicate the experiment in miniature, they sealed the gases and left it for a week with a charge running through it. However only a few amino acids were made not enough found in humans
