Our Changing planet Flashcards
What is the mantle?
The layer of the earth between its crust and its core. It is almost entirely solid
What is the core?
The centre of the earth. It has a liquid outer part and solid inner part
What is the atmosphere?
The relatively thin layer of gases that surround planet earth
Which layers of the earth are solid?
Inner core, mantle, crust
Where do the earths resources come from?
The crust, the oceans, and atmosphere
What causes techtonic plates to move?
Convection currents
What are techtonic plates?
The huge stabs of rock that make up the earths crust and top of its mantle
What are the convections currents in the mantle caused by?
Energy released by the decay of radioactive elements heating up the mantle
What causes earthquakes, volcanoes or mountains to form?
Where the plates meet huge force build up eventually the rocks give way changing shape or moving suddenly
Why can scientist not predict when and where earthquakes will happen?
We do not know up enough info or data or models to make accurate predictions
Why was wegener’s theory of continental drift not accepted for many years?
He could not explain why continents moved and at the time people accepted their own ideas
What is continental drift?
His idea was that the Earth’s continents were once joined together, but gradually moved apart over millions of years. It offered an explanation of the existence of similar fossils and rocks on continents that are far apart from each other.
What was wegener’s evidence?
the same types of fossilised animals and plants are found in South America and Africa
the shape of the east coast of South America fits the west coast of Africa, like pieces in a jigsaw puzzle
matching rock formations and mountain chains are found in South America and Africa
When do scientist think the earth was formed?
4.5 billion years ago
What was the earth like in the early stages?
Covered with volcanoes that released carbon dioxide, water vapour and nitrogen
