Planet Earth Topic 4 Flashcards
(18 cards)
How deep is the Earth’s crust, and what is it?
5km deep, and this is where plants grow and humans walk on.
What is Earth’s mantle?
The layer below the crust that is made up of rocks.
What is the outer core made of?
Iron and nickel. It can get up to 5500 degrees!
What is the theory of continental drift?
Alfred Wegener thought that continents had all been connected once before because they found fossils from Africa, in North America.
What are the 2 main concepts given to plate tectonics?
- Earth’s crust was moving. The crust was not fixed in places as most people believed
- Earth’s crust is broken up into pieces called plates
What are the 3 types of plate movements that occur at plate boundaries?
- Diverging plates
- Converging plates
- Sliding plates
What is a convection current?
It’s the flow resulting from the rise of warmer materials and the sinking of cooler materials.
What are subduction zones?
When 2 plates collide or converge. One is shoved under the other.
What is a Seismograph?
Something used to measure earthquakes.
What is the Richter scale?
How to describe the magnitude or strength of an earthquake.
What are Seismic waves?
They are the energy waves that travel outward from the source of the earthquake.
What are Aftershocks?
They are smaller earthquakes and they can cause damage buildings to collapse.
What are Primary waves?
They travel the fastest of all 3 types of waves, and they can pass through solids liquids and gasses.
What are secondary waves?
They are the 2nd slowest of the 3 waves, and they can only pass through solids
What are surface waves?
They are the slowest, and do the most damage.
What is the focus of an earthquake?
The place deep in the crust where the earthquakes begin.
What is the epicenter?
The surface location directly above the focus.
What is a tsunami and how is it formed?
Some earthquakes happen under the sea. The water displaced by an earthquake can become huge waves called a tsunami!
