During the 1950s and 1960s, scientists used new technology like sonar and seismographs to study Earth,. They discovered that Wegener was right about continents moving but wrong when he hypothesized that moving continents plow through a stationary ocean floor. it turns out that the lithosphere is broken up into large tectonic plates containing both oceanic and continental crust. These plates are constantly moving. The continents don't plow through the ocean floor, as Wegener thought; rather, they are carried, along with the oceanic crust,m on larger plates.
Scientists believe that plates move because of convection currents in the mantle below the plates. In order to understand this, it is important to remember that the mantle, although solid, can flow slowly, like a thick fluid. Thick of a pot of thick pea soup on a stove. The stove warms the bottom of the pot, heating the soup from below. The heated soup rises to the surface, spreads out cools, and then sinks back to the bottom of the pot, where it is reheated and rises again. This type of cyclical flow is called convection.
Something similar is happening beneath the crust, in the mantle. Heat from deep in the Earth warms the mantle, and convection patterns in the mantles help move the plates above in the direction of the convection's flow.
Key Notes:
- 1950s - 60s scientists used sonar and seismographs to study Earth
- Discovered Wegener right about continents and wrong about continents plowing through ocean floor
- Lithosphere broken into large tectonic plates containing oceanic and continental crust which constantly move
- Plates move because of convection current in mantle
- Convection: is a cyclical flow - bottom warms up and rises, spreads out and cools, sinks back down, reheated and rises again - keeps going
- Heat from Earth's center warms mantles, convection patterns in mantle move the plates.
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