Convection and Seafloor Spreading

Radiation

Energy transferred from the sun

Conduction

heat transfer between materials that are touching

Convection

heat transfer by the movement of a fluid

radiation, convection, and conduction

three types of heat transfer

heat

moves from a warmer to a cooler object

mantle and core

produces heat which causes convection currents in the earth

convection currents in motion

heating and cooling of a fluid caused by density changes combined with the force of gravity

hot fluid

particles move faster, less dense, rise

cool fluid

particles move slower, more dense, sink

density

the amount of mass in a given volume of a substance

mid ocean ridges

longest mountain ranges on Earth under the ocean

subduction

occurs at a deep ocean trench where the more dense plate sinks under less dense plate

seafloor spreading

plates move away, magma rises and adds more crust to the ocean floor

Seafloor spreading and Subduction

creates and destroys land/changes the size and shape of the oceans

Sonar

device that scientists use to map the ocean floor

parallel and symmetrical

pattern of magnetic stripes in rock on the ocean floor to support seafloor spreading

Seafloor Spreading

occurs at mid ocean ridges

Trenches

underwater canyon/ form where a more dense plate collides/sinks with less dense plate

Older and Colder Rock

forms farthest from the mid ocean ridges on opposite sides of the ridge

Younger and Hotter rock

forms at the mid ocean ridges where magma is rising and pushing away the rocks

Molten material

erupts inside the central valley of a mid ocean ridge

less dense magma

rises, density decreases, temperature increases

more dense magma

sinks, density increases, temnperature decreases

Seafloor Spreading

divergent boundary

Age of Rock

evidence to support seafloor spreading/youngest rock is closest to the mid ocean ridge/oldest rock is farthest from the ridge

Polarity of Rock

evidence of seafloor spreading/ Normal and Reversed Polarity of rock is parallel and symmetrical away form the ridge

Magnetic Reversals

the polarity or magnetism is recorded in the rock/has reversed multiple times/nort-south/south-north

Iceland

evidence of a divergent boundary/youngest rock in midle of island/oldest rock on edges of island